Lotus Elan

Vague clutch

PostPost by: Robbie693 » Mon Apr 20, 2009 11:14 am

Another question..

Ever since I replaced the Master and slave cylinders on my Plus 2 last year the clutch has been rather vague with a fairly high bite position. I bled it a few times after installation but it made no difference so I hoped any remaining air would come out through the resovoir with a bit of use - but it's still the same after 12 months.

The bleed nipple and the pipe union are at the same height (i.e. horizontal) and I can't rotate the cylinder because the engine/gearbox shield is in the way.

I tried adjusting the pushrod and this worked for a few miles but then the freeplay disappeared.

Does this sound like an air problem still?

The clutch was fine before I replaced the cylinders by the way.

Robbie
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PostPost by: oldelanman » Mon Apr 20, 2009 1:12 pm

Hi Robbie,
That does not sound like air in the system to me. Air would cause long pedal travel with release/engagement near the floor and in extreme cases, no release at all. On the other hand a worn clutch and/or no operating clearance will lead to engagement/release near the top of the pedal travel and eventual slipping under load. Could it be that the vagueness you describe is the clutch partially slipping ? If this is the case it might explain why the clearance disappeared shortly after adjustment as the wear rate will accelerate dramatically once it does start to slip.

Another possible cause of vagueness could be the seals sticking in master or slave cylinders as this could cause slow clutch engagement and consequent slipping when the pedal is released.

Probably not what you wanted to hear but I hope this helps.

Good luck.
Roger
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PostPost by: paddy » Mon Apr 20, 2009 3:08 pm

Missing/weak return spring?

I would try and find out whether or not the release arm is retracting fully when the clutch is released. If it is possible to further retract the arm by hand after fully depressing and releasing the clutch pedal, there's a problem somewhere, either:
- pedal not full retracting, so master cylinder remains closed preventing the slave from retracting;
- return spring missing or weak;
- new slave cylinder unusually stiff.

I've no idea what the "vagueness" might be.

Paddy
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PostPost by: Frank Howard » Mon Apr 20, 2009 4:45 pm

Robbie693 wrote:The bleed nipple and the pipe union are at the same height (i.e. horizontal) and I can't rotate the cylinder because the engine/gearbox shield is in the way.

Robbie,

This could be your problem. The bleed nipple should be at 12:00 while the pipe union is at 6:00 so that when you bleed the slave, any air will be trapped at the top of the cylinder and should then go out the bleed screw. If you have an engine/gearbox shield, it's likely that it is not a factory part and was fabricated by a PO. You'll have to alter the shield so that you can rotate the slave cylinder to the correct position before you bleed it. Let us know if this resolves your issue.
Frank Howard
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PostPost by: Robbie693 » Wed Apr 22, 2009 9:29 am

Thanks all,

The clutch isn't slipping and was fine before I changed the hydraulics so I'm hoping it isn't the mechanical side of things.

I'll try another bleed, maybe with the slave out of the gearbox so I can rotate it a bit and also check the return travel and spring.

By vagueness, I mean that the engagement period seems a bit long, if that makes more sense.

Cheers

Robbie
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