mushy clutch pedal after hard driving
 

When I take my car out for a spirited drive, the pedal gets mushy, and at about 20% pushed in, it's very loose, almost like air is in the line. it sometimes won't even come back up once it gets to that 80% out point and I have to pull it with my foot.

This usually happens let's say I go 0-100ish or just do a lot of high rev shifting.

I believe this is a known problem, and the only related search I got was a thread from 2002 so I didn't wanna bump that up.... Some people have said it's the master cylinder/slave and I need to get one that's made by TIC or something?

Thanks!

This is very common with the stock hydraulics. It will only get worse with time, especially if you drag race the car. A Tick Master cylinder will cure the problem once and for all.

Jimbo

so that guy was right...

and is it an easy install? I don't have access to a lift that easy, so most of my work that's done uptop, I can handle usually...

eta: apparently the front wheels need to come off and also the clutch pedal. sounds like some serious PITA to install. the DIYs are there, but all the picture/diagrams are missing in them... people need to learn to use imageshack. lol

http://www.tick-performance.com/tick...dy/hydraulics/

Might as well add a remote bleeder while doing the master.

and here's a post on installation:
http://forums.corvetteforum.com/c5-t...r-install.html

damn, that's the one with the missing pictures =/

pics would help alot

Go to Z06vette and do a search for "tick install". I'm sure Paul's pics are still there.

Jimbo

I had a hell of a time getting the clutch pedal assembly back together. There's three nuts to reattach that're close to impossible to reach. I recommend removing the driver's seat for a little more room. There's other areas of the install that're difficult, and I had the drivetrain out! It helps to be very limber/young, or have help that is.

Thousands of Corvette owners have cured or avoided pedal issues entirely without installing an aftermarket part. Changing the master is certainly not the place to start.

First step is watching this video.

Now, inspect the clutch fluid and tell us what the reservoir looks like.

Next, tell us what are the mods on your car.

Ranger

I have no problems at all with the stock hydraulics, and I'm not easy on the car. I do, however, regularly change out the fluid with ATE super blue. Works like a charm. My guess is you have old/bad fluid, like Ranger suggests, and you don't need to replace the stock bits.

If pristine clutch fluid (by swaps of the reservoir at a cost of about $10 and an hour's time) doesn't give you a normal pedal, then the next step is to change out just the master cylinder to the latest part number for your VIN. The cost of that part is around $100 and two hours or less self-help labor. You just need the part and the pages from the shop manual.

Ranger

fixes
 

:thumbs:

FYI, a new M/C and slave, to the latest PN, didn't work on my setup even after hours of bleeding via a remote bleeder.

Assuming you have a stock LS6 clutch, it's rated for about 350 rwhp/rwtq, plus 8-10%.

From you profile, we see that you car has the following mods:

B&B Bullets
BPP shifter
ARH 1-7/8" LTS
ARH X pipe w/ cats
P1SC Procharger w/ ECS mount
Alky Control

That's easily 30-40% above the capacity of a stock clutch.

You need to be looking for a clutch properly sized to your mods and aspirations.

Ranger

I had the same problem after spirited driving. My fluid was very dark in color. I started doing the Ranger method each time I drove my car. Within a month the fluid was clear. It stayed like that for 2 years. I often check it. :yesnod:.

Strangely enough the spongy feeling came back a few months ago. My fluid is still clean as a whistle though. I started to do the Ranger method again and after 3 weeks its noticeably less spongy after hard driving. I will continue to do the ranger method until it feels normal again.

Toque

My car in 2006 made 382/361

Last week it made only 345/340

I'm blaming it on the previous owner not taking care of it, but with some work, It'll be back to around 380

so the car makes about 380 at the wheels, afaik it still has the stock clutch

now about the fluid

I did the fluid swap about a week ago with the medium size brake fluid. I used Prestone synth DOT 3 brake fluid I kept doing it until I had clear fluid after 30 pumps.

honestly since I did that, it kinda got worse, I'm worried I got air in the line while I was doing that, but I HIGHLY doubt it...

I'l check the video and do it again.

in your video I see you use Prestone DOT 4 and the GM DOT 4 fluids... why 2 diff brands? do you mix them up? which should I use?

and if I remember right, I used DOT3 in there, but I'm not positive.

I'll do it again and see if it's murky (I did it about 2 weeks ago) if not, I'll let you know.

so should I just get another GM master cylinder, or the tick one that's almost 3 times the cost?

I use Prestone DOT4, widely available including Walmart, for about $2.60 for 12 oz.

Keep changing the fluid after each drive until the fluid stays clear.

If the fluid has never been maintained through its long life to now, the master cylinder seals may be abraded by accumulated clutch dust. I wouldn't conclude that is the case until the fluid is rendered to pristine condition.

Ranger

I now have an ACT twin disk. My issues were not enough disengagement for both this clutch at current power levels and the LS6 clutch when the car was near stock (370rwtq). I don't believe power would have anything to do with the M/C's ability to push fluid from chamber A to chamber B. If you disagree, I'm all ears.

Proper functioning of the clutch hydraulics always relies on a correct installation of the clutch components.

An undersized clutch with inadequate clamping power for fwtq of the motor will slip, producing heat that causes vapor lock in the actuator.

Also clutch dust infused clutch fluid will abrade the seals in the master cylinder and cause pedal issues.

Ranger

Apologies, my post required an edit. The issue was lack of disengagement, especially into 5th gear.