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I'm lazy, just tell me what's wrong

2K views 28 replies 9 participants last post by  SpecialTool 
#1 ·
OK here's the drill. Clutch has pressure, then two or three pumps later clutch has no pressure. Wait five seconds, clutch has pressure again, two or three pumps later it's gone again. Etcetera, etcetera.

What's gone wrong? Master? Slave? Flexible link? Or (fat chance!) will a bleed fix it?
 
#3 ·
Does the clutch engage if you keep the pedal depressed?

Alex said:
To check which end of the clutch has failed get someone to depress the clutch pedal then clamp the flexible clutch pipe (the one that leaves the slave). If the clutch stays down its the master, if it returns its the slave.
http://www.saabcentral.com/forums/showpost.php?p=8825&postcount=25
http://www.saabcentral.com/forums/showthread.php?t=49918

Any fluid leakage?

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#5 ·
Thanks for the input, SAAB friends. There's no fluid loss; my bet is it's the master. Will do more investigating on the weekend and try Alex's clever test.

Did I mention that when I went to pop the bonnet after making it home yesterday, the latch mechanism decided to stop working? One of those days...
 
#6 ·
Thought I would bleed the system first. Hooked up the trusty inner tube, loosened the bleed screw, pumped up the tube ... nothing. Took the bleed screw out ... no fluid escaping, under pressure or not. Why? Can a failed master, or slave, prevent fluid from flowing to he bleed screw?

( Decided to change the front brake pads while the car was laid up. Darn it, left CV boot was torn, so whipped out the axle. This old Aero is turning into a project car!)
 
#7 ·
I'm lazy, just tell me what's wrong..........

Global Financial Crisis
Global warming
Ongoing conflicts in troubled parts of the world
Fire
Floods
People losing jobs and-.......

Oh sorry,............ the CAR......?

 
#10 ·
THE ANORAK said:
is the flexi rubber in the clutch line balloning when pressurising?
No, the flexible line feels firm and looks sound.

I went ahead and pulled the master cylinder since it's an easy job. Will overhaul that and see if it works but I suspect I'll soon be tackling my first slave repair.
 
#11 ·
Its the master - these leak internally; if you were losing BF(brake fluid), then in all likelihood, it would be the slave..

Clutch hydraulics are the same as the brakes, but brakes very seldom leak BF..KOW:cheesy: ..knock on wood...
 
#12 ·
Not much time to tinker today but I did take the master cylinder apart. Seals looked OK (will replace them anyway) but everything was coated with a gunky brown ooze so will give it a good clean.

I mentioned earlier that I couldn't get fluid to come out the bleed hole when trying to do a pressure bleed. Maybe the clutch line is also gunked up with bad old fluid? Tomorrow I will use a syringe to try to pump some clean fluid through the lines and out the bleed screw. Maybe I should start with a solvent -- will brake cleaner do any harm?
 
#13 ·
SpecialTool said:
I mentioned earlier that I couldn't get fluid to come out the bleed hole when trying to do a pressure bleed.
Have you removed the bleed nipple completely? One of my rear calipers wouldn't bleed through - I had to remove the nipple, and clear it out. The old stuff looked more like the contents of a heavy smoker's lungs...

Maybe the clutch line is also gunked up with bad old fluid?
Very likely.

Tomorrow I will use a syringe to try to pump some clean fluid through the lines and out the bleed screw. Maybe I should start with a solvent -- will brake cleaner do any harm?
The name isn't a coincidence... <grin>
 
#15 ·
SpecialTool said:
Yeah, took the bleed screw right out and poked around a little but no flow.
Try standing on the pedal whilst the nipple's out... Bit of hydraulic pressure should free any gunk up.

I'm presuming you've slackened off the various unions in the line, one by one, from master to slave, and checked that you've got fluid coming to each?
 
#17 ·
Darn, not enough tinkering time lately, what with work and kids.

Just time today to rig up a little clutch system back flushing kit, consisting of a big syringe hooked up to the bleed screw via clear PVC. Pumped clean brake fluid back through the system and out the metal line where it joins the master cylinder (which my loyal readers will know has been removed for a rebuild).

The fluid first came out black and nasty, then gradually, over five or six syringes full, ran nice and clean. You bewdy!

Now to get myself a master rebuild kit, put it back together and see if I've got a working clutch again.
 
#19 ·
AUSSIE900 said:
Special .. Good stuff re fluid ..

Put a kit thru both ... whilst doing is good ..

Be horrid to button it all up and then have to do slave .. for the sake of a few dollar seal kit ..
You're right Les, I was hoping to get away with a master cylinder rebuild -- done it before so in my comfort zone -- but still no pressure so I'll tackle the slave (next weekend! Bloody kids will take up the rest of this one).

Aah well, it will be a good learning experience -- one of the few jobs I haven't yet had to do on a 900.
 
#21 ·
Originally Posted by Alex
To check which end of the clutch has failed get someone to depress the clutch pedal then clamp the flexible clutch pipe (the one that leaves the slave). If the clutch stays down its the master, if it returns its the slave.
Bought myself a proper brake line clamp after work today and tried this trick -- clutch went back up again, confirming it's the slave. Not too worried about the "wasted" master rebuild though -- it was quick and easy and probably a good idea anyway.

I've also made myself a spacer tool out of some 2.5 - 3mm wire. Still not sure which method to use to get it in there though -- the 30mm bolts against the flywheel or pumping grease into the slave. Plenty of time to think about it as I'll probably not have time to tackle it this weekend.
 
#22 ·
Found enough time today to get my home-made spacer tool in the clutch fingers using the bolt-against-the-flywheel method (tried the grease gun method but couldn't get a good enough seal against the bleeder screw).

Looks OK but still not sure if the spacer is doing the job it's supposed to. The release bearing spins freely -- is that a good sign?

Also, do I now need to remove the bolts and nuts used to compress the clutch fingers before I proceed with removing the slave?
 
#23 ·
More than a month after losing the clutch, I finally have it all fixed!

Probably only about four or five hours work all up ..such are the joys of a large and demanding family!

Anyhoo, rebuilt the slave and put it all back together with no great drama. Put the three bolts back in the flywheel, just enough to fit the nuts in so the slave wouldn't have to overextend to get the spacer out. Got a little helper to press the clutch pedal, the slave started moving then ... oh sheeit, lost pressure!

Turns out the flexible link was now the weakest link and had sprung a leak. Fortunately, this was a problem I had dealt with previously -- went to a hydraulics supplier and picked up some 6mm nylon tube and a couple of pressure couplings, all for under $10. Cut the rigid metal line either side of the broken hose and installed the new flexible line.

The interior of the old flexible hose, by the way, was an absolute mess -- I wonder if all the crud it had released into the system was the cause of the original problem?

The ol' bolt trick worked a treat -- and my indy was very impressed when he asked me how I intended to get the slave out without the special tool. (God bless the internet -- what would I have done ten years ago?)

Only small issue with the bolt trick was I chose 50mm bolts, which were a bit too long and rubbed the housing a tad. 40-45mm would be ideal.
 
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