Lotus Elan

clutch adjustment

PostPost by: tdafforn » Wed Jan 09, 2008 2:38 pm

Dear all,
Been having some fun with the clutch hydraulics.
I removed the slave and swapped the old rigid lines for a braided hose from Matty's during the engine rebuild.
Then found I could only get the clutch disengaged with two pumps of the pedal.
then spent 2 days bleeding the clutch multiple ways (bleed nipple uppermost of course.)
The noticed somehting.
The manual says to adjust the actuator rod until there is 2mm gap between it and the lever. Now, I have fitted a new rubber cover for the lever where it enters the bell housing. The new cover pushes the lever forwards quite a long way meaning that when I adjust the rod to tolerance it actually has to push the rod a long way until the thrust bearing even touches the cover plate.
I reasoned that this is why it takes 2 pushes of the pedal, the first pushes the piston in the slave forwards to take up the slack and the second disengages the clutch.
To test this I have adjusted it with my hand pushing the lever backwards so that the bearing is touching the cover plate and then adjust the rod to 2mm from the lever.
Result, the clutch feels right and works first push..
Anyone have any thoughts? is this correct?
Tim
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PostPost by: john.p.clegg » Wed Jan 09, 2008 4:12 pm

Tim

Yes,you're right,the 2mm play should be when the arm is engaged with the release bearing...

John :wink:
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PostPost by: tdafforn » Wed Jan 09, 2008 4:37 pm

excellent, although it does mean that I
1) spent 4 days under the car in sub zero temperatures with a cold,
2) bought a slave and master cylinder needlessly
3) learn't new ways to twist your arms when undoing the pedal box!
4) annoyed the MOT tester with a car that passed despite a dodgy clutch
5) got air in the brake circuit due to having to remove the master cylinder with the pedal box



All for now't!
Tim
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PostPost by: pamitchell » Wed Jan 09, 2008 5:15 pm

Tim;

Been there, done that too!
I installed a remote bleeder for the slave by running a flex brake line from the slave and tied it off to the heater valve on top. Installed a Speed Bleeder valve on this line so it is now a 1 man job working from the top of the engine bay.
Your back and arms will thank you.
Phil
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PostPost by: john.p.clegg » Wed Jan 09, 2008 5:30 pm

Phil
Like that idea,remove the bleed nipple (uppermost position) and replace with a little hydraulic pipe (whatever takes your fancy) with a check-valve at the end...

Nice one!

John :wink:
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PostPost by: 264889socal » Wed Jan 09, 2008 5:41 pm

Tim,

I just went through the same nose bleed as you. My trials started with failing to read Brian's book completely. I failed to bleed the clutch prior to installing the headers. Lucky for me, I had a flexible line between the master cylinder and the slave cylinder. That helped. One thing I found was removing the rubber cover on the bell housing prior to trying to adjust the free play. Even then, I could not get enough pedal travel to completely disengage the clutch. I used more than a pint of fluid in the bleeding operation without total sucess. I finally got enough travel to get the car in gear with one depression of the pedal. But the pedal still engaged just above full travel. In frustration, I decided I really needed a nice drive in the country and to hell with the clutch. During my drive, by the continous depression of the pedal, what air remaining in the system found its way out through the master cylinder. Wasn't much as the fluid level did not drop noticably. Now everything is working as normal. I know the next time I have to remove the engnie and transmission, I will remove the circlip from the slave cylinder and withdraw the cylinder from the bell housing and make a plug to retain the piston in the slave cylinder. Then hang the clyinder up and out of the way. Upon reinstallation, no bleeding should be required.

Rob
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PostPost by: oldokie » Wed Jan 09, 2008 5:58 pm

I have always been able to get away with just "cracking" the bleeder abit and letting it drip very slowly for 10 or 20 minutes. Tighten it up and everything is fine.
Gene
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PostPost by: peterako » Wed Jan 09, 2008 6:12 pm

Hi Tim,

I've been through that heartache too! (Replaced cyliners, pipe etc!)

But, now it's set up with the REAL 2mm clearance it's a dream.

The rest was a nightmare!

Now enjoy the damn thing!!

Peter '73 +2S 130/5
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PostPost by: RotoFlexible » Wed Jan 09, 2008 6:46 pm

The only place I can see that air can accumulate is the high point of the hose line where it leaves the MC. It's a long way down from there to the slave so it would take two or three vigorous pumps, quickly repeated, to get all the air down the hose and out the bleeder. I think that if you bled the slave before installing it, by holding it above the engine bay (with something to keep the piston from shooting out) you would get all the air out more easily.

I've also experienced the welcome relief of the last of the air just sort of disappearing by itself when I drive the car.
Andrew Bodge
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