Clutch fluid turning black..

[Paul bow]

Hi guys, noticed the clutch fluid bottle was really dark in colour. No leaks anywhere no fluid loss and the correct cohene pipe used. Can’t figure out why so dark cars only 1000miles since rebuild, every item is new except the metal pipe connecting from the master to the low pressure hose.. (new one on its way) any thoughts guys?
Pic of the fluid drained out ..almost looks like oil contamination…

[cactusman]

Hmmm....looks more like the rubber seal in either the master or slave is breaking down...and if so clutch failure is not long behind...

[RICHOT]

I had a similar experience a while ago and it turned out to be that the slave cylinder rubber was ‘worn’ even though it was supposedly a refurbished one!

Cheers,

Richard

[44DHR]

Paul,
Almost certainly the Clutch Slave Seal is wearing down. A common problem when potentially “generic” 7/8 inch seals are used as opposed to sourcing OEM parts.

The original Lockheed 7/8 inch seal :-



A generic 7/8 inch seal offered by various Sellers :-



Also when reassembling the Clutch Slave Cylinder check the bore for any rust or irregularities for the seal to catch on, especially common when bleeding the brakes as the seal could pass past the point of “normal” operation to encounter a different operating surface. I had all my old Brake and Clutch cylinders re-sleeved in Stainless Steel, which then came back with perfectly honed internal bores.
Cheers,
Dave

[Paul bow]

Thanks… Dave where can such an OEM seal be purchased from?
I Can’t remember …to change that seal can the slave stay in place and hook the seal out, once the adjusting rod has been removed from the fork etc.. its a tricky tight job down there to get that off !

[cactusman]

The slave has to come off. Don't think it's possible on the car. There is all sorts of grime and grit there anyway and cleanliness is next to godliness and long term reliability when reassembling the slave I'm afraid!

[Paul bow]

That shows the discolouration .. only 1k miles in with all new parts, I cut open the cohlene pipe to see if it was breaking down.. Looked absolutely fine.
For what’s its worth I purchased an original supplier Lockheed slave cylinder item, (prob made in back streets of India!)

[mgcjag]

Hi Paul...Worth investigating the Isuzu clutch lip seal mod...search on Jag Lovers..Steve

[Paul bow]

Steve. I did order a kit last night from SNG, but I noticed when inserting a cotton bud in the metal pipe it came out black.. being the original pipe I’m wondering if this is the culprit…? Anyhow whilst doing it I’ll change everything, don’t have the part number for that Isuzu seal ?
Thanks..

[mgcjag]

Plenty of info on JL re the Isuzu mod https://forums.jag-lovers.com/t/e-type- ... ade/387875

[44DHR]

Paul,
As per my photo, the OEM seal is pictured on the supplier’s box. If you look on their website it is shown as “Jaguar”, but on closer zooming in on their photo of the seal, you can see the “Lockheed” lettering.
Regards,
Dave

[david.coan]

I have just had similar, despite all new fluid change in November at a professional full check up and service. My investigation showed for me my master clutch cylinder seals failing, i think for mine it was not shutting off the reservoirs feed on operation of the clutch correctly, so some dark fluid going back up into reservoir on clutch operation. No leaks anywhere on slave or master. On removing the cylinder it was full of black dark fluid. Clutch peddle operation now transformed, i had not realised with the very slow degeneration the weakening clutch feel until changing gear also became difficult when hot.

[Paul bow]

Well I stripped the slave cylinder and replaced the seal, removing the old one nothing too obvious apart from a slight rash on the side of the seal (see pencil), a bit of crude in the cylinder, which was all cleaned up with a bit of fine emery cloth, replaced the old original metal 1/4” pipe and the cohlene and the bottle.. snapped the end off, forgot how easy they are to break..all good for now …
thanks for your help all..
Nb. The roller release bearing (rob beeres) for those that can remember with my carbon one failing 20 mins on rolling road, is I can confirm so far excellent, def no clutch judder and working as should, only 1k in at present, trip to lands end from Essex planned, then the NC500, should really confirm by the end of the summer.
Thanks guys