hupp

My clutch recently started acting up. I was going to take the shark for a spin a couple of weeks ago but I could not put her in gear without significant grinding. This after operating perfect for the six months since the rebuild. One thing to note is that all clutch parts are new - master, slave, clutch pac, black rubber hose, reservoir to barke master grommets and blue hose. In fact the only old part is the small section of tubing between the slave and rubber line.

So I resorted to bleeding the clutch (with power bleed) and performed the "push slave piston all the way in" step. The result, a perfectly operating clutch. One week later - back to grinding! Bled again, working fine. Let her sit for another week and (you guessed it) wont go ito gear.

I have checked all fittings for leaks and tightness. There is no fluid residue any where. Not around the slave master or any fitting. I have also checked the intermediate plate adjustment - lookls good. This really baffels me. Does anyone have any idea what could be causing this.

docmirror

Hate to be an old school hack, but has the system been bled the two-person, PITA method? When you say power bleed, I'm thinking you draw the fluid through the system from the slave. Since this results in an area of low pressure in the system, a chance for air entrainment is possible.

So, old school method.

Fill master res.
Pump clutch a few times, hold to floor.
Release bleed valve on slave fluid/air comes out. Close bleed valve.
Pump clutch, hold to floor.
Release bleed valve on slave fluid/air comes out. Close bleed valve.
Repeat until fluid shows NO bubbles. I use a clear, and then ATE super blue fluid. When the blue fluid shows up, I know the old fluid hs been purged completely.

hupp

Doc,

I've used the old school method, pressure bleed method and vacuum bleed method - I usually run one of the big brake fluid bottles through the system before complete. Each of these methods normally results in a semi-firm clutch pedal. I normally have to push the slave rod all the way in a few times before the pedal becomes firm. OR burp the master. Bottom line is that when I'm finished for the day the pedal is firm and the clutch operates properly. After sitting a week - soft clutch pedal.

MikeN

The "push the slave rod in" method has always worked for me better than anything else. Problem is you still have air getting in the system from some where, and my only advice is to check and recheck every bit of the system looking for any slight fluid leaks or any other place air could be getting in. You could have gotten a bad master or slave........not unheard of.

WallyP

I think that the problem is more likely to be the master cylinder sucking air in as the pedal goes up, releasing pressure. It seems less likely that air would be pulled in as the pressure plate pushes the slave in under pressure.

hupp

Thank you for your replies. I've checked all of the fittings in the system and everything is tight and dry. There is no evidence of leaks around the master or slave.

Wally P,

I've pondered that the master could be sucking in air, but if all fittings are tight where could the air get in (can this be an internal seal issue)? Wouldn't this also rear its ugly head immediatly. I can typically drive the shark around for hours after bleeding with no issue.

WallyP

My guess - emphasis here, "guess" - is that the seals in the master are allowing a tiny bit of air to be sucked in every time that the pedal is released. Eventually, this air builds up until there is enough to interfere with proper operation.

hupp

The dreaded clutch master replacement.

Wally P,

As much as I hate to think your guess is right, all the signs are starting to point to clutch master.

Based on what I've read, there should be two seals associated with the master piston. I've burped my master but when doing so I only observed one seal (o-ring) on the piston. I've looked for a cross section drawing of the master in the WSM, but came up short. Any good pictures out there of the clutch master.

Rez

Might as well replace the master cylinder too. Brakes and clutch will be rock hard.

Garth S

Should this be the chosen route, the "easy" way is to eviscerate the MC from within the car, leaving the cylinder in place: if the cyl. bore is clean, replace the piston/seal assembly. This may diminish the work for the "dreaded replacement" of the cylinder. The tougher part may be either getting the correct pistoin unit - or the whole assembly, and pulling the piston for the swap.
On the other hand, maybe the MC comes out easily ....

Rez - tell me that the races fell out easily ...

hupp

Rez,

The brake master is new. Brakes feel good.

Garth,

If I by a new clutch master, I will bite the bullet and replace the whole thing. The current clutch master is only about 6 months old. I guess some unwanted grit found its way into the bore - or something like that. This is just my luck. My old master was leaking into the cabin, but operated fine. I removed my engine 6 months ago and used this oppurtunity to replace the master. This master is giving me fits but does not leak fluid into the cabin. Now it looks like I'll get my chance to do it while the engine is in.

Rez

Tomorrow's project. I'll let you know.

Hupp. In that case may want to rebuild the clutch slave. Napa sells a rebuild kit for $25. Mine was pretty toasted, but works like a champ after the rebuild.