Clutch Pedal Issue

[Flying Falcon]

Hi.

Whilst out for a little drive at the weekend, there was a loud crack that came from the clutch pedal as it was depressed.  Since then, the pedal feels softer and there is a grinding noise every time it is depressed.  However, everything else functions normally.  I'm thinking some sort of spring issue, but was wondering if anyone else has had a similar issue and/or knows of an easy fix (not the most gifted person with a spanner!).

 

My Seven is a standard 120bhp K series Roadsport.

 

Many thanks,

 

Matt.

[Graham King]

Matt, apart from a clutch pedal return spring there's no springs on the clutch mechanism. You can check the return spring by removing the pedal box cover, it comes off with 8 screws so relatively straight forward to do with the bonnet removed. I doubt it's that though as it wouldn't explain the other systems you describe. 

I suspect it's the clutch cable itself that has partially broken, again this isn't difficult to replace, just a bit fiddly, you'll need to remove the pedal box cover for this as well and then follow the cable to the top of the bell housing. 

The other possibility is the clutch fork that has cracked and bent so the clutch isn't engaging/disengaging properly, this would require the engine to be removed to replace at which point you'd be best off replacing the whole clutch assembly anyway. 

I'd start by removing the pedal box cover and inspecting the spring and cable.

Graham

[Flying Falcon]

Thanks Graham.  I'll pop the pedal box cover off and have a look.  Would it be imediately obvious if it was the return spring or cable?

 

 

[Graham King]

Matt, the return spring would be immediately obvious, there's usually only one on the clutch pedal so you'll see it easily. The cable, may not be quite so obvious as it could be broken inside the sheathing but with the pedal box cover removed you'll probably be able to operate the clutch from above, or get someone else to operate, so may be able to better diagnose where the noise is coming from. The cable is linked to the clutch fork under a rubber boot on top of the bell housing, the rubber boot has a spring loaded clip in it that you will need to press rom both sides, the boot should then be able to be pulled back revealing the fork etc, you should be able to see better then what the issue may be. 

If in doubt I'd replace the clutch cable first as it's relatively cheap and easy before attempting anything more drastic. 

Graham

[Flying Falcon]

I've popped the pedal box cover off and it's definitely the cable.  Completely frayed at the end.  It's hanging on by two threads so it's a miracle we made it home!!

 

I'll get one ordered now.  Thanks again for your help!

 

Matt.

[Graham King]

No problem, glad it was obvious, a spare clutch cable, along with a throttle cable, is one of my "must carry" spares when I go on any longer journeys (e.g. Le Mans).

[Jonathan Kay]

When you replace the cable there's an adjustment trick for the angle of entry at the pedal box that minimises wear. I think there's a photo in the archives: let us know if you can't find it.

Jonathan

[paul richards]

I'd recommend carrying spare cables all the time. Even if you can't fix it yourself the AA or RAC man can if you have the cables. 

I suggest simply cable tying spare cables to the chassis diagonal under the bonnet. LADS TOP TIP. 

 

[Lotus Boy]

I'd also recommend fitting a pedal stop on the clutch pedal to prevent you from over stretching the new cable.

Drill and fit to the pedal box, then adjust the stop just past your bite point.  The idea is the top of the pedal - where the cable connects - will hit the round end plate on the stop when you depress, thus stopping it from going further than needed and stretching it. 

http://caterhamparts.co.uk/search.php?orderby=position&orderway=desc&search_query=pedal+stop

Cheers

David

ps I always still keep spare clutch and throttle cables in the car.

[Dave J]

big head gate bolt in B&Q  = 59p 

[John Vine]

This is what the Assembly Guide says about adjusting the cable:

The clutch cable is fitted with adjusters at both ends so that it can be adjusted at both the bell-housing and pedal box. Set the pedal box end so that a minimum length of outer cable protrudes past the locating bush into the pedal box then adjust at the bell-housing end until a satisfactory clutch pedal position is achieved (4 threads showing through the yellow bush is a good starting point). The clutch 'bite' point should be set according to personal preference ensuring that it is not adjusted so as to prevent the clutch from fully engaging or disengaging.

The important thing is to set the adjuster in the pedal box as described.  If too much of the outer cable protrudes into the pedal box, the inner is flexed too much and it's this that leads to failure.

You might also want to take the opportunity to set up adequate CRB pre-load. See this article in the Guides section.

JV