Lotus Elan

Clutch Adjustment

PostPost by: robb4100 » Fri Sep 03, 2004 1:33 pm

Hi Everyone,

My 65 Elan needs to have the clutch cable adjusted. It currently engages near the bottom of the pedal travel. I would like to bring it up a little. Can someone give me some advice on how to do this? Are there critical errors that I need to avoid.

Thanks

Robb
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PostPost by: type26owner » Fri Sep 03, 2004 2:10 pm

Hey Robb,
The clevis pivot on the brakes and the clutch pedal assemblies are rapid wear items even if they are lubed on a regular basis. When they wear out (~25k miles) they cause lots of the available actuation travel to be greatly reduced. Probably this is the cause of most peoples complaints about the clutch and brake not feeling right or disengaging at the end of travel. It's a pain to fix but really worthwhile. I make my own replacements out of bearing bronze which about doubles the lifetime. Check it out carefully.

The female clevis is on the master cylinder side. So what happens is the male lever and pin wear out the pin holes in the clevis into elongated slots about 1/4" long. This process stops when the lever's profile eventually rubs up against the end of the lock nut holding the clevis to it's shaft which extends into the hydraulic cylinder. About half the pedal travel does not do anything cause of this looseness from then on. BTW this is not particularly dangerous but it is rather annoying. The brake pedal should only depress in only about 1/2" before going fully hard if there is no clevis slop. The hydraulic type clutch should fully disengage within the first 2" of pedal travel. If you have a cable actuated clutch mechanism most likely it will still have a similiar clevis arrangement.

My brother's Caterham Super7 has a 5k mile endurance between failures for the clevises. Good thing there is an access plate which makes it very easy to swap the new in for the old ones. Because it's not too painful he won't correct the problem. :huh:
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-Keith
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PostPost by: 1964 S1 » Fri Sep 03, 2004 11:33 pm

Your Elan has a cable? I"m thinking it's hydralic and you need to do one of the following, in easiest first order:
1. Fill the resevoir and then pump the pedal. (It's the inside resevoir on LHD cars)
2. Bleed the Clutch
3 Replace the slave cylinder or master cylinder
4. Replace the clutch

I also recommend buying a shop manual, whether you work on your own car or not, you can at least "stay on the same page" as your mechanic.
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PostPost by: robb4100 » Sat Sep 04, 2004 2:41 am

My screw-up,

Yes it is a hydrolic system. The clevis pin/pushrod assembly at the pedal is fine. and when I checked out the slave cylinder push rod the nut had been adjusted almost to the very end (closest to the fork). The reservoir is full so it sounds like the best thing to do is bleed the system and hope that does the trick. I'll probably leave the last two items to my mechanic if it needs to be done.

If anyone has other ideas let me know.

Thanks for the help

robb
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PostPost by: Frank Howard » Sun Sep 05, 2004 5:56 pm

Robb,

Before you bleed the system, make sure it is hooked up correctly. There are two holes on the rear of the clutch slave cylinder. They are both threaded the same. Make sure the line goes into the bottom hole and the bleeder screw goes into the top hole. If they are reversed, you will never be able to rid the slave of an air bubble.

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PostPost by: khamai » Mon Sep 06, 2004 2:53 am

The Clutch master is a 5/8" ID. It pushes just enough volume. As things wear - clutch, clevis, etc it requires more volume & less volume is pushed out of the Master hence not enough clutch arm movement. Thus the clutch will barely disengage with the pedal completely depressed.

If you haven't already done so DUMP the red hose!!! Use a braided line.

One fix is to go to a 0.7" ID master. It will require a bit more pedal pressure and it will be more difficult to slip the clutch (engagement travel is shorter), but you'll find that the added volume will push the clutch arm a greater distance and fully disengage the clutch.
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PostPost by: Unibrain » Mon Sep 06, 2004 5:53 pm

After everything checks out and is found OK and you still want the point of disengagement higher you can switch to adjustable length push rods. I did this on the brake and clutch to take up more of the free play.

<a href='http://www.unibrain.org/motorsports/elan/gallery/brakes' target='_blank'>Adjustable Push rods</a>

Any of the specialist can supply the push rods.
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PostPost by: khamai » Tue Sep 07, 2004 1:36 am

Adjustable push rods work. Just be careful not to make them too long. If it pushes the pedal complete out it make not allow the piston in the master cylinder to fully retract and "refill" the system from the reservoir. Just a word of caution.

Also note an adjustable push rod may not force more fluid volume out of the master (thus no greater clutch arm movement). It will make your pedal higher.

I've tried most all of the above suggestions. My thought was that I needed more clutch arm movement to fully disengage the clutch as the bottom of the pedal stroke. That wasn't happening. I tried the adjustable/longer push rod, braided hose, bleeding, etc. Ultimately I ended up with the 0.700 Master.

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