Lotus Elan

Clutch Biting Point Very High

PostPost by: adigra » Wed Mar 19, 2014 9:31 pm

Hi all,

I picked my car up from Option 1 today (it looks fantastic!). They had the engine out during the restoration. I had a new clutch fitted last year and it was working great, and has only done 600 miles at most, but now the biting point is at the very top of the travel. It makes it quite awkward to drive smoothly. Otherwise it works as it should, no slip, just makes it tricky to use smoothly.

I'd really appreciate some suggestions as to what might be the cause of this.

Thank you!

Adi
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PostPost by: adigra » Wed Mar 19, 2014 9:35 pm

I should also add that no parts were changed at Option 1, just put back. The master cylinder and the slave cylinder are also fresh, about 2 years old.

I know that in the past there were suggestions made about shortening the actuating rod, but how would I do that, and more confusingly, why if it was fine before?
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PostPost by: robertverhey » Wed Mar 19, 2014 9:39 pm

Actuating rod that protrudes from slave cylinder is adjustable (well it is on mine anyway), you should be able to get the pedal to bite lower down I think?
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PostPost by: adigra » Wed Mar 19, 2014 9:48 pm

Thank you Robert! I'll have a look at it.

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PostPost by: gjz30075 » Thu Mar 20, 2014 11:30 am

Actuating rod adjustment could be too tight, ie, the throwout bearing is already riding the pressure plate and 'semi' actuating the clutch without your involvement.
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PostPost by: adigra » Thu Mar 20, 2014 11:45 am

Thank you. That seems to be the conclusion, as Frank from Option 1 says they probably set it too tight. I don't have the time to look at it until the weekend, but I feel happier now. After a very long day yesterday going to pick the car up I was feeling really frazzled.
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PostPost by: CBUEB1771 » Thu Mar 20, 2014 4:46 pm

Setting the clearance between the slave cylinder push rod adjusting nut and the clutch release arm according to the work shop manual has always worked well for me. The clearance should be 0.08" (2.0 mm) as shown in the drawing in the manual. First make sure that the clutch is bled completely and that the slave piston is not retracted into the slave cylinder bore too far. I find that in bleeding the clutch it is necessary to get the air out then stroke the clutch pedal a few times to make sure the clutch release arm is moving and then check for air in the hydraulics once again.
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PostPost by: mcclelland » Thu Mar 20, 2014 5:51 pm

Hi,
I think you need to check and then adjust the push rod in the clutch master cylinder. Sounds to me as this has been wrongly set up. Cant remember the setting, but its clearly shown in the manual. Hope this helps.
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PostPost by: CBUEB1771 » Thu Mar 20, 2014 9:21 pm

The master cylinder push rods have a fixed length whereas the slave cylinder push rod has adjustable length. One problem is that replacement master cylinders never come with the correct length push rod, I have always had to re-use the original master cylinder push rod.
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PostPost by: adigra » Thu Mar 20, 2014 11:29 pm

Thank you gentlemen, really appreciate it.

I haven't looked at it yet (tough deadline this week) but am now fairly certain it's the slave cylinder pushrod (as Frank from O1 confirmed). Everything was set up properly when the clutch was replaced last year, and it worked perfectly, no parts were changed since and nothing was worn out as the car has been at the paintshop, so it's logical it will be the adjustment, especially since I was told they set it up tighter.

I must say I had assumed the slave cylinder was self adjusting, like the modern ones, so I am really grateful for the info and support from you who posted here. Another lesson learned. Thank you.

Adi
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