Need help diagnosing a clutch problem - Alfa Romeo Bulletin Board & Forums
 
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post #1 of 7 (permalink) Old 07-29-2016, 12:56 PM Thread Starter
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Need help diagnosing a clutch problem

My 1985 Graduate has started clashing gears when I try to shift into first or reverse and I could use some advise on what to try next.

It only happens occasionally, and only when the car is warmed up. When it happens, pumping the clutch pedal doesn't help. Touching another gear before shifting into first or rev usually works, but the other day I couldn't get it into rev without a big crunch no matter what I tried. I climbed under the car and had my wife work the pedal and the slave cylinder moved the fork ok, but like I said, the problem doesn't happen every time.

On the theory that you start with the cheapest and easiest I replaced the transmission fluid with Redline. No joy. And I bought the stainless steel clutch hose from Centerline but haven't installed it yet. Before I open up the hydraulic line to replace the hose, is there any way to know if the master or slave cylinders are failing?

Thanks for any advise!

Gene

85 Alfa Graduate
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post #2 of 7 (permalink) Old 07-29-2016, 01:35 PM
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Could be either, or both cylinders, could be some air in the system. Is the slave cylinder wet, or is the fluid level down in the reservoir? If, so replace the slave. If it's dry, and no fluid loss, there may just be air in the system, and when you replace the hose you'll have to bleed it anyway. You might also see a little fluid loss at the pedal side of the master cylinder, in which case, that would need replacing.

Finally, there's also the possibility of a failing clutch pedal pivot. Does the pedal appear lower than the brake pedal? If you reach down and grab the pedal, can you pull it up? If yes, then the pivot needs replacing.

Dean - '87 & '92 Spider Veloce's
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post #3 of 7 (permalink) Old 07-29-2016, 01:45 PM
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I'd install the clutch hose, bleed the system and see how it goes. Could be your hose is soft.

When you say the clutch fork moves ok, is it within the 10-11mm specs, like here in post #2?
http://www.alfabb.com/bb/forums/gear...-question.html

if travel is less, is the clutch pedal perhaps hanging lower than the brake? That could be a sign of a failing clutch pivot arm.

To see if the slave is leaking, peel back the rubber boot.....if it is filled with fluid, then it is!

My master was behaving ok, but I syphoned the fluid out of the reservoir (I wanted to wipe out the reservoir and clean it), then filled it with fresh Dot4 fluid, then pressed the clutch a couple of times, I noticed dirty black fluid come out the master into the reservoir.......that made me refurb the master.....it is usually a sign the seals are starting to disintegrate.

Dom - Alfa Spider 1990 S4 - formerly: Alfa 101 Sprint, 2600 Sprint, Montreal - family classics: Jensen Interceptor II, '58 Hooper RR Silver Cloud I, Shadow II, '60 Corvette.
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post #4 of 7 (permalink) Old 07-29-2016, 01:49 PM Thread Starter
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Thanks for the reply. The fluid level is down. I will check tonight to see if I can tell where it's leaking. The pedal height is fine and I did take a look at the pivot arm and it seem to be ok.

85 Alfa Graduate
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post #5 of 7 (permalink) Old 07-31-2016, 07:10 PM
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Quote:
Originally Posted by gdpedersen View Post
Thanks for the reply. The fluid level is down. I will check tonight to see if I can tell where it's leaking. The pedal height is fine and I did take a look at the pivot arm and it seem to be ok.
This is one of those jobs where it's easier to change everything at the same time.... Just because it's a pita to go through everything three times. Have you looks at the pedal pivot pin to make sure the weld has not given up its ghost?

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post #6 of 7 (permalink) Old 07-31-2016, 07:20 PM
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I would not replace a cylinder it is working OK. A new aftermarket part is often inferior to a used OEM part.

Ed Prytherch
79 Spider
85 GTV6 3L
76 Suzuki GT500
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A little government and a little luck are necessary in life, but only a fool trusts either of them. - P.J. O'Rourke
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post #7 of 7 (permalink) Old 08-01-2016, 05:56 AM
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I would not replace a cylinder it is working OK. A new aftermarket part is often inferior to a used OEM part.
Id argue that a 31 year old clutch cylinder is not better than an aftermarket component.. But I don't know the history of this particular cylinder. Maybe it's not OEM anymore... I'm more of a "look at the system and start from an equal baseline", but part of this is impatience I think. I really like driving the car and if I can avoid three separate troubleshooting events and bleeds I'll do it

1976 Alfa spider, with a 1978 2.0L engine and an 1985 rear clip.
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