Clutch Engagement/Disengagement

[4g63dreams]

I recently had a clutch problem in which my car would severely change my clutch pedal from soft or ok, to VERY hard to press after a few mins of being running.

So I brought it to a mechanic who had never messed with DSMs, but this was a good thing because it allowed me to learn more, hopefully this helps anyone else having the same problem as we looked over everything we possibly could. About 900 dollars later we found the culprit. And now I'm back to my old learning how to drive stick youthness.

Clutches are a hydraulic system.

I'm not trying to school anyone. But thats an obvious fact. Which tells us that they work with fluids and pumps.

Our pumps are the Clutch pedal, Master and Cylinder Slave, and Pressure plate (if i'm not mistaken, because the PP pushes back out) THese are also in working order. in between each of these components of our vehicles are the lines. we have 3 main kinds: metal, braided stainless steel, and rubber.

what these lines connect to is the transmission. which inside houses the clutch disk, PP, fork and throwout. these things connect to the input shaft, and that connects to everything that i have yet to learn about but the main part here I have already mentioned.

If you purchased a car that is having the engage or disengagement issues the above parts are your main concerns. I would advise to bypass the clutch oil fluid chamber (located at the between master and the slave, just before the transmission) this means there are less "housings" to cause problems, and the part is discontinued in newer models... I personally couldn't see a reason for it.

now that its gone, you should replace any OLD rubber hose you have associated with the transmission of fluids in your whole system. The problem mine had was that the hydraulic hose connecting slave to transmission was expanding as the temp rose and once i pushed liquid into it it wouldn't let it back out fast enough effectively leaving me engaged the whole time.

replace both master and slave cylinders. and replace your forks and pivot balls everytime you resurface a wheel. this gives you optimum throw (i think thats what its called) and you dont have to worry much about shimming if fork and ball are newer, at least... if you do, then you should shim the same amount that was shaved off the fly! or a bit less but this is to keep everything at optimal working distances.

(please mind me, its 438 am and i had a few beers, but this REALLY helped me)

replace your clutch disk, pp, and throw out! also check and see to make sure that your disk doesn't SEIZE onto the input shaft! it should be able to slide effortlessly on it (minimal to no grease, you dont want that stuff on your disk pads)

At the moment you should have replaced most of the components involved in the problem. The clutch Hydraulic hose that was my culprit was 10.5" long. When I wake up i'll post the proper vids (they aren't mine) and page (not mine either) which helped me alot in this crisis.

I hope this helped because i read about a few people tearing their cars apart because of this matter. Stick with the basics, before you drop your tranny, check that one hose specifically, check your lines, make sure no leaks liquid or air, and chake cylinders. Check pedal too. if nothing then drop the tranny and do as you please, but make sure you check the disk and input shaft smoothness, and that you align your clutch set correctly.

Bolts not torqued onto the tranny itself can cause problems and always use a locktite type of compound to prevent vibrations from loosening those up.

happy thanks giving and goodnight guys!

 

[bryanwheat]

So you paid 900 dollars to replace a hose? Sounds like the shop dove in and started replacing parts not knowing quite what they were doing.

 

[4g63dreams]

That 900 is steep i agree, but i more than happily paid it total to get a first hand look at how everything was working n responding.

While replacing the obvious, it also taught me the value of checking the small things first. I want to share that lesson though everyone knows it already, and also just to give a "checklist" for those having the problem.

We tend to over look steps looking at a staircase.

 

[emcee]

Having a similar problem

I've noticed it drives fine for 15 min or so, but then when I stop and park like at a store, then start driving again, it starts slipping. After parking it at home, after it sits for an hour, it drives fine again. So, it acts like some pressure is builds up, makes it slip, then when that is relieved, it works ok.

I had a minimal leak in the master cylinder, in fact, like drops per month, and lived with it for 5 years by just bleeding it every 3 months. Finally decided to replace it,... wish I just lived with the leak. Replaced the master and slave cylinder and used the 'how to bleed video" on this site (below), readjusted several times, replace the clutch and throw out bearing, still same slipping.

I am now looking at the Clutch Fluid Chamber that sits between the master and slave. Wondering what this is for, I read on another site that it was designed to make the shift smoother for daily driving... makes sense, and inline damper with fluid. Mitsu discontinued it and seems the common solution is just remove it and go straight line.

fyi, here is a good vid from this site that I found helpful. Mc

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[mercaholik]

I'm confused, if your clutch is slipping the hydraulic system wouldn't be to blame. The pressure plate applies force to the friction disk. Either there is a contaminant on the clutch disk, or the friction material is worn. I would think that if the p/p fingers where broken or damaged it wouldn't be intermittent, but you may want to remove the flywheel inspection cover and check for fluid leaks. If somehow pressure wasn't being released when the pedal is then maybe, but I've yet to hear of that.​

 

[emcee]

When you press the clutch pedal it pushes the hydraulic fluid to disengage the clutch. So for example, if you push it halfway and its only halfway disengaged, its slips. Conversely, if the system has air in it so it won't push the fluid, the pedal is soft and the clutch won't disengage.

What seems to be happening in mine is pressure is building up in the lines somewhere after 15-30 minutes of use which then is keeping it partially disengaged so it sliips. Since I have already replaced the Master and Slave cylinders and the clutch and throw out bearing, the only thing left is the Clutch Fluid Chamber that dampens the engagements or some trash in the line. Replacing the Clutch Fluid Chamber next week. Mc

 

[mercaholik]

I understand the concept but in reality I've never heard of our seen this cause the clutch to slip. But if the rubber clutch hose broke down on the inside and piece of rubber acted like a check valve that I saw once but it was a brake hose. But that was one in a million I think. Either way 86 that fluid chamber and go from there, hope that solves it. Let us know what happens.