Clutch Release Bearing Pre-load

[David Mirylees]

Any ideas on how to get a decent CRB (correct) pre-load on a 1988 chassied car? (old type with no pedal box housing/cover)

cheers

[John Vine]

Ah, a subject dear to my heart. 😬 If you don't have a pedal box, are there any other possible mounting points for the tensioning spring(s) near (that is, behind) the top of the clutch pedal? I'm not familiar with the 1988 chassis. Can you post a pic?

 

JV

[anthonym]

Amusing, thought I might find you in here John. I was going to find a link to your extensive respondes to me in 2009. But nothing like the man himself :-)

[jakeandlizzy]

John, can I have a copy of your article with pics on how to add the springs to standard chassis (mine is 2002) with a standard crb?

 

This may very well help David as well,.

[jakeandlizzy]

Ah, nevermind, here they are -- had to go through a mess of threads:

 

here

[David Mirylees]

John, Thank you for the help!

Pic here Bulkhead - not a pretty sight but a well used 7 :-)

I can fabricate any required bracketry but at first sight I can't see how I retain the "release" area of foot on pedal towards the upper end (level with the other pedals).

Cheers

 

[John Vine]

Hi David,

If I understand your "release area" comment correctly, there's no free movement in the clutch pedal as my mod takes up all the slack in the clutch cable. When you disengage the clutch, the tensioning springs hang loose and have no effect. As you engage the clutch, the springs are gradually brought under tension, and will apply the required 80N-120N pre-load when the clutch is fully engaged and the pedal is at rest. Looking at your pic, could you attach a little right-angled bracket to the inboard edge of the mount that supports the brake-fluid reservoir (where your speedo cable is tied)? If so, you could hook up the springs between this bracket and the pedal clevis pin (to look like this).

 

If I've misunderstood something, please say.

 

JV

[John Vine]

Quoting anthonym: 

Amusing, thought I might find you in here John. I was going to find a link to your extensive respondes to me in 2009. But nothing like the man himself :-)

😬

Quoting jakeandlizzy: 

Ah, nevermind, here they are

The Photobucket images are low quality. If you want, I could send you the original Word document.

 

JV

[Revin Kevin]

David,

No need for a bracket or second spring, just re drill the location hole for the spring in the pedal closer to the point at which the cable attaches, IE increases the mechanical advantage. Simple!

 

Chris

[John Vine]

*arrowup*That would certainly work IF the spring rate was high enough. But I think the spring shown in David's pic is there solely to take up slack so that the cable doesn't pop out of the clutch fork down in the bellhousing. Even when attached to the clevis pin, it's unlikely to exert more than 15N -- much too low.

 

JV

[David Mirylees]

Thank you John - it all becomes clear now :-)

The additional bracket for a couple of springs looks like a perfect solution (and for me the simplest) - just a case of sourcing the ideal springs to get the required tension then.

 

I appreciate the offer of the Word doc. I'll blatmail you my email address.

 

Very many thanks!!

 

 

[Stationary M25 Traveller]

Did something similar for another Sevener recently - he found suitable clutch springs in stock at a local car spares shop - designed for use on old Fords, I recall.

[John Vine]

David, this is the spring you need (x2). Word doc on its way.

Edited 19Jul17 to fix broken link.

JV