On Friday,my 87 740 Turbo Wagon's Clutch Slave gave up the ghost.
I was unhappy since this is my first 'breakdown' since new !
No big deal I ordered a new slave and installed it and was trying to bbleed the lines.

I had a hard pedal in 3 to 4 pumps and i thought I was home free --- Bled the line and went thru the same motions. But this time the pedal got real hard and was only halfway down the floor. I pushed a little more and apperently ripped the seal on the piston inside the new slave.

So I said no problem, let me temporarily use the old piston with the old seal.

Went thru the same bleeding process and same results.

Now it was tome to look at the fork which appears file and the travel is about an inch on it -- so it is not that it is bent and the slave piston popped out too far.

It is almost that when I stay off the clutch that the pressure is not going back -- almost feels like the pressure builds up on every push of the clutch pedal.

Do I have a bad Clutch Master Cylinder ? It is original !
Can I buy the slave piston seal on its own at the dealership ?

Any help is appreciated !


Thanks

I suspect your flex line is swollen shut to form a one way valve. I have seen this 3 times on brakes on older cars. The lines swell internally so the fluid will pass thru - more pressure on the push stroke, and not return- less pressure from the clutch. My thought is your piston is not returning and the next pedal stroke pushes it too far.

Mike in tacoma

This should be a pretty simple system. Maybe a piece inside the flexable hose has come off making a "one way valve" so that the pressure in the slave cylinder can't be released ?

i have had similar type weird experiences when bleeding my clutch ..specially the getting harder with each pump, i think that turned out to be air...also i somehow had to make my own slave push rod (a bolt with the head cut-off) the volvo one was too short...but now i am having to cut it shorter (to stop clutch slip)...ur not alone...keep trying u will figure it out..daryl

I too had to make a longer push rod. I think it was because I used a slave cylinder from a 90 (with stepped flywheel) when I converted my 88 (with flat flywheel) to a stick. At least that's the only reason I could figure out why the original was too short.

I am familiar with the internally swollen brake hoses. This was a common problem on 140s

CarQuest was able to get rebuild kits for both clutch cylinders. The one for the master was correct, the one for the slave had the wrong internal seal--it was the correct diameter but wasn't wide enough to fill the slot in the piston. I ended up reusing the old one, which seems to work OK. The outer boot was the right one, and was the main thing I needed, as the old one was badly cracked.

Sounds like a flipped or rigid seal in the master cylinder. I was able to find a rebuild kit for mine but these may no longer be available. Be sure to check the grommet and line between the brake reservoir and the master cylinder. It took me forever to find a cracked grommet that had started the whole replacement cycle.