I was idly looking at one of the parts dealers websites this morning and spotted a mention that rear brake adjusters are really hard to find, and that replacements are over £1000, if available. Is this right? That’s a worry, if it is - I’d best dig out the box mine are in and see if they’re useable. How can a pair of adjusters be so expensive?
I’ve also noticed that the four front axle cylinders differ in price quite dramatically, from £30 to around £90 or thereabouts. Any recommendations - should the cheap ones be avoided?
From memory discovered that alot of repro cylinders are a different size bore , so they should be replaced as a set . That can be tricky if you have to replace a single one in the future not knowing if they are the same .
I had all my 7 cylinders resleved in stainless.
Thanks Jim,
Interesting that the diameters are different - that would affect braking performance (although not necessarily for the worse, although Jaguar spent a lot of time developing the system) and would certainly require that the sizes don’t get mixed in the future. Why on earth would the repros be different - unless it’s a metric thing.
Did you re-use the rear adjusters? Were your old ones OK?
I reused my old ones , they where good.
Hi Roger,
I think the price of over 1000 BP for a replacement rear brake adjuster is pretty outrageous and think there are plenty of used ones around for a reasonable price. I hope you find yours. They are amazingly complicated little devices for what they do. I compare them to the ones on my 63 Ford Galaxie which is simply a star wheel on a threaded shaft that spreads the brake shoes through a slot in the backing plate using a screwdriver.
Regarding the wheel cylinders, I also recommend that you have your originals sleeved in stainless, for a permanent solution to the inevitable corrosion and pitting problem in wheel cylinders. I have looked at the quality of repro cylinders (County) and they do not measure up to originals. Take it a step further and replace the piston with a stainless one if you can find them. The main problem with seldom used brake systems, as you most likely know, is absorption of water by hygroscopic brake fluid, which then corrodes brake components. Some say to change brake fluid yearly to prevent that, but that is often forgotten to do.
Wheel cylinders should ALWAYS be replaced with the SAME DIAMETER model. Yes, it affects braking, and yes, Jaguar and Lockheed worked out the sizes very carefully at the MIRA test track.
Vendors may sell you the wrong size, either not knowing or not caring. That very thing happened to me in my early days with the Mark V. I bought a rear cylinder from a foreign car parts store and the brakes never really seemed right, didn’t discover until years later that it was for a Mark VII, similar but different diameter.
The 140 adjusters may be the same as for some saloon models.
I’ve had success polishing my aluminum cylinders to a mirror finish with a hone with Scotch-Brite wrapped around it. I make stainless steel pistons.
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My thoughts exactly.
I’ve had a couple of driving days at MIRA, which is quite an experience. Not sure when the real proving ground stuff started up, as in 1948 when it opened it was just runways - but designers spend a lot of time and money choosing sizes etc. and I’d like to stick to them.
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