Clutch is slipping/ Ideas?

[GSEclipse620]

Hi everyone. For quite a while I've been having some clutch trouble in my 95 gs. It seems as time passes it will start engaging less and less and right now it is slipping a bit. It will go away once i bleed the system and she will engage hard and low ( only like 4k on clutch). Over the course of trying to find the problem i have gotten rebuild kits for the slave and master cylinders and polished all of the areas where it seals. I think that there is a leak somewhere and air is getting in or something but where as I have already rebuilt both cylinders I'm not sure where I should look next. If anybody has an idea on where to look next that would help, Thanks!

The problem seems to come and go a little bit. Yesterday my clutch was slipping pretty bad in the afternoon but it was fine in the morning. I took my car in town earlier today and it was fine on the way there but slipping on the way back,, it looks like the car has to warm up before anything happens. But for the most part it gets worse over the period of a month or two before I have to bleed it again.

 

[VelocitàPaola]

I don't think air getting into the system has much to do with the clutch slipping. The hydraulic system is only there to disengage the clutch. The system is naturally engaged due to the spring diaphragm. So, air getting into the system would only hinder disengagement (i.e. whenever you push in to shift gears).

If it's been slipping, and it's been getting progressively worse, I'd bet you just need to replace the clutch itself. You can get an OEM clutch for relatively little now.

 

[BigRand]

+1 with paul suggestions.

if your looking for aftermarket my suggestions are

Any Southbend clutch

Spec Clutches Stage 3 and above, (I especially recomnend the Stage 3+ with the street disc)

 

[95TalonOwner]

Taken from a thread from a couple days ago:

The symptoms you're describing sound very much like pedal pump up. Here's the write up directly from RRE's web page:

2G Pedal "Pump Up"

If you are fighting an inconsistent pedal adjustment in a 2G, adjust the upper pedal stop adjuster so that you gain additional free play at the top of the pedal travel. If this is your problem, you will notice that the pedal suddenly gets very tight and the release point will suddenly move up a lot, this is the cause.

2Gs need free play at the top of the pedal travel. If it is close to no travel and right on the edge, then it pumps up. Only 2Gs have a relief valve in the master cylinder that needs to be uncovered so fluid can go back into the reservoir on the clutch release. If not, it gets tighter and tighter and tighter. Then it may slowly relieve the pressure and it is back to normal. Just a 2G thing. You need more free play at the top of the pedal travel.

Left unchecked, the pedal will pump up more and more. The clutch will begin to slip since it is as if you are driving around with your foot on the clutch pedal. Also it plays hell on the crankshaft thrust bearings. The constant pressure pushes the clutch release bearing onto the clutch and flywheel. When centrifugal force throws the clutch release fingers outwards, they make additional pressure on the thrust bearings of the crank. This is an additional factor in short lived crankshaft release bearings and an additional potential cause for crankwalk.

Basically, you want to adjust pedal travel down and to do this, loosen the jam nut on the slave rod. Turn the slave rod counterclockwise one or two turns, tighten the jam nut and see how it feels. Keep in mind that when I say counterclockwise, you should be looking at the rod as if you were sitting in the driver's seat. In case you get confused, here's a link to the article:

http://www.roadraceengineering.com/clutchandflywheeltech.htm

It's a five minute fix so have at it.

Andy

 

[VelocitàPaola]

Taken from a thread from a couple days ago:

I don't think that has anything to do with his situation...

 

[95TalonOwner]

It wouldn't hurt to try it. It's quick and easy.

 

[VelocitàPaola]

Yeah, but I don't even think it really applies... our clutch set ups are different than 4G63s.

 

[95TalonOwner]

Well thanks for that info. The clutch and tranny is probably one of the only things I haven't had to touch on my car yet.

 

[TalonESIT]

+1 with paul suggestions.

if your looking for aftermarket my suggestions are

Any Southbend clutch

Spec Clutches Stage 3 and above, (I especially recomnend the Stage 3+ with the street disc)

When you refer to the Spec clutches are you talking about the whole modular clutch assembly? Or did you convert to a non-mod?

 

[bullettdsm]

I warn you once. STAY AWAY FROM SPEC CLUTCHES! Words of experience that I just fixed after wasting good money on a Spec 4 sprung. I thought that they had no problems but within 3000 miles my clutch started sounding like a bag of springs. At 6k I had to take it out because it could not No-lift-shift anymore. There are others who have had problems. IMO Spec now sucks! I'm very unhappy with them. Go Southbend.

