Resolved Clutch Drag Gremlin

[Tony J]

Just replaced master and slave with OEM parts. Car has a ss braided line to slave.

Also the pedal assembly has 0 slop as it's been welded and comes alllll the way up to the stopper and engages the master as soon as you touch it.

I noticed my pivot ball may need shimming as the clutch fork is off center.

I have seen so many posts similar to this with different results. I get it, I am going to pull the trans.

That being said I've seen guys shim their pivot balls too much, I've seen clutch springs bust. I've personally done it (broke clutch) but that was a money shift and had it lock me out of gear afterwards.

Im getting no symptoms other than my pedal bottoms out on the floor before the fork can fully disengage.

I bleed bleed bleed it gets better but at idle will make a subtle grind into first and won't grind a single gear at idle afterwards. The car drives decent I know I shouldn't drive it but second synchro is gone and I've got a spare trans on the floor waiting to go In.

I do jacks drag test. Car is in garage on shop floor, first gear take it to red line and it lunges at 6500 rpm

I bleed bleed, extend master rod fully out and still nothing.

I noticed i may be hitting the inner bellhousing.. again aware i may need to pull tranny but skeptical on the pivot ball shimming as I've seen people say it can be over extended.

Im confident the hydraulics are working. My slave pushes so far the inner cylinder almost wants to pop out i swear.

I would appreciate any input, any ideas that you guys may have. Experiences.

Please leave the skeptism behind. 6 local dsm guys swore it was my assembly so I pulled it. Then it was the master or slave I replaced both last week.

Clutch and pp are a used set from my last talon with less than 5000 km on it surely. It looked brand new when I put it in.

Now it's a pivot ball? What next? What are your experiences?

Tony.

 

[TuskeeTuner]

How's your flywheel? I know it's out of "Left Field" but you didn't mention it. I've never shimmed my pivot ball.

 

[bastarddsm]

Compare how far the tob must travel on a stock clutch/flywheel to your current setup. That may answer a few questions.

 

[pauleyman]

Try this read.

Clutch basic 101: A clutch basics thread for everybody

The following statements are my opinions but they are based on 26 years of wrenching on mitsubishis and 21 of those years on DSMs. This applies to 4g63 cars only. I am not commenting on a 420a clutch although some things do apply.This is not meant to be just DSM specific but could be applied...

www.dsmtuners.com

 

[CrackedDSM]

OEM Master and OEM slave? This is important.

 

[Anfurnyy]

How is your clutch master rod adjusted? Have you actually done proper adjustment? And not just throwing something at the wall and try it.

1) you could have your master cylinder bleed port blocked off, so fluid can't ever return to the reservoir. This is equivalent to riding the clutch all the time, clutch is no longer "self adjusting"

2) you could have your master rod adjusted too far IN which would cause a bunch of travel and no fluid to be pushed to the slave, which means the clutch won't disengage completely.

-Adjust pedal all the way up for maximum pedal travel, start extending the rod until it gets tight, not hard, Tight.

- go into the engine bay and compress the slave by hand. If you are able to, keep extending the rod.

- you'll get one of these first; run out of master rod, or you'll be unable to push the slave in by hand.

- if you run out of rod, move upper pedal stop in ( closer to firewall) and continue on.

- if you can't compress the slave, you've blocked the bleed port and you need to back the rod off very slightly until you can compress the slave by hand.

Once you've got it where pedal has most travel and you can compress the slave then lock it down and test your slave again.

This method ensures that as soon as any travel happens on the clutch, the fluid that the master is pushing is sent to the slave and not pushed back into the master cylinder reservoir. If you don't make sure that the bleed port is blocked almost immediately you'll just be pushing fluid into the res until the port is blocked and THEN it'll send fluid into the slave.

This is a gif of a brake master but it's the same exact concept .

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[luv2rallye]

When bleeding did you do post 21's "Step Two: Next have ..." here: https://www.dsmtuners.com/threads/clutch-will-not-disengage.460266/post-153268772

 

[Tony J]

How's your flywheel? I know it's out of "Left Field" but you didn't mention it. I've never shimmed my pivot ball.

This is why guys shim pivot tho. So that's why it leads me to believe it's just a step height issue because in bottomiing out on the inner bell I feel like for sure. I haven't had a helper but when I push the pedal to the floor and wedge it with a jack handle, then climb under car Im almost certain it's hitting. You cant hear the "tink" from inside the car when I pump it up

The fly is just a stock cast fly. Didn't look resurfaced.

How is your clutch master rod adjusted? Have you actually done proper adjustment? And not just throwing something at the wall and try it.

1) you could have your master cylinder bleed port blocked off, so fluid can't ever return to the reservoir. This is equivalent to riding the clutch all the time, clutch is no longer "self adjusting"

2) you could have your master rod adjusted too far IN which would cause a bunch of travel and no fluid to be pushed to the slave, which means the clutch won't disengage completely.

-Adjust pedal all the way up for maximum pedal travel, start extending the rod until it gets tight, not hard, Tight.

- go into the engine bay and compress the slave by hand. If you are able to, keep extending the rod.

- you'll get one of these first; run out of master rod, or you'll be unable to push the slave in by hand.

- if you run out of rod, move upper pedal stop in ( closer to firewall) and continue on.

- if you can't compress the slave, you've blocked the bleed port and you need to back the rod off very slightly until you can compress the slave by hand.

Once you've got it where pedal has most travel and you can compress the slave then lock it down and test your slave again.

This method ensures that as soon as any travel happens on the clutch, the fluid that the master is pushing is sent to the slave and not pushed back into the master cylinder reservoir. If you don't make sure that the bleed port is blocked almost immediately you'll just be pushing fluid into the res until the port is blocked and THEN it'll send fluid into the slave.

This is a gif of a brake master but it's the same exact concept .

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I run out of master rod based off your method!

OEM Master and OEM slave? This is important.

Yes oem stuff. I've seen my cheap slaves suck air back in, but my car only burps into gear in 1st sometimes and second always. But I'm an engine braking asshole...2nd gets it the worst.

All other gears don't grind when driving. So I feel like it's just the smallest bit of throw im mossing but it's not a hydraulic issue as I'm very close to the inner bell if not touching already fully extended and my slave is like borderline popping out of its cylinder.

 

[Anfurnyy]

I run out of master rod based off your method!

I think most people do. Extend the upper stop and bring the pedal closer to the firewall and repeat

 

[Tony J]

Youre saying screw the rod into the pedal assembly more? Right now it's flush with the backside of the c clip, it's tough to spin... should I keep going till it's slacked off?

My whole thing is why by lowering the pedal will I gain anything? Not trying to be combative it just seems counterproductive to shorten the pedal swing. Right now my pedal is hitting metal .. I've got the carpet and insulation cut at the top for max travel .

I think most people do. Extend the upper stop and bring the pedal closer to the firewall and repeat

 

[Anfurnyy]

Youre saying screw the rod into the pedal assembly more? Right now it's flush with the backside of the c clip, it's tough to spin... should I keep going till it's slacked off?

My whole thing is why by lowering the pedal will I gain anything? Not trying to be combative it just seems counterproductive to shorten the pedal swing. Right now my pedal is hitting metal .. I've got the carpet and insulation cut at the top for max travel .

Really what you're trying to do is keep the most amount of travel in the pedal assembly while still just barely not blocking off the bleed port inside of the master cylinder. If you're running out of rod and you can still push the slave in by hand then you need to move the pedal forward, which in turn pushes the master rod into the cylinder more. Then just continue to do that until you're right before blocking the port with the pedal resting. What blocking the bleed port right as you push your pedal in does is forces the fluid in the master cylinder into the clutch line and into the slave, making it disengage your clutch. If you have your rod way too far before the port you get a whole bunch of pedal travel that does absolutely nothing but push fluid into the master reservoir. Look real close at that gif I posted above. It should make sense.

Normally shorting the pedal IS counterproductive but you really need to find a zero point to start with everything from.

Youre saying screw the rod into the pedal assembly more? Right now it's flush with the backside of the c clip, it's tough to spin... should I keep going till it's slacked off?

My whole thing is why by lowering the pedal will I gain anything? Not trying to be combative it just seems counterproductive to shorten the pedal swing. Right now my pedal is hitting metal .. I've got the carpet and insulation cut at the top for max travel .

Clutch

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[Tony J]

Really what you're trying to do is keep the most amount of travel in the pedal assembly while still just barely not blocking off the bleed port inside of the master cylinder. If you're running out of rod and you can still push the slave in by hand then you need to move the pedal forward, which in turn pushes the master rod into the cylinder more. Then just continue to do that until you're right before blocking the port with the pedal resting. What blocking the bleed port right as you push your pedal in does is forces the fluid in the master cylinder into the clutch line and into the slave, making it disengage your clutch. If you have your rod way too far before the port you get a whole bunch of pedal travel that does absolutely nothing but push fluid into the master reservoir. Look real close at that gif I posted above. It should make sense.

Normally shorting the pedal IS counterproductive but you really need to find a zero point to start with everything from.

Clutch

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I took the car for a drive tonight cause I'm that guy, put 20 km on it. No issues with the clutch but when I got back to the shop I heard a ticking sound when I put the clutch in... I have no idea what's going on in there but I pulled the wheels off popped the axles out and will pull trans tomorrow to inspect... the car sat all year last year at some piss poor shop waiting for a head gasket install it's not sitting this year .

 

[bastarddsm]

Put one of these on and see what happens. https://www.rockauto.com/en/moreinfo.php?pk=1404113&cc=1434250&pt=2044&jsn=482 You'll need to rig it some. Probably have to bleed it before you bolt it on the trans, and I think you gotta use through bolts and stack up some washers to get things to line up.

You still need to check the clutch vs a stock clutch and see. The stock shit is marginal with a stock clutch. Anything aftermarket and good luck, that's why there are so many fixes that work for some and not others. It's a very fine line.

Oh and if you have a full braided line from the master to the slave throw that in the f***in trash, and use the shortest flex line possible.

 

[Tony J]

Really what you're trying to do is keep the most amount of travel in the pedal assembly while still just barely not blocking off the bleed port inside of the master cylinder. If you're running out of rod and you can still push the slave in by hand then you need to move the pedal forward, which in turn pushes the master rod into the cylinder more. Then just continue to do that until you're right before blocking the port with the pedal resting. What blocking the bleed port right as you push your pedal in does is forces the fluid in the master cylinder into the clutch line and into the slave, making it disengage your clutch. If you have your rod way too far before the port you get a whole bunch of pedal travel that does absolutely nothing but push fluid into the master reservoir. Look real close at that gif I posted above. It should make sense.

Normally shorting the pedal IS counterproductive but you really need to find a zero point to start with everything from.

Clutch

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I ended up pulling the front end apart just need to pop axles and drop ex and tease unfortunately trans at this point.

I got a ticking sound tonight after a short drive. Put 20km on the car went back to shop, parked it. Clutch in and "tick,tick tick, tick tick, so I'm interested to see what's going on in there.

Planned on putting a couple washers behind the pivot ball, assuming this would save some adjusting? By whitening the distance the fork needs to travel to contact the pp it should in theory help a bad step height.

That being said I've cant see how a stock flywheel would be stepped incorrectly. The clutch i installed was a stock part from RTM racing, exedy brand I believe. I've used their clutches in all my dsms never had an issue until this specific car.

I'm hoping there's something obvious inside. Like a bent pp finger, broken spring, loose flywheel bolts.

I truly believe the fork is hitting the inner bell hence my reasoning for jumping in and pulling the trans.

