Lotus Elan

Clutch pushrod

PostPost by: Zlinster » Tue May 16, 2023 8:43 am

I'm just rebuilding a clutch master cylinder for my S4.

I've removed the one on the car. It was full of gunge and crud. I guess that's why I was having slight problems changing gear. Fluid was weeping from the push rod boot in the footwell.

I have several old brake master cylinders and one clutch master cylinder in the box of bits that came with the car. I removed the push rod from a clutch and a brake M cyl looking for a good condition pushrod.

Thing is, as shown in the picture, all the pushrods are a little shorter than the dimensions in the BB bible.

It's this a problem? If it is then what shall I do?

At least I found one pushrod that looks nearly new.
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PostPost by: 2cams70 » Tue May 16, 2023 11:05 am

The pushrod is usually the last thing that needs replacing in a brake master cylinder. Why are you comparing against what is in a book rather than what came out of the car?
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PostPost by: Zlinster » Tue May 16, 2023 11:40 am

Because I don't think the pushrod was original by any means.

I have just looked in the footwell and notice that there are witness marks where the clutch lever has been pushed to the carpet.

I wonder whether an extra 5 mm or so of length is required.
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PostPost by: 2cams70 » Tue May 16, 2023 12:45 pm

Zlinster wrote:I have just looked in the footwell and notice that there are witness marks where the clutch lever has been pushed to the carpet.


The clutch pedal touches the floor - nothing unusual about that. It can have a whole lot worse consequences if you over stroke the clutch by having a rod too long rather than too short.
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PostPost by: Andy8421 » Tue May 16, 2023 2:55 pm

2cams70 wrote:
Zlinster wrote:I have just looked in the footwell and notice that there are witness marks where the clutch lever has been pushed to the carpet.


The clutch pedal touches the floor - nothing unusual about that. It can have a whole lot worse consequences if you over stroke the clutch by having a rod too long rather than too short.

Very true. If the rod is too long, the pedal doesn't allow the valve at the end of the master cyl to release at the end of the pedal stroke, with all sorts of problems. This has been the subject of many threads.

If its too short, the pedal hits the floor before the clutch fully releases.

If it worked before, I wouldn't over think it, and would stick with the same length.
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PostPost by: Zlinster » Tue May 16, 2023 3:32 pm

The thing is, and this is why I'm posting, I only bought the car in November, and until a couple of weeks ago I was going through the electrics, steering, etc..(a hundred and one etceteras).

Since driving it I realised the gear change was nothing similar to the gear change lovlieness that I've read about. Hence discovering the leaking master cylinder.

So it may be possible that I have never been getting the full clutch disengagement that is needed. Which led me to asking whether a pushrod that's 5 mm shorter than BB recommends may be critical.

I could use another of the same length pushrods that I've got (the one I removed has elliptical clevis pin holes) and see whether it is alright.

What do you guys recommend, please?
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PostPost by: gjz30075 » Tue May 16, 2023 4:09 pm

If you're a welder, or have access to someone who does, you can have washers with the same i.d.
as the clevis pin, welded to the pushrod fork, on the outside edge.
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PostPost by: Zlinster » Tue May 16, 2023 5:35 pm

A great hack! Thank you. Fortunately I've plenty of pushrods for the time being.
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