MB

 

[GSEclipse620]

I'm pretty sure that I don't need to replace the clutch. I just did that a while ago and it can't have more than 10k on it if evan 5. The problem will go away for a while once i bleed the system and after i do that it engages as good as I have ever felt it. Usually when i take her out after I bleed it I'll snap my neck back a bit. Once the car warms up it gets worse, when i first start up in the morning it's fine and doesn't slip.

 

[GSEclipse620]

Hi everybody,, just an update. I bled the system out a couple days ago and it was engaging nice and low like it should. But on the way to work today I was going 20 or so and double clutched to get down into 1st. Imedietly after that my clutch started slipping, bad. I could dump it at just over idle w/ just a little gas,,, a LITTLE gas, i could barley accelerate, and I had to drive all the way to work and back. It seems to jump from really good to really bad if i do any hard shifting or quick clutch work ( quick shift to 2nd/double clutching)I'm going to bleed it out tomarow morning and I'm sure it will be fine again, for a while. But this is really starting to be a pain in the a$$! If anybody has any other ideas, anything at all, feel free to throw them out! Thanks!

 

[BigRand]

When you refer to the Spec clutches are you talking about the whole modular clutch assembly? Or did you convert to a non-mod?

I didn't convert...

after some hard beatings on the clutch it still holds up like a champ.

I can't say the same for the stage 2's or anything else. Strictly speaking about the stage 3+

 

[DSMcrazy3]

There is a flaw in the clutch. Obviously. Not the clutch system, the clutch. It's good in the morning because it's cold and hasn't had any wear for X amount of time. Once you've driven on it for alittle bit it's got wear and has heated up, allowing it to slip. Same thing happened to me.

 

[GSEclipse620]

I don't see how that could be triggered all at one time though, This morning It happened all at once, with that double clutch to first. Right before that it was grabbing as hard as i have ever felt it ( when it's good, it's great) but imedietly after it was slipping so bad i couldn't stall it if I wanted to.
"Not the clutch system, the clutch. It's good in the morning because it's cold and hasn't had any wear for X amount of time."
This makes sence because I just rode back from my friend's house. There was no slipping at all, but it hasn't had as long to cool down (3:30 am) and it wasn't engaging as best as I have ever felt, but no slip. This would be consistant w/ the theory that it engages better when cold since it would be probably still luke warm ( parked the car at my friends house at approx midnight after coming home from work two towns over, ) But it doesn't make sence w/ the change happening drastically all at once like this morning. None of my symptoms seem to point to one specific thing which is what is frustrating me, and I don't want to jump to the conclusion that it's a problem w/ the clutch itself. It was a solid weekend to change that mother and I don't want do it again,,, any ideas more promising?

 

[BigRand]

I don't know how many miles you have on your clutch, but it just sounds like disk on the clutch is at the end of its life spand. And sooner or later it will start slipping when its cold as well.

This probably has nothing to do with it at all, but have you checked your brake/clutch fluid lately, or maybe the lines leading to the clutch? Have you ever bled te clutch?

You might want to give that a try, as brake fluid is fairly in expensisve should it be the problem. But I will admit it sounds more like a OEM clutch just getting ready to give.

 

[bullettdsm]

Ok just to cover a few bases;
Not that I suspect it but when you bleed, do you see any air bubbles?
Is your pedal returning to full position with the same force everytime?
Do you have a modular clutch in there, or was it reverted to non?
If non, did you change just the disc? Was the surface of the flywheel OK?
When it's cold and engaging, put your car in first gear, put your foot on the brake and slip the clutch (please be careful). Does it stall right out, or is it able to pull through some? (wait, nevermind that one. I just re-read and it looks like you say it engages hard and low)
What exactly is happening to make you say that it is slipping?

Sorry if some of this seems simple but it may help us out.

Also, pardon me for a quick tangent but hey Rand! How many miles you got on that spec? (Plus, looky over to the left at my new time slip! Yup, still NA)


And Talonesit, oddly enough my back up clutch is a spec non-modular. I had to put that on because the stage 4 went. I decided to leave the non mod on there to see what will happen to it.


