Leaking master brake cylinder

Hello my fellow Jaguarist …

Lately working on my '89 XJ40 feels like I’m treading water and not swimming toward the finish line !

While my car has been up on jacks waiting for my harmonic damper to be rebuilt I just noticed that my master brake cylinder is leaking out of the end and running down the front of the vacuum booster (yes I’ve done the vacuum brake modification and I love it).

I hate to replace the whole master brake cylinder because I know it’s just a rubber seal issue. The problem is I can’t find a rebuild kit anywhere on line. A new master cylinder isn’t very expensive (less than $200) as far as Jaguar parts go but it seems a bit of a waste. Any ideas or should I just bite the bullet?

I hate to say it but more and more I’m looking at new and late model Jaguars on line. After 30 years my XJ40 is like a part of the family and because of the fantastic shape it’s in I’d hate to say goodby, but there reaches a point when it’s not about the money but the parts are just no longer available :weary:

This problem in obtaining parts is becoming a regular feature in the letters pages of the monthly JEC magazine. It’s not just XJ40 owners complaining, owners of more modern Jaguar models are also complaining, some owners have not been able to use their cars for months at a time while they track down illusive parts so if you are thinking of moving on to a more modern Jaguar it would be prudent to investigate the parts situation for whichever model you are considering first or you might end up in the same predicament you are facing now.
SNG Barratt are working with the JEC and asking members to compile lists of NLA parts needed to keep their vehicles on the road and print an update on re-introduced parts each month.
It annoys me that you can find every part for E.Types, MK2s Mk 10’s and most Series XJ’s and XJS models with ease, yet it’s impossible to find new rectangle headlights, wing repeaters and other vital parts required to pass the annual MOT test for a much later car like an XJ40.
With your master cylinder it might be worth cross referencing the part numbers for the seals with other car makes and models because Lockheed and Girling often used the same seals for many different master cylinders.


I recently replaced the seals of the master cylinder. It is relatively easy. Just remember to use a 11 mm crow foot wrench for the brake lines!
The seal kit is readily available. However, the two grommets for the reservoir are incorrect. Luckily, mine were in a good shape. I used this seal kit: https://www.ebay.com/sch/i.html?_nkw=autofren+d1117+&_trksid=p2380057.m4084.l1313
I ordered my kit from Estonian parts store for 4 € (~4 $).

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Found it …

Welch Jaguar parts had a rebuild kit for $79. So hopefully that will take care of the problem. Fortunately in the hierarchy of repairs on this car rebuilding the master brake cylinder ranks right down there with brushing my teeth :sunglasses:

I have a large amount of XJ-40 parts. Last parts department I bought was 25% XJ-40 and 80% new parts. Only about 10% are inventoried and put away at this point.
Email only: Sales@JagUSA.com

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Greg …

Thanks. good to know. I’m sure I’ll be contacting you for something sooner or later :smiley: