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Discussion Starter · #1 ·
When I was moving the 9k around yesterday (first time it's run in a few months) I noticed that the clutch pedal has a lot of play (like nearly 1/3 of it's travel) before I feel any resistance from the master cylinder. I hadn't noticed it being like this previously but it could be a worn pedal mechanism (esp if it has the same clevis wear issues as a C900's clutch pedal mechanism) or a suspect master cylinder. Gear changes in/out of 1st and reverse were fine though I had to push the pedal down all the way.

Any ideas?

Craig.
 

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I'd rebuild the clutch master (seals, honing) as preventative maintenance and check out the clevis,,,Maybe a new larger pin and a re-drilled hole...its probably the same as a FIAT group system... Perhaps they use a bushing which could be replaced.
 

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The vehicle had been idle for an extended period, is it possible that the level of hydraulic fluid in the master cylinder dropped to a point were air has become entrained or that a cup seal has collapsed.

The seals in older hydraulic piston/cylinder assemblies (both slave and master) tend to lose their elasticity over time. They like to be exercised on a regular basis.

If the level in the master shows full, the leak might be internal, allowing the piston to advance without pumping any fluid.

Before anything else, I'd top off the reservoir and pump the hell out of the master. It might regain it's pumping effect as the seals get flexed.
 

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Worn clevis pin is a possibility but it wears oval causing a popping sensation as the pedal goes down.

Common cause of MC failure is the internal return spring fails causing the floating piston to fail to return all the way.

Unless pumping the pedal as suggested fixes this I suspect your MC needs replacing.

Is yours on the false bulkhead as for old style 9000 or above the pedal inside the cabin as for late models? The former are very prone to failure due to their upright situation.
 

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Discussion Starter · #5 ·
Good idea re checking the fluid and pumping to see if it recovers it's 'operational readiness' so to speak. I don't know which type of master it's got as I've not needed to look for it until now.

Next time I'm at the car I'll check it out and report back. Just about to head out the door to work (11 pm start, lifted up from 1 am start) once I finish my coffee.

Craig.
 

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New style is inside the cabin right above the clutch pedal. Older style is under the aquarium cover on the left side of the false bulkhead area. However, this is for LHD cars. I am not sure how the clutch hydraulics are adapted to RHD.

Either one uses the brake MC reservoir for fluid. The take off for the clutch is higher up on the reservoir so if the brake fluid gets low the air gets into the clutch line before you lose the brakes. BTW how is the fluid level in the brake MC? That just might be the problem.
 

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9000 hydraulic clutches are notoriously finnicky. I had one which was working fine lose all pressure while parked at an airport for 3 weeks. I had to drive home with no clutch, but after furious pumping it started to work right about when I got home. Then it worked fine for a year until the slave cylinder/throwout bearing catastrophically failed on the highway.

Yesterday, I just replaced my master cylinder _again_ after the crappy aftermarket one failed (push rod came off). I put a used Saab one in from my parts car.

I recommend bleeding it carefully with a pressure bleeder and see if it stays fixed. Almost every time I've taken out a Saab master cylinder (more often than I'd like) they are filled with icky goo. Now I bleed mine at least once a year. Takes about 10 minutes with a pressure bleeder...

Change your clutch hydraulic fluid often--replacing the slave cylinder is a big job...
 

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Discussion Starter · #8 ·
I had a good look at this today, and I can confirm it is the pedal mechanism. The pedal itself moves about 25 mm before any movement of the master cylinder's control shaft occurs, and the clevis is very worn (it moves about 10 mm or so).

So it looks like I need to renew the pedal mechanism parts or take it out and see if I can get some sort of a sleeve welded in for the pin to locate in. I am still going to get it bled though to flush out the old fluid when I get the time.

Craig.
 

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excessive

hi.out of interest, even though you say there's a lot of movement at the pedal itself, check the fluid if it appears dark/discoloured then when time comes to refurbish the MC, and posssibly the slave, replace the flexible hose on the MC to slave line.this hose over time and that time is now deteriorates and you will be replacing the slave very frequently believe me-been there with my '88. love that car.cheers.
 

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Discussion Starter · #10 ·
hi.out of interest, even though you say there's a lot of movement at the pedal itself, check the fluid if it appears dark/discoloured then when time comes to refurbish the MC, and posssibly the slave, replace the flexible hose on the MC to slave line.this hose over time and that time is now deteriorates and you will be replacing the slave very frequently believe me-been there with my '88. love that car.cheers.
Heading down to where the car is again today. The line to the master cylinder appears to have been replaced at some point as (unless it's an original config) the line is made from braided hose.

I might see if I can get the pedal out of the car but the last time I looked at it, the wear is in the pedal itself. I think the fairly thin (1.5 mm or thereabouts) steel the pedal is formed from has worn where the clevis pin goes through it. I have heard of repairs to this sort of problem on classic 900's involving fitting a piece of steel tube through the pedal and welding it into place so the pin has a large surface area to act on instead of two thin surfaces where it goes through the standard pedal fabrication.

Craig.
 

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I believe the braided hose is original material.

It is probably easier & cheaper to get a new clutch pedal from Pick n' Pull than to try to weld up the old one. But we have lots of pick n' pulls nearby...
 

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Discussion Starter · #12 · (Edited)
Using a larger clevis pin with slots re-formed to larger holes?

My Saab parts guy the other day suggested the best way he's come up with to deal with 'slotting' in clevis pin holes and clutch/brake master cyl forks is just to drill them out to fit a larger pin. 10 mm (close to 3/8") is the suggested size. I think the standard one is about 6 mm (1/4")?

Apparently it can be done without removing anything from the car using a right-angled drill and a shortened bit. I have neither of those items currently but could give me an excuse to get them.

This method wouldn't address the possible issue of excessive cluster master bore wear in a limited movement range due to the pedal play, but it seems worth trying.

Anybody actually done this (especially on a RHD 9k)? Can the fork section on the master cylinder shaft actually be unscrewed because that might allow fitting a different fork? I don't remember if the clutch MC in my car has a removable fork that the clevis pin goes through.

Craig.
 

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Discussion Starter · #13 ·
pic to show exactly what's going on

Decided to investigate this today. So I've taken out the pin and this picture shows that the majority of the wear is the clutch master cylinder clevis fork itself.



flickr page

The pedal actually appears to be a solid piece of metal and it's hole is not very worn but still does have a small amount of slotting.

The pin itself where the ends were located inside the holes (now slots) of the MC fork, is also worn.

The car is RHD and the clutch master cylinder as can be seen in the picture is directly behind the pedal. So that answers the question of how RHD 9k's are set up clutch-MC-wise. I don't actually know anything about the MC itself and have never really looked up from underneath to see the rest of it.

But it's clear the MC's fork has a lot of wear.

So while I don't have funds to get a new MC, I will get a bigger pin (3/8" is the size closest to 10 mm, and to make it a good fit I could drill out to 9.5 mm instead of 10 mm), get the pedal itself out to drill it's hole, and carefully work on the MC fork. Seems like it's worth a go.

That big ugly round thing behind the MC fork is the bottom end of the steering shaft going out to the rack.

I'm going to fully re-fluid the clutch when I fix up the pin business and brakes too since it's time both systems had a bleed (are they one and same system in a 9k btw?).

Craig.
 

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Discussion Starter · #14 · (Edited)
Getting clutch pedal out to start fitting bigger pin

Removing the clutch pedal is an interesting process. Almost no access (I don't want to remove the drivers seat yet!), the nut that's accessible from around the steering shaft is one of those self-locking types that's difficult to hold a spanner on. I will probably not re-use that and go for a nylock nut instead. It's a bog-standard 10 mm thread.

With that off, the long bolt comes out easily as does the spacer tube that braces the adjacent brake pedal bracket, then the pedal itself is free except for the 'clock spring' that gives the pedal-return action (and shows up the freeplay).

Ok well got the clock spring un-hooked and got the pedal out. I measured the length of the 'slot' on the clutch master cyl fork and it's 11 mm. The normal pin appears to be 8 mm.

