hydralic clutch adjustment

Kevin Murphy · #1 (**permalink**) 12-09-2006, 12:53 PM

I have a Unique cobra that was built in 1994. I just bought it in october and love the car. The clutch releases all the way at the top. Now that the weather has gotten colder, the clutch slips when you get into the throttle. The car only has 4500 miles on it . It's got a 428FE, Tremec 5 speed transmission and a hydralic clutch. It's the first car I have owned with a hydralic clutch and don't know how to adjust it. Any help would be greatly appreciated.
Thanks
Kevin

Tommy · #2 (**permalink**) 12-09-2006, 03:07 PM

Kevin -
Do you have a hydraulic throwout bearing or a hydraulic slave cylinder moving a fork?

LMH · #3 (**permalink**) 12-09-2006, 05:38 PM

Is the rod pushing the fork threaded?
Or is the rod pushing the master cylinder threaded?
Should be some sort of adjustment somwhere in the system.
Larry

Kevin Murphy · #4 (**permalink**) 12-10-2006, 04:25 AM

I'm pretty sure the throw out bearing is hydralic, the stainless steel lines run from the reservoir under the fender, into the bell housing. There doesn't seem to be any adjustment on the rod coming through the firewall. I looked under the dash to see if there was any ajustment there, ( nothing) and you can't really get a look at the rod where it comes through into the engine compartment. I haven't taken the cover off the bottom of the bell housing yet. I'm guessing that's the next place to look?
Thanks
Kevin

strictlypersonl · #5 (**permalink**) 12-10-2006, 04:31 AM

Do you have any free play at all at the pedal, or is it hard right away?
(Discount any mechanical slop in the pedal, of course.)
This page will give you an idea of how they are put together.

Naumoff · #6 (**permalink**) 12-10-2006, 04:59 AM

Really no adjustment. HTOB are self adjusting.
First thing I would do is replace the hydraulic fluid with Wilwood 570 and make sure you flush all the old fluid out with the new. Get two bottles just to make sure you have enough.
If this doesn't help then I personally would replace the pressure plate and clutch disc.
4500 miles is not a lot of miles on a clutch but in a Cobra with many burnouts and the like it is probably worn.

Tommy · #7 (**permalink**) 12-10-2006, 05:33 AM

Kevin -
I'm going to assume you understand the basics of how a clutch, flywheel and throw out bearing work. A HTOB is a piston like device with the back end anchored at the front of the transmission and the front end near the fingers of the clutch disc. When the clutch pedal and master cylinder are depressed, the piston extends, depresses the fingers, separating the clutch disc from the flywheel. As a clutch disc wears thinner, the fingers tend to get closer to the HTOB, making the clutch disengage earlier in the travel of the HTOB. Consequently, the installer is instructed to leave a specific gap between the HTOB and clutch fingers when first installing the clutch assemby. This is to allow for normal wear.

If your clutch is releasing with very little clutch pedal movement, it is possible the clutch disc is worn out. It is also possible the builder did not install the HTOB with the needed gap. In any event, if there is no adjustment at the master cylinder, you are looking at dropping the transmission and bell housing to fix the problem. I agree with Tony that you should expect to replace the clutch at the same time.

There are other things that can cause the clutch to slip. Fluid from a leaking rear engine seal or an overextended HTOB will both do the job. I dropped my transmission many times trying to solve such a problem, and ultimately abandoned the HTOB in favor of an external slave cylinder and clutch fork arrangement. If you search this forum for "hydraulic throw out bearing" you'll find lots of comments about them. Good luck with your car.

Dwight · #8 (**permalink**) 12-10-2006, 06:50 AM

I put 13,000 on a clutch / pressure plate with thousands of burn outs, well maybe hundreds. I spin my tires in first, second and third gear. I do a few burn outs everytime I drive, just ask my buddies. Last winter when I pulled my motor, I check the clutch, plate and flywheel. Some wear on the clutch plate but no wear or signs of abuse on the anything else. I did replace the McLeod plate because I did a little motor work and plan on more tire abuse.

I have pics. We think the tires take most of the abuse not the clutch / flywheel.

Dwight

Kevin Murphy · #9 (**permalink**) 12-10-2006, 03:49 PM

Thank you everyone for all the info. I'm sure i'll straighten it out pretty quickly from all the help. I just hope the weather holds here in Massachusettes so I can take it for a test drive. I don't care about the temp, just the snow, salt, and sand.
Kevin