VX clutch problems a mystery

[Don Cook]

A mystery. 2.0L XE with Caterham dry sump bell housing. I recently replaced the clutch slave cylinder. The old one (14 years and 14000 miles) would leak when not used for long periods like over winter. So whilst the gearbox was out for a refurb I decided to fix it.

 

On the first run out after about 100 continuous miles the clutch pedal became spongy and the bite point moved progressively further towards to the bottom. When I had a look the clutch fluid was black so I drained it out, purged as much of the remainder out as I could and refilled with fresh DOT 4 fluid. The spongyness disappeared and everything was fine for about another 100 miles then the same scenario again and again.

 

Each time the fluid was black but with each refill, less black.

 

Each time the fluid level was the same as when filled.

 

If I stop the engine then after a short time say 30 mins the pedal is back to normal which tends to indicate a temperature element.

 

I never had any such issues with the old cylinder.

 

Anyone have any idea what is going on?

 

Cheers,

 

Don

 

[Paul McKenzie]

Don,

 

Tons about this in archives. Basically it's almost impossible to replace the seals without damaging them. Email me your address and I'll send you a short description of what me and other VX owners did.

 

Paul

[David Brown]

Hi Don, trust you got home ok without having to top up too often. Was a great driving weekend just a pity about your problem.

 

Did a search and see that you have some history on this from 2005.

 

David

[Don Cook]

Hello Dave,

We got home without any problems. I didn’t bother to refresh the fluid any more as that only fixed things for a short while. The clutch was still working but the pedal was virtually on the floor. When setting off from standstill I could pump it up to reasonable position with it in neutral.

We stopped over at the Crieff Hydro and ended up taking in the Yorkshire dales. Got home Monday 16:00 hrs.

Again what a fabulous few days. We’ll definitely have to do it again.

Cheers,

Don.

 

[Don Cook]

Anymore ideas?

Plan to start with the easy bit first. Master cylinder and work downwards.

[EFA]

Best idea is an external oil tank, a wet sump bellhousing and a cable operated clutch.

 

You'll find wet sump bellhousings are hard to find for this reason.

 

Aves and Steve Mell have been known to hoarde them though....

[Don Cook]

Thanks EFA,

Point is that it's been more or less trouble free for the last 12 years so why the issue now. I don't particularly want to make quite a significant modification if it can be fixed.

Cheers,

Don.

[Paul McKenzie]

Don,

 

As per my email, did you check the condition of the bore the slave runs in - if it's pitted due to acidic clutch gases or scored due to grit, then no amount of new slaves or seals will cure the problem.

 

You're obviously going to have to pull the engine out again anyway, so I would wait and see what you find, and go from there. If the bore is damaged a good engineer can sleeve it to the correct dimensions for the new seals.

 

Paul

[Don Cook]

Hello Paul,

I've not been able to check the bores yet but from memory it was fine when I replaced the slave cylinder a few weeks ago. What I can't get my head around is why this should start now after 12 years of running with the old cylinder.

Cheers,

Don.