All I could get from the auto parts places was an 'assortment' pack of clevis pins of various OD's, one is about 10.5 mm OD and that is what I'll use. It's too long so will need shortening to the same length as the existing one but that's simple. I will be using a split pin not the spring clip that's on the existing pin to secure it once I decide the best way to re-shape the 'slotted' original holes.

Here's the pedal showing the clevis hole and you can see it's enlarged on one side by an extra couple of mm:



flickr page

With careful filing and drilling, I've mostly re-centred and enlarged the hole in the pedal itself to 11 mm which allows a neat slip-fit for the 10.5 mm OD pin. No problem.

However, getting a way to enlarge the slots on both sides of the master cylinder fork is definitely not going to be possible with the MC installed, so I'm considering going 'whole hog' and jacking up the front of the car to access the master cylinder, disconnect it, and remove it, so the fork's slotting can be corrected properly out of the car. Of course that affords me the chance to bleed the clutch and brakes after that's done.

The master cylinder is directly behind the clutch pedal location (RHD car) and looks like it's secured from the engine side of the lower firewall? Before I commit to that rather than abort and save for a complete new MC, is there anything to watch out for when removing the MC for a RHD 1990 9k? How accessible is the other end of it?

If I replace it with a new one, EPC says 43 85 019 is the correct p/n, but it also shows up another p/n of 89 57 292. And good/bad brands for these?

Craig.
 

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Discussion Starter · #15 ·
How to successfully bleed the clutch system ???

Since doing this, I corrected the clevis pin holes in the pedal, and also took the MC out to do the same thing with the 'slotted' holes in the clevis fork.

All good there - now there is no pedal play.

But I can't get the clutch to bleed properly. I've pressure-bled it to get no air bubbles out, and pumped the pedal 50+ times, and I get resistance from about half-way down.

I've been told a solution is reverse-bleeding. ie. connecting a supply of brake fluid to the clutch slave cylinder bleeder nipple and pushing air back to the brake fluid reservoir. People who mentioned they've tried it said to get a big syringe, fill it with fluid, connect to slightly-cracked bleeder nipple, and push air back up.

Now does this actually work? How would you get a proper seal when the bleeder is cracked if a supply of slightly-pressurised brake fluid (via a big syringe) pushes fluid through from the slave cylinder? Once the bleeder is cracked, wouldn't any pressure just push fluid out through the thread where the very long machined bit of metal forming the bleeder nipple screws into the casing of the slave cylinder?

I will get a new master cylinder if I need to, but while I'm still unemployed I'm trying whatever methods I can to correct the clutch operation. The pedal play was a purely mechanical issue to solve.


Craig.
 

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SNIP--

I've been told a solution is reverse-bleeding. ie. connecting a supply of brake fluid to the clutch slave cylinder bleeder nipple and pushing air back to the brake fluid reservoir. People who mentioned they've tried it said to get a big syringe, fill it with fluid, connect to slightly-cracked bleeder nipple, and push air back up.

Now does this actually work? How would you get a proper seal when the bleeder is cracked if a supply of slightly-pressurised brake fluid (via a big syringe) pushes fluid through from the slave cylinder? Once the bleeder is cracked, wouldn't any pressure just push fluid out through the thread where the very long machined bit of metal forming the bleeder nipple screws into the casing of the slave cylinder?

I will get a new master cylinder if I need to, but while I'm still unemployed I'm trying whatever methods I can to correct the clutch operation. The pedal play was a purely mechanical issue to solve.


Craig.
Wrap a bit of teflon (plumbers) tape around the threads. That should maintain enough of a seal--you'll have more resistance across the threads then flowing up to the reservoir is the idea. The fluid will take the path of least resistance. Also, a little fluid coming out around the threads (of the bleeder valve) doesn't mean more fluid isn't going up to the reservoir. Be sure not to overfill the reservoir...

I've also read (but not tried) of running a hose from a rear brake bleeder to the slave bleeder and powering the abs pump for 30 sec or so to bleed the clutch system.

The syringe idea sounds easier...
 

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Yessss It Actually does work.
Really darned well when all is said and done. Despite all worries.
Do note that it takes a long time to pump in a 2 oz Syringe full of Fluid.
There is genuine system resistance
So be patient and keep at it.
 
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