MB

 

[GSEclipse620]

I just talked to my dad and he went down to the shop to find all the stuff we replaced because he's a nuts packrat. We changed out the disk/pressure plate/flywheel and throw out bearing. We didn't convert anything and put in a stock clutch so I'm guessing it is modular ( what's the difference?)
As for the pedal feel, when it is having it's problems it feels looser down low when it is disengaged and comes up higher than normal, how bad it does either is consistant w/ how bad it is slipping.
What it is doing when I'm saying it's slipping is: say I'm going 45 in 5th at 2 grand, I can step on the gas and rev the car up. The clutch is still clamping w/ x amnt. of force so I'll accelerate but can rev far faster than the car is accelerating. 4k at 50 in 5th doesn't make sence?? When I let off the gas the rpms will return to normal.
Another update; My car sat all morning untill 2ish when i went to the post office. My clutch was slipping, just like yesterday and the day before, but not so bad I couldn't drive it. I took it out of the drive-way and ( my 2nd gear is getting kind of notchy) and I double clutched into 2nd because I was just curious to see if it would go in smoother. Immedietly after, when i let the clutch out when i was into 2nd, it got much worse. It was barley engaging. I put the car in neutral and pumped the clutch for a bit to see if that would make a difference. After that when i tryed putting it in gear again it wouldn't engage at all.
By now I'm a football field away from my house and i just pull off to the side, call my buddy to come help me bleed it ( luckily I always keep an adjustable wrench in my car because it's completly unreliable and happened to find an old, beat up bottle of brake fluid under the passenger seat so I didn't have to go to my house and back on foot, haha). So my friend shows up and we bleed the system. Get back in, start her up and it's fine.
The point of me telling you this is because this rules out that it slipping is temperature related or that it is a flaw in the clutch itself. The car didn't have time to warm up within a football field.
P.S. Those are some fine numbers for n/a bulletdsm! Nice.

 

[BigRand]

as for miles on the spec 3+ clutch....lets see

127 000 when the motor went in with the new clutch.......141ish now

14K ish

 

[GSEclipse620]

Hey guys,,, Me and my dad were talking about it and the only other thing that we can think of is that little plastic peice on top of the master cylinder. What is this? We were thinking it is some kind of filter. It is the only other thing we could think of. Does anybody know exactly what it is there for? Could it cause my problem if it had gone faulty?

 

[GSEclipse620]

Hi,, just updating this post for anyone that might search and find this thread dealing with the same problem. I just cut and pasted the rest from another thread I posted concerning this problem.


Originally Posted by bryanwheat
"To anyone that said anything about bleeding the system. AIr in the line has nothing to do with the clutch not grabbing, if there were air in the line, than the clutch wouldn't disengage right.

Now here is your problem. Your clutch pedal rod is adjusted too tight, it is not releasing all the way, there should be an ammount of freeplay when the pedal is depressed. IF you don't allow for this, and are driving it hard, and doing some fast clutching, than the pressure plate son't be able to release all the way, because the master cylinder isn't able to release all the pressure. You need to get under the dash, and adjust that rod. "

EXACTLY!!! I wish I had checked this because I didn't see this post until I came back to update tonight. We ordered some more random parts from Mistu and were just putting them in tonight at the shop. We got a new hose that goes from the resevior, the plastic peice on top of the master that the hose connects too and a new clamp that holds that peice to the mast. (In retrospect I don't know why we thought any of those parts would help but we were basically just throwing parts at it at this point.) None of those helped but while we had the Mast. Cyl. out we looked at it extensivley to see exactly how it funtioned.

In the plunger there is a one way valve on the output side of the cylinder. There is a slot cut out of the plunger for a rod that goes through the master cylinder. This rod is fixed and is set up so that when the clutch is engaged (foot off pedal) it presses against the valve opening it up and letting fluid travel back up into the resevior. There is a rod that connects the plunger to the pedal by means of a bracket. The rod is skrewed into the bracket. What we did was just give the rod another half turn bringing it back towards the pedal a bit. Thus bringing the plunger back towards the pedal a bit. Now the valve is hitting the rod (the first one,, the one inside the master cyl.) better and is letting all of the fluid back.

What was happening before was the inner rod wasn't coming into contact with the valve enough to let all of the fluid back into the resevior, keeping pressure in the system and keeping the clutch disengaged to varying degrees. It is obviously kind of finicky and there is a margin of error since it varied from time to time.

Now the pedal has a different feel to it. The half turn did a lot more than I thought it would. My clutch engages about a 1/2"-3/4" off the floor and I have much more free play at the top. I just say this to warn you that adjusting the rod is somewhat sensative and if you do it too much you might not disengage completley and grind gears. I probably only needed a 1/4 turn but what ever,, it works. I drove it moderatly hard on the way home to test it out and did a lot of double clutching around because that is what usually sets it off and it felt fine after about a half hr. ride so I'm conviced that I've finally won