Sticky clutch after heavy braking

[Alphius]

Yes, now that you mention it I think it is more likely to occur on a downhill on my car as well. Part of my drive to work is a steep hill with stoplights, so in the morning I drive down it and in the evening I drive up and it is definitely easier to cause by braking downhill. I always chalked that up to simply having to brake harder going downhill though...

Regardless of that, it hardly ever happens unless I panic stop. My reservoir is filled to the brim but it's cut quite a bit so that only means that I have a very small amount in there anyway, maybe half of the stock capacity?

[Legacy777]

Even half the capacity should be good enough, but that is an interesting thought about air getting in under heavy braking.

Just curious, do you guys have the damper still installed in the line?

[LikeUCare]

I still have the damper, I thought about dumping it to see if it helps.

This has happened to me accelerating hard uphill as well.

[Alphius]

It's never happened to me accelerating uphill. And I accelerate uphill often at 18psi.

Sounds like his issue is a little worse than mine but very similar.

My clutch damper is removed.

[LikeUCare]

Okay, I am going on a different track here. I am almost positive this issue is in the pedal assembly. So sure that I just spent $35 on ordering 4 tiny ass bushings and a spring for the brake pedal.

So here is the theory. I have bad bushings in either the "Boss Comp" assembly ends (common pivot for brake and clutch pedal) or the brake pedal itself.

Normal operation equals no issue but really standing on the brake pedal compresses and makes the bushings bind up on this common linkage. After a couple of pumps (where we think we are getting air out) the bushings frees back up and normal operation is returned. This coupled with a brake return spring (shared with clutch pedal pg 460 of parts manual) that has 232,000 miles on it and is feeling its age we have our intermittent, while hard braking issue presenting in the clutch.

I will have to wait a week on parts to test my theory but in the mean time I am going to try to mitigate by lubing up the bushings and trying to wedge something in between the spring and its holder to make the spring travel less.

Will let you know my findings, I hope this is it, as this clutch pedal is really starting to annoy me.

[Alphius]

It will be interesting to find out what the results of this are, mine is not bad at all but every once in a while when it occurs it is a little annoying.

My brake/clutch assembly has over 250,000 on it, so you may be onto something.

How would you explain being unable to cause the problem at a standstill by really laying on the brake pedal? It seems like high g-forces in a forward direction are the main contributing factor in this.

[LikeUCare]

Alphius, try this:

Get under pedal assembly and WD40 the crap out of every piece that looks like it moves. (I know...I know......WD40 is a cleaner and can break down my pristine 18 y/o rubber bushings)

Loosen the clutch adjust screw almost all the way out on your clutch assembly. When I did this raised the engagement point almost to top of pedal.

Go out and stomp on it and slam brakes. I am interested to see if that does it for you.

Here is what I found on mine, clutch assist spring A was binding up (pg 460 parts manual). With previous adjustment settings it wasn't allowing the spring to cycle all the way top and I suspect the MC was getting it the rest of the way. When I was hitting the brakes hard the amount of sag I was seeing in the pedal was equal to where the spring was binding at. ( I still don't have a good explanation for this)

Before when I pressed on the clutch lightly with my hand I could feel a "catch" at the point the spring started providing resistance. It was about 1.5-2 inches down the stroke. With the WD40 to the spring and associated bushings it smoothed this out. Adjusting the clutch higher up the pedal eliminated this catch completely and let the spring operate without it hitting its operation limit.

Currently I haven't had any sagging of the clutch with hard braking with this in fix in place. I am going to adjust the clutch pedal back down in little increments to get the engagement point lower without getting back to the point where that assist spring is overextended.

Give it a try, curious if this helps you out as well.

[Legacy777]

Sounds like you found the problem. When I did my 5mt swap I adjusted the clutch pedal up so it's pretty much even with the brake pedal. So it's likely further up than the stock position.

[Alphius]

My clutch pedal is already at the point where there is maybe 1/2 inch freeplay at the top. I adjusted it that way a few months ago to minimize this problem. (And cause that's where I like it. ) Maybe that's why mine hasn't been as bad as yours from the start?