Clutch prob­lems

Car Mechanics (UK) - - Help! -

I would like to ask your ad­vice re­gard­ing prob­lems I have with the clutch on my 1991 Saab 9000 2.3T man­ual with 220,000 miles. I de­cided to re­place the clutch pres­sure plate, fric­tion plate and re­lease bear­ing on the car, to­gether with the slave cylin­der. All parts were new Borg & Beck items bought on ebay. Af­ter many hours of work, I was pleased with the smooth oper­a­tion of the new clutch, with no slip­ping in fourth or fifth gears. The old fric­tion plate still had some fric­tion ma­te­rial re­main­ing, but one of the springs had be­come very loose.

The car was then left for about three weeks as it is only used as a sec­ond car. The next time it was used, I found the clutch pedal sank to the floor with very lit­tle pres­sure and I could not se­lect any gears. How­ever, all the clutch con­nec­tions were bone dry, with no signs of leaks, so I as­sumed that air had some­how en­tered the sys­tem. I bled the clutch again us­ing a Gun­son E-Z Bleed tool, but could not de­tect any air pock­ets/bub­bles, etc, from the clutch bleed tube. Af­ter­wards, the clutch pedal still sank to the floor with lit­tle pres­sure.

Think­ing it must be the mas­ter cylin­der that had failed, I changed it for a new Lock­heed unit and bled the sys­tem again. Ini­tially, this did seem to im­prove things, but by the time I had the car back on its wheels, the pedal was still not op­er­at­ing the clutch.

Have you any thoughts about what is go­ing on here? The only pos­si­bil­ity I can think of is that the mas­ter cylin­der had been stored for about 10 years, so could have de­graded. Could the new slave cylin­der be faulty? I thought slave cylin­ders could only fail due to ex­ter­nal leaks, which would be ob­vi­ous. There is ob­vi­ously still air in the sys­tem, de­spite re­peated bleed­ing. Ger­ald Reeves I am as­sum­ing that the clutch does not clear when it sinks to the floor, and that you don’t have an ex­cep­tion­ally light pedal. I say this be­cause I have of­ten been sur­prised at how light a new clutch can feel. When the slave cylin­der fails, it is nor­mally in­clined to draw air into the sys­tem. Fail­ure of new parts is quite rare, and pro­vid­ing the cylin­der had not been ly­ing around for years be­fore it was sold to you, its fail­ure is quite un­likely, al­beit not im­pos­si­ble.

How­ever, hav­ing been sit­ting for some years, the mas­ter cylin­der could have dried out and failed, al­though I would ex­pect this to re­sult in a de­tectable leak from the pushrod seal. If I re­call the sys­tem on your Saab cor­rectly, there is a me­tal pipe go­ing down to­wards the gear­box that has a flex­i­ble hose be­tween the pipe and the con­nec­tion to the slave cylin­der (part no 4903670). You should en­sure that this hose has not failed, as they do have a ten­dency to break down in­ter­nally, al­though if that were the case I would ex­pect at least a small sign of fluid around the pipe.

It may be pos­si­ble to iso­late the prob­lem by bleed­ing out the clutch again, then clamp­ing off the hose. If the pedal re­mains firm for some time, then the prob­lem does point to the slave cylin­der. How­ever, you must re­mem­ber that, with the hose clamped off, the pedal should not de­press as the fluid can­not travel along to the slave cylin­der. The only dan­ger with this method is that if the hose has be­come frag­ile, clamp­ing it may fin­ish it off!

The hy­draulic clutch feed pipe with a flex­i­ble end con­nected to the me­tal pipe.

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