Couple pics included. Showing how close my fork is.. pics taken from a video.

Other pic is showing slave fully extended you can see the piston almost out of the bore which leads me to believe it needs a shim to center my fork as it's center at best

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Put one of these on and see what happens. https://www.rockauto.com/en/moreinfo.php?pk=1404113&cc=1434250&pt=2044&jsn=482 You'll need to rig it some. Probably have to bleed it before you bolt it on the trans, and I think you gotta use through bolts and stack up some washers to get things to line up.

You still need to check the clutch vs a stock clutch and see. The stock shit is marginal with a stock clutch. Anything aftermarket and good luck, that's why there are so many fixes that work for some and not others. It's a very fine line.

That slave is the right bore? Throw? W.e you call it ive thought about getting other slaves but worry about the bolt pattern .

 

[Tony J]

Pulled the trans today, took the pivot ball and shims from another trans in had and transfered it. My fork sits where it should now. Pedal feels good, still feels like it's disengaging on the floor but it feels like a full disengagement. So I'm hopeful. I re bled. Pedal is stiffer than ever.

Car is still in air as I spent all day pulling trans and putting the c u next Tuesday back. Best way I found was not the jack. You gotta bench press that sucker in, a lil finesse... I usually pull the engine and trans but I figured I'd try something different..

Tomorrow I will pop the axles back in, t case and exhaust and do a drag test. Clutch in rev to 7000..

It's been consistently moving at 6500 so I'm praying these 2 shims and the other ball do the trick. The clutch and pp looked fine I did take them off to inspect cause it would be silly not to. All looked typical. Hot spots but nothing I haven't seen before.


Here's hoping. If this doesn't work I have no idea what to do next. Slave master are both oem and bled thoroughly. Like every method you can find on here. Pedal assembly is welded and the pivot ball is now shimmed

Will update tomorrow.

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[jed344]

I did not see if you confirmed the flywheel step height? There has been some configurations over the years we needed to shim the pivot ball but generally when everything was new and correct step height the fork would be in correct location. We then would just adjust to max travel and life was good. These cars all had new OEM master and slave, SS braided line from master to slave. Stock or ACT flywheel with step height confirmed.

 

[bastarddsm]

Unless the step height is off like 0.05" or more it is not the problem. The fingers are close enough to say it's not the step height 100%. Your slave is leaking - it's junk. And if you struggled to get the trans on the car the clutch disc is now bent and junk. Use a cherry picker from the top.

If the clutch doesn't disengage within the first half of the travel you are going to have problems.

 

[Tony J]

Unless the step height is off like 0.05" or more it is not the problem. The fingers are close enough to say it's not the step height 100%. Your slave is leaking - it's junk. And if you struggled to get the trans on the car the clutch disc is now bent and junk. Use a cherry picker from the top.

If the clutch doesn't disengage within the first half of the travel you are going to have problems.

There was two of us there. It was well supported. If it got hung up it was nooooo where near the input shaft and clutch. It was a bugger to get clocked the right way but at no time was it suspended my the clutch.. NOW the speedo cable.. that was a different story.. im in the market for one of those . I have another slave here aswell I could try..i don't believe that slave is bad as the pedal is rock solid. Hard to say, I'll wipe it off and pump it a bunch. The whole reason I shimmed was because the fork was so close to the inner bell housing. I don't believe step height is off as this fly and clutch are out of a previous talon I had that had zero drag. The only thing that's changed is the pedal assembly and the hydraulics and the trans. It was a straight motor swap as I had a 94 with 150,000 km and the 91 I have now has 259,000 km on it, so I kept my motor and fly, I have 2 exedy clutches and stock pps, on the shelf. I didn't change a thing except the pivot with 2 shims the fork from the 2g trans and the throw out bearing from the 2g trans

Pictured to the left is the tb that was in my car. I believe it was making a ticking noise when I put the clutch in. I noticed it was missing a ring around the outside. To the right is the fork and throw out from the 2g trans I have, I also have a fork and a throw out from a fwd talon and it's the same as the 2g so the tob is suspect to me...

