bigmackloud

So I was having the standard clutch pedal sticking to the floor issue with my 01 C5. All the reading I did indicated the Tick clutch master cylinder was the cure-all, so I decided to give it a try.

While it does seem better, I'm still having a problem. though it's really only noticeable at the track. typically it happens at the end of the back straight at VIR, where I'm topping out 5th gear. I have enough clutch to get out of gear but not enough to downshift into 4th. (Luckily there wasn't anyone behind me as I coasted down roller coaster). But it doesn't happen every time; just some of the time.

I drove the car to work for a week after the install, and then 5 sessions for the track day. No change in the clutch fluid level so I don't think there was any sort of air pocket. Certainly no leaks. and any other time I have good clutch pedal pressure.

Tick didn't have many suggestions when I called. Appears to be heat related? I suppose I could put even more heat shielding on the line, but the Tick line is braided ss with a heat sheathing already. The brake lines running to the back are in the same area near the headers, so if it were boiling the clutch fluid, I would think it would boil the brake fluid too (same fluid, ATE Type 200).

I removed the factory clutch pedal assist spring (actually it was already broken).

I'm thinking about trying the Lingenfelter return spring kit but figured I'd see if there are any other suggestions before I throw money at the problem.

Thoughts?

froggy47

Put the stock spring back AND add the Lingenfilter kit. That's how mine is with original stock clutch master & slave.

Lingenfilter knows what they are doing, ya think?



Pedal will be a little stiffer but not bad. I do keep the fluid fresh.

0Anthony @ LGMotorsports

Since you have a C5, pull the lower bell housing inspection cover and check the slave when it does it if you can. Might be the slave cylinder.

bigmackloud

I have no doubt that Lingenfelter knows what they are doing, and I'll likely end up ordering their kit. But the return spring just seems like a work around to whatever the actual issue is.

Ive read theories that the pressure plate fingers aren't strong enough to push the pedal back. But I can't quite wrap my mind around that. All of the pressure should be working with the pressure plate fingers. Where is the resistance coming from that's preventing the pressure plate from pushing the pedal back up?

And what's further, my issue is that I can't get back into gear. Which would suggest that the clutch is actually dragging enough that the synchros can't mesh to allow me into gear. It's not getting stuck completely disengaged. If that were the case, I'd be able to get into gear but not accelerate.

And unfortunately this only happens under severe conditions. It's rather hard to recreate on public roads and not get arrested, haha. And by the time I get back to the pits, or my garage, the condition has gone away and everything is normal again.

Not sure if it adds much, but I also noticed that occasionally, again at high rpm (say shifting from 4th to 5th), that the clutch was much harder than normal to press in. But again, it didn't always do it.

froggy47

I am going out on a limb here as I am not an engineer. It's not the strength of the pressure plate fingers, it's the angle that they get into (only on high rpm shifts). They get bent/positioned the wrong angle so that they are actually holding (with all their power) the clutch PEDAL DOWN to the floor instead of pushing it back up. The stock spring PLUS the Lingenfelter assist spring over come the issue (caused by a poorly engineered oem system) and pop the pedal back up in spite of the resistance the fingers are putting up (at the bad angle).

I would hope someone from Lingenfelter could confirm this, but I don't know if they are on this forum much.

Joshboody

I don't get a sticking pedal, but do get a "light" pedal and change in engagement point after high rpm 2 to 3rd shift... it kinda screws up my h/t but goes away quickly. I normally short shift because of it.
Its baffling what's going on, but seems something with the PP fingers... takes less effort and not returning to normal position momentarily. I'm just going to deal with it until my clutch goes.

FASTFATBOY

Does the clutch fluid get black really fast?

Make sure the clutch line isn't on the exhaust.

Slave is bad most likely.

AND0

I have a similar sort of problem. 01 C5Z, inconsistent engagement point of the clutch when shifting specifically at high RPM. Where I drive there is one spot that I have a high RPM downshift 3 to 2 and the trans is balky and the clutch sometimes engages very close to the floor sometimes upsetting the car. Weird.

I don't know if there is some sort of odd centrifugal force acting on the fingers or what, but it creates a very inconsistent pedal action.

I really think the problem is with the factory pressure plate and the real solution is going to be an aftermarket replacement.

I recently switched to the tick master in hopes of fixing the problem, and while it has helped cope with the symptoms, the problem still exists.

The tick master cylinder absolutely makes the clutch pedal much stiffer. The factory cylinder bore is 3/4" and the Tick is 7/8"
This makes the pedal ~36% stiffer. That is pretty significant. In fact it makes the clutch very tiresome to drive in traffic now, and it gives up a lot of feel and touch. The good points are that the clutch is now adjustable where it engages and the tick kit just uses a standard Tilton series 75 universal master cylinder. I can get a replacement with a 13/16" bore for like $80. The 13/16" will flow more fluid then the OEM and be only 18% heavier