AW11 Clutch Bleeding Question: Grassroots Motorsports forum: Grassroots Motorsports Magazine

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June 8, 2009 9:46 p.m. pinchvalve UltraDork

So the wife was enjoying Senior Dos over the weekend, when the car suddenly would not go into gear after being parked. After a tow home, my guess is that it is low on clutch fluid. No idea where a leak could be, I don't see anything under the master or slave cylinder at all. So I decided to bleed the system. I was able to get some pressure back and the car will shift OK, but all of the friction occurs in the first 1 inch off the floor. Way to abrupt, still not right.

When I am bleeding it, I see no bubbles coming from the line at all. Seems like solid fluid, no foam, no pockets, no bubbles. So am I missing something?
June 8, 2009 10:11 p.m. NONACK New Reader

Bleeding the clutch on my SW20 took forever, so I wouldn't be surprised if there's still some air hiding in there. If you really bled it a lot... look for leaks in the hard line? Mine sprung a leak right where the line bends up from under the floor towards the slave cylinder.
June 8, 2009 10:13 p.m. highdensity New Reader

same sort of thing happened to me. check the pushrod behind the pedal for wetness--you could be leaking fluid inside the cabin.
June 8, 2009 11:54 p.m. fiat22turbo SuperDork

On the Fiat X-1.9's they found that cracking the joints and bleeding the entire system from top to bottom was sometimes the only way to get the air out completely.

Might be worth a shot to build a pressure bleeder system and briefly crack the fittings bit by bit until you get all the way to the end.

http://www.bmw-m.net/TechProc/bleeder.htm

http://faculty.ccp.edu/faculty/dreed/campingart/jettatech/bleeder/index.htm

Good luck!
June 9, 2009 7:41 a.m. Jensenman MegaDork

It sounds to me like it's sucking in air at the master cylinder. You have to stand on your head and look under the dash, but generally you'll see fluid running down the firewall where the master cylinder pushrod goes in. If there's a boot on the M/C, pull it back with a screwdriver and usually fluid will pour out.

What hapens: the 'cup' on the piston gets worn. When the pedal is pushed, the cup reacts to the hydraulic pressure and is pushed out against the cylinder bore. When the pedal is released, the cup no longer has this pressure to make it seal and this allows air to be sucked in past the cup. You can bleed the thing till doomsday and never get it to work properly.
June 9, 2009 8:11 a.m. Dr. Hess PowerDork

Look under the carpet, you'll find all your clutch fluid. Common problem. Yes, you have to replace the master cylinder every 100K miles or 10 years, which ever comes first.
June 9, 2009 10:36 a.m. pinchvalve UltraDork

So 20 years and 200,000 miles, I am a bit past due eh? OK, off to Rock Auto for every part in the system just in case. Sometimes you just gotta say, "when in Rome".
June 9, 2009 10:42 a.m. Dr. Hess PowerDork

Yeah, you were past due. I'd get at least a slave cylinder kit and a new MC.
June 9, 2009 10:45 a.m. pinchvalve UltraDork

Dr. Hess wrote:

Look under the carpet, you'll find all your clutch fluid. Common problem. Yes, you have to replace the master cylinder every 100K miles or 10 years, which ever comes first.

OK, I pulled up the carpet. Yep, there's my clutch fluid! Thanks for the tip. The slave was replaced just before I bought the car and looks to be in excellent shape, so I am replacing the front cylinder completely. Rock Auto doesn't carry it, but 1st Toyota does.