I will do a drag test tomorrow once it's buttoned up and go from there. I understand I may have to play with the master rod and bleed? And if I have issues I'll try the slave off the 2g aswell.

That slave pictured has less then 500 miles on it. My car sat for 10 months, and the master is new as of this week. Pedal assembly welded as mentioned. 0 slop.

Well see what happens.

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[CrackedDSM]

There was two of us there. It was well supported. If it got hung up it was nooooo where near the input shaft and clutch. It was a bugger to get clocked the right way but at no time was it suspended my the clutch.. NOW the speedo cable.. that was a different story.. im in the market for one of those . I have another slave here aswell I could try..i don't believe that slave is bad as the pedal is rock solid. Hard to say, I'll wipe it off and pump it a bunch. The whole reason I shimmed was because the fork was so close to the inner bell housing. I don't believe step height is off as this fly and clutch are out of a previous talon I had that had zero drag. The only thing that's changed is the pedal assembly and the hydraulics and the trans. It was a straight motor swap as I had a 94 with 150,000 km and the 91 I have now has 259,000 km on it, so I kept my motor and fly, I have 2 exedy clutches and stock pps, on the shelf. I didn't change a thing except the pivot with 2 shims the fork from the 2g trans and the throw out bearing from the 2g trans

Pictured to the left is the tb that was in my car. I believe it was making a ticking noise when I put the clutch in. I noticed it was missing a ring around the outside. To the right is the fork and throw out from the 2g trans I have, I also have a fork and a throw out from a fwd talon and it's the same as the 2g so the tob is suspect to me...

I will do a drag test tomorrow once it's buttoned up and go from there. I understand I may have to play with the master rod and bleed? And if I have issues I'll try the slave off the 2g aswell.

That slave pictured has less then 500 miles on it. My car sat for 10 months, and the master is new as of this week. Pedal assembly welded as mentioned. 0 slop.

Well see what happens.

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He said the same thing to me when I dropped and reinstalled my transmission(like four times too)by myself, and he was wrong. Disregard that particular bit of advice.


I'm very curious what your problem ends up being.

 

[Tony J]

He said the same thing to me when I dropped and reinstalled my transmission(like four times too)by myself, and he was wrong. Disregard that particular bit of advice.


I'm very curious what your problem ends up being.

I appreciate that fact that you didn't just blurt out step height... it's only dragging at 6500 not all the time and the car goes in gears when clutch is in. So I don't believe it to be a major problem..

I won't be able to get to the car till later tonight to button it up but those shims translated to roughly an inch of fork movement towards the engine, so that being said, I'm optimistic.

Like I said in my previous post any doubts I'll swap the new slave in.. Im on daddy duty tonight

So after 9pm est I'm hitting the shop

His concern makes sense but my trans was far far away from the input shaft and when it did go in it was one swift alley oop.

 

[bastarddsm]

He said the same thing to me when I dropped and reinstalled my transmission(like four times too)by myself, and he was wrong. Disregard that particular bit of advice.


I'm very curious what your problem ends up being.

Go get a datalog of taking that thing to the 7500-8000 and pulling a 1-2 shift as fast as you can whilst still WOT. Till you can get one like sub 400ms it still drags. Rolling forward on the 2-step is just the tip of the iceberg as far as clutch drag goes. I guess pulling the trans x times to not fix the problem is good exercise.

 

[Ludachris]

@twicks69 - any feedback you could offer?

 

[twicks69]

@twicks69 - any feedback you could offer?

Well, I see a lot of used parts for clutch forks and TOB's, how about doing some measurements of the clutch forks, measuring the thickness of the fork fingers that the TOB rests on, measuring the pivot ball pocket depth and visual wear, visually inspecting the retainer clip that it is flat and tight on the pivot ball. Grab a pivot ball and put it in a vise, mount a clutch fork to it, and see if it has any in/out movement at the pivot ball that will cause slop and pulling out of the fork from the pivot ball.

