Vx clutch slave cylinder (help Arnie)

[Beej]

My problems continue..

 

(reminder 1993 vintage, registered 1998, Vx racer, dry sumped with the concentric clutch slave built into the bell housing)

 

having fitted a nice shiny new AP rigid ceremetallic driven plate and Helix uprated cover to accompany my new slave cylinder, I really thought my clutch problems were over.. ha ha, foolish me!

 

After just 300 miles, the new slave cylinder is p*ssing out fluid from both ends, so we have the engine out AGAIN.

 

It looks as though the O rings just aren't thick enough to provide a proper seal. They barely sit proud of the grooves. In fact, i would suggest they don't really sit proud at all. Certainly there is plenty of sideways movement when fitting the unit into the bell housing casting. Of course, I didn't check this before I fitted it, it never occurred to me that a brand new part might not be correct.

 

Has anyone had this problem before. The guys at redline (who kindly supplied the part) seem to think that there may be different versions of this component - the one I have been supplied and fitted is green, apparently they may also come in different colours!!

 

Does anyone know what the correct colour/spec part is. Does anyone know how thick/proud the O rings should be?

 

Help, I need the car for Llandow on saturday..

 

 

thanks

 

Mark

[Chelspeed]

Arnie doesn't use the slave cylinder built into the bellhousing / dry sump tank, he uses the Titan concentric release bearing as do I.

 

The only person I know who uses the same slave cylinder / bellhousing / dry sump tank as you is Vinnie.

 

Alternatively try talking to one of the race teams who were around in the Vauxhall race days, eg aryliam, hyperion, ratrace or arrowstar. I know they used to all have hours of fun with the clutch seals on this type of slave so they should know all the tricks.

[V7 SLR]

I think ECR uses the standard Caterham one. He posted a question recently about it.

 

I've trial fitted Vinnie's as I picked it up off Captain Chaos who sold it to him. It makes a good fit as far as I remember. I actually thought it was a decent piece of kit despite its reputation. I'm now keen to see the Titan one as it is obviously better.

 

Worcs L7 club joint AO.//Membership No. 4379//Azure Blue SLR No. 0077//Se7ens List Tours

 

[EFA]

Beej,

 

Roger Swift or Nick Dinsmore are experts in this field.......

 

Fat Arn

Visit the K2 RUM website

See the Lotus Seven Club 4 Counties Area Website here

 

[Beej]

brilliant - thanks. How do I get hold of these guys?

 

I am not familiar with the Titan concentric release bearing - whats the difference. It sounds pretty much the same (I'm pretty sure that Redline mentioned something about the caterham part being made by Titan).

 

Can I fit one as a replacement?

[NickD]

The Titan concentric release bearing is a unit made to fit inside conventional bellhousings and replaces the clutch fork and release bearing carrier. These units can't be fitted inside the Caterham dry sump bellhousing.

 

The Caterham-supplied slave cylinder for the dry sump bellhousing is also made by Titan (as are many other parts - sumps, bellhousings, oil pumps and steering racks etc.), and there have been 3 different versions that I know of.

 

The first had a blue anodised outer sleeve with a (soft) plain aluminium piston and O rings seals inside and outside. The combination of the O rings and aluminium piston resulted in a very short-lived and leak-prone unit.

 

The second version had a red anodised outer sleeve and (I think) a steel piston. Not sure about the seals or longevity as I've never used this one.

 

The third (current) version has a green anodised outer sleeve and a steel piston. It has conventional square-section lip seals between the piston and sleeve, but still has O rings on the outside. This version also has a longer piston to accomodate the thinner release bearing which Caterham now supply (this might well be the only difference between the red & green units)

 

All this means that the only cylinder now available for use in the dry sump bellhousing is the green unit, and this is only available in one size and with one size of O rings.

 

Is the bore in the bellhousing still healthy, as I've seen bellhousings where the cylinder has fretted in the bore and left marks where the O rings seat? If so, you might be able to clean this up with very fine (1200 grade) wet&dry. Larger section O rings might also be available somewhere, although I've not investigated this option.

 

Most of the slave cylinder problems that I've had have been leaks between the piston and the sleeve and have been caused by pitting of the piston in the area where the seals seat.

 

These cylinders are not the most reliable item around, and using them with heavier clutch springs only aggravates their failings. Unless you can find some alternative O rings to try, then fitting a complete new cylinder is probably your only option.

 

Nick

 

 

[Beej]

Thanks Nick.

 

The complete assembly was replaced about 300 miles ago so I can't believe that the leaks are occuring between piston and cylinder. Its green. The one it replaced was green. There are no obvious problems with the bore of the bellhousing/sump tank. The factory line is.. "well it should work". Aaaarghhh.

 

I guess I will have to try and find some bigger/better O rings.

[Rob Walker]

I have had the misfortune of changing two slave cylinders on my friends VX this year. I think its quite important to use some high spec fluid as the cylinder gets very hot being integral with the belltank and close to the gear box input shaft. I used Castrol SRF last time and this seems to be lasting but will try Silicon Fluid next time as this does seem to have some lubriction properties which could help the seals last a little longer. Undoubtedly it helps not to leave the car without use for a long time as this allows the seals to stick in the bore so a couple of presses on the peddle each time your in the garage will help. IMHO its a crap installation and prone to early failure sorry.