Finally fixed my sticking clutch

[Russ K]

First a little back ground on my sticking clutch. Bought the car new, then added TPIS headers and a SLP 234/228 camshaft. Clutch never stuck. Then added ported LPE heads and their 229/242 camshaft. Clutch still worked fine. Then installed TFS heads, LG G5X3 cam and the LG long tube pro headers. Now the clutch would get soft after a wot 1-2-3 shift. But the pedal never stuck to the floor

So I dropped the exhaust and bled the clutch with DOT 4 brake fluid. No improvement.

In September 2011, I installed a TSP 418 short block and reused my cam, heads, headers & intake. Also installed a Luk Pro Gold clutch and a new Luk slave cylinder. Also installed TPE remote bleeder. Now the clutch would stick to the floor after the WOT 2-3 shift! So I installed a Luk clutch master cylinder, still no improvement.

Next I removed the plastic shields behind the oil filter and the starter. Still not much improvement.
Then removed the clutch over center spring, this prevented the clutch pedal staying on the floor but the trans would grind trying to shift into 4th gear as the clutch pedal was very spongy, but would pump back up after lifting the throttle.

Then bled the clutch with Motul RBF fluid, still no real improvement.

Finally purchased the Castrol React SRF Racing brake fluid from Doug Rippie Motorsports. Talked to Randy about my sticking/soft clutch pedal. He said they don't have sticking clutch issues as they always use Castrol React SRF Racing brake fluid in every clutch job.

Well I just finished bleeding out the Motul fluid with the Castrol. Now I can go WOT 1-2-3-4 and while the clutch is a bit lower after the 3-4 shift, I can still shift into 5th & 6th gear.

Russ Kemp

 

[Riley P]

Holy Smokes!!! I guess my question would be, what is actually causing the clutch pedal to stay on the floor, or what component/part is responsible for returning the clutch back to the top? Is it just that the fluid gets hot and bubbles form?

Glad to hear that you have the problem mostly gone and can use your car again! I still remember getting a ride in your car last summer. Simply amazing!!!

 

[Russ K]

The root cause is overheated/boiling clutch fluid. As there never was a problem for the WOT 1-2-3 shifts. The headers really heat up the hydraulic clutch system, then extra heat of the 418 stroker, thus the need for a higher boiling point clutch fluid.

Removing the clutch pedal over center spring prevents the clutch pedal staying on the floor, but the clutch still won't disengage for the 3-4 shift

Russ Kemp

 

[KenR]

I use Prestone synthetic DOT4 brake fluid in mine. Bleed it with a mighty-vac on my remote bleeder every year. This keeps it working well, otherwise I would experience the dreaded soft clutch as you mentioned. Stock '03 Z06.

 

[Riley P]

Sorry for the totally ignorant question but would it be possible to use header wrap or some other type of heat shield for the lines on the clutch system? I'm assuming not because it's right inside the bell housing?? (Is there still a bell housing on the C5's as the tranny is in the back?) I'm sure you thought of this 9 ways from Sunday but was wondering how to shield the system from the header heat if that is the source of heat or is the heat right from the engine or is it heat from everything?

 

[Russ K]

Already wrapped the clutch line with heat wrap, but the wrapping the headers will cause them to crack.

And the clutch bell-housing gets real hot from the headers and so does the slave cylinder.

Yes the clutch bell-housing bolts to the back of the engine.

Russ Kemp

 

[Riley P]

Cool. Thanks Russ. I didn't know that header wrap causes them to crack!

I'm going to stay away from that stuff!!!