With regards to the TOB's being shown, I see an OEM TOB and what looks like an ACT or aftermarket brand like a Nachi TOB. Measure the mounting height vs the contact height of the TOB and the surface diameter of the engagement surface that contacts the pressure plate fingers. Where is contacting the fingers at the tips or further outwards? Not all TOB's have the same dimensional range for contact height or contact diameter and it does matter. Also, let's say there is already a problem with the clutch itself from being over-adjusted, or not enough disengagement range (flywheel step height issue) from the fingers being too flat, or damaged fingers/diaphragm spring that are pressed in too far, or if there are damaged release straps on the pressure plate. All of those things will cause disengagment issues.

In your case, the fork is maxed out and the TOB is maxed out going towards the clutch. Why? Is it a pressure plate issue? Is it a flywheel step height issue or friction surface warpage issue? Is it a release strap issue or damaged pressure plate diaphragm spring? Bent clutch fork? Bellhousing missing alignment dowels? Missing rear M8 mounting bolt through the engine block causing the trans to push away from the block when pushing the clutch pedal? Why do you need to add a metric ton of shims to your pivot ball to offset the clutch fork towards the clutch to get it towards the center point? Have you measured your crank thrust play?

Knowing the disengagement range of the clutch you are working with is helpful as well. Having a fixture set up on a hydraulic press, and measuring the distance needed to disengage the clutch disk would then correlate to how much range you need for the clutch fork to move the TOB to disengage the clutch in-car. Then measuring what the distance is from the fulcrum point on the fork to the TOB centerline vs the fulcrum point to the slave cylinder dimple to calculate what you actually need for fork movement. Kurt has made a few videos if I recall specifically discussing this. @bastarddsm do you have any links you can share to those videos you made in the past?

These measurements were quick eye-ball's with a trans I have on the bench using a new OEM TOB, clutch fork and pivot ball. Everyone may have slightly different numbers.
3.54" fork fully towards the bellhousing (measuring from bellhousing flange to clutch fork slave dimple) - minimum range
+0.419" TOB bottomed out away from clutch (tip of TOB sleeve to TOB contact surface) - minimum range
1.20" fork fully away from the bellhousing (measuring from bellhousing flange to clutch fork slave dimple) - maximum range
-0.215" TOB maxed out towards the clutch (tip of TOB contact surface to TOB sleeve) - beyond maximum range
So, measuring the clutch fork from the TOB clip holes to the center of the clutch fork pivot ball hole where the ball actually rests inside of it, I get around:
~2.4" pivot center to TOB center
~4.2" pivot center to slave center
which is ~ = 1.75:1 ratio of movement of the slave push vs the TOB movement.

2.3" of total fork range of movement
to
0.635" of total TOB range of movement (with trans out, not in contact with a clutch; you would have to measure that in-car of the fork range with the slave cylinder off by actuating the fork in both directions and measure.)

So the maximum range of the TOB is ~1.11" of fork travel with no pivot ball shim installed.
There is no way you would see a need for this amount of disengagement range from the fork / TOB for any clutch out there. Typically you should be able to get around 3/4"-1.0" of slave travel (fork movement from pedal up to pedal fully down), which would give you 0.43"-0.57" of TOB actual movement.

That is why it is useful to measure the range needed to disengage the clutch on the hydraulic press to set up your clutch hydraulics to move the TOB / fork the amount you need and then you can gauge if you have enough clutch hydraulic displacement and movement of the fork to push the TOB the correct distance to disengage the clutch.

Again, this isn't rocket science, I free-handed these measurements. Take your time and do the actual measurements for your application.

Another consideration was touched on before regarding a bent hub clutch disk. This is a common occurrence and you wouldn't see it visually unless you had it spinning and measured the axial play on a fixed shaft. The problem also is that your worn input shaft tapered roller bearings in the transmission are likely under bearing end play which will cause axial movement resulting in the disk oscillating as well which can cause a clutch drag issue.

In this circumstance though, I am pointing towards a crap pressure plate, too little step height, a bent clutch fork, a worn clutch fork pivot ball pocket, a worn clutch fork pivot ball, worn clutch fork fingers where the TOB rests, a damaged TOB or one with not enough height for the application. Other factors externally if the fork was in the proper engagement range offset center to center right of the clutch fork inspection window that would cause less than ideal disengagement range for the clutch hydraulics would be weak or pressure bleeding clutch hydraulics, crap brake fluid or moisture in hydraulics, a bleeding inner piston seal on the clutch master cylinder, or a bleeding piston seal or damaged bore on the clutch slave cylinder, a crap hydraulic line / system, or worn/damaged pedal assembly, and excessive crank thrust play. Those are all things to think about.

Also, there is no darn need to rev the piss out of the engine to 7000rpm to see clutch drag, you likely have crank thrust play or axial movement of the input shaft / clutch disk or a loose clutch hub causing it to drag as well. This is the problem with used parts and lots of variables. Remove variables one at at time.

Good luck!

 

[Ludachris]

Well, I see a lot of used parts for clutch forks and TOB's, how about doing some measurements of the clutch forks, measuring the thickness of the fork fingers that the TOB rests on, measuring the pivot ball pocket depth and visual wear, visually inspecting the retainer clip that it is flat and tight on the pivot ball. Grab a pivot ball and put it in a vise, mount a clutch fork to it, and see if it has any in/out movement at the pivot ball that will cause slop and pulling out of the fork from the pivot ball. With regards to the TOB's being shown, I see an OEM TOB and what looks like an ACT or aftermarket brand like a Nachi TOB. Measure the mounting height vs the contact height of the TOB and the surface diameter of the engagement surface that contacts the pressure plate fingers. Where is contacting the fingers? at the tips or further outwards? Not all TOB's have the same dimensional range for contact height or contact diameter and it does matter. Also, let's say there is already a problem with the clutch itself from being over-adjusted, or not enough disengagement range (flywheel step height issue) from the fingers being too flat, or damaged fingers/diaphragm spring that are pressed in too far, or if there are damaged release straps on the pressure plate. All of those things will cause disengagment issues. In your case, the fork is maxed out and the TOB is maxed out going towards the clutch. Why? Is it a pressure plate issue? Is it a flywheel step height issue or friction surface warpage issue? Is it a release strap issue or damaged pressure plate diaphragm spring? Bent clutch fork? Bellhousing missing alignment dowels? Missing rear M8 mounting bolt through the engine block causing the trans to push away from the block when pushing the clutch pedal? Why do you need to add a metric ton of shims to your pivot ball to offset the clutch fork towards the clutch to get it towards the center point? Have you measured your crank thrust play?

Knowing the disengagement range of the clutch you are working with is helpful as well. Having a fixture set up on a hydraulic press, and measuring the distance needed to disengage the clutch disk would then correlate to how much range you need for the clutch fork to move the TOB to disengage the clutch in-car. Then measuring what the distance is from the fulcrum point on the fork to the TOB centerline vs the fulcrum point to the slave cylinder dimple to calculate what you actually need for fork movement.

These measurements were quick eye-ball's with a trans I have on the bench using a new OEM TOB, clutch fork and pivot ball. Everyone may have slightly different numbers.
3.54" fork fully towards the bellhousing (measuring from bellhousing flange to clutch fork slave dimple) - minimum range
+0.419" TOB bottomed out away from clutch (tip of TOB sleeve to TOB contact surface) - minimum range
1.20" fork fully away from the bellhousing (measuring from bellhousing flange to clutch fork slave dimple) - maximum range
-0.215" TOB maxed out towards the clutch (tip of TOB contact surface to TOB sleeve) - beyond maximum range
So, measuring the clutch fork from the TOB clip holes to the center of the clutch fork pivot ball hole where the ball actually rests inside of it, I get around:
~2.4" pivot center to TOB center
~4.2" pivot center to slave center
which is ~ = 1.75:1 ratio of movement of the slave push vs the TOB movement.

2.3" of total fork range of movement
to
0.635" of total TOB range of movement (with trans out, not in contact with a clutch; you would have to measure that in-car of the fork range with the slave cylinder off by actuating the fork in both directions and measure.)

So the maximum range of the TOB is ~1.11" of fork travel with no pivot ball shim installed.
There is no way you would see a need for this amount of disengagement range from the fork / TOB for any clutch out there. Typically you should be able to get around 3/4"-1.0" of slave travel (fork movement from pedal up to pedal fully down), which would give you 0.43"-0.57" of TOB actual movement.

That is why it is useful to measure the range needed to disengage the clutch on the hydraulic press to set up your clutch hydraulics to move the TOB / fork the amount you need and then you can gauge if you have enough clutch hydraulic displacement and movement of the fork to push the TOB the correct distance to disengage the clutch.

Again, this isn't rocket science, I free-handed these measurements. Take your time and do the actual measurements for your application.

Another consideration was touched on before regarding a bent hub clutch disk. This is a common occurrence and you wouldn't see it visually unless you had it spinning and measured the axial play on a fixed shaft. The problem also is that your worn input shaft tapered roller bearings in the transmission are likely under bearing end play which will cause axial movement resulting in the disk oscillating as well which can cause a clutch drag issue.

In this circumstance though, I am pointing towards a crap pressure plate, too little step height, a bent clutch fork, a worn clutch fork pivot ball pocket, a worn clutch fork pivot ball, worn clutch fork fingers where the TOB rests, a damaged TOB or one with not enough height for the application. Other factors externally if the fork was in the proper engagement range offset center to center right of the clutch fork inspection window that would cause less than ideal disengagement range for the clutch hydraulics would be weak or pressure bleeding clutch hydraulics, crap brake fluid or moisture in hydraulics, a bleeding inner piston seal on the clutch master cylinder, or a bleeding piston seal or damaged bore on the clutch slave cylinder, a crap hydraulic line / system, or worn/damaged pedal assembly, and excessive crank thrust play. Those are all things to think about.

Also, there is no darn need to rev the piss out of the engine to 7000rpm to see clutch drag, you likely have crank thrust play or axial movement of the input shaft / clutch disk or a loose clutch hub causing it to drag as well. This is the problem with used parts and lots of variables. Remove variables one at at time.

Good luck!

Well there's plenty to chew on.

 

[Tony J]

Tim you sent me a wicked email about some clutch setups you have, and I'd like to buy some but I want this drag issue fixed before I spend some money.

The car was shifting like butter before I broke my assembly with an act2600.


That being said i pulled that clutch went back to the butter one and have had drag issues since welding pedal assembly.

Which led me to pull the assembly again and re weld it.

Replace master and slave. Still wasn't getting full disengagement so that's why I pulled trans.

I have been sent the VIRAL Pic of the fork in the window with the red lines. My fork based on that Pic needed shims.

I had another trans with 2 shims behind the pivot ball, a diff throw out bearing and fork. I took all 3 parts and put it on my trans.

Haven't buttoned the front end up yet. Been on daddy duty last 2 nights.. I hope to get out there soon today and wrench on it.

I do believe my slave and master are working good. I get 5/8 to 3/4 of slave travel. Before the shims, when pushing clutch down at floor it felt like fingers are barely being pressed.

Now it feels like it has that ooomph at the bottom to really disengage fully even tho I'm still on the floor .

If these shims don't improve anything I do have another clutch and pp to try but they are stock and quite literally the exact parts that are in my trans right now.

Tony.