View Full Version : TR4/4A TR4 rear brake cyl. - what's this thingamajigger?

07-30-2012, 01:40 PM
hi all-

long awaited return and finally back up and getting my TR to a rolling chassis state before end of year.

I have the hubs/brakes completely disassembled and I'm about to get various new consumables, etc and start reassembly.

Upon examining the rear brake cylinders I noticed that the cylinder for each side has a small steel disc-like piece that is peened-in to the more malleable cylinder body. Almost seems to be some sort of steel bump stop.

Well, the peened metal broke off and now the little still discs (coin-like shape) won't stay in place.

how do you get those to stay in place? Do they sell new metal material I can use to peen them back in? can I use high-heat JB Weld? There are two little notches that appear specifically designed to accept something to hold these little discs in place.

can someone shed some light on how to appropriately replace these? thanks, wes

07-30-2012, 01:50 PM
JB Weld should do, until the next time you take the brake shoes off at least. With the shoes installed, the shoes & springs will hold the little metal disc in place.

Never seen them for sale separately, they are considered part of the cylinder assembly. New cylinders were readily available, last time I looked. Unless the bore is really perfect (which is rare, the combination of hygroscopic brake fluid and steel running against aluminum will usually result in pits in the bore); I'd just go for new cylinders. They are almost a consumable item, if you use DOT 3/4 brake fluid.

07-30-2012, 02:15 PM
Absolutely - at 15-20each buy new. The brake shoe fits in that slot, if bad its not worth fixing.

07-30-2012, 06:26 PM
Wes, do what they suggest, those discs should not come loose, but I recall that they were new when you bought the car. The whole system was rebuilt and or replaced.

07-31-2012, 07:45 AM
JVV- yes, that is not only my recollection, but my examination - the brake system looks to be in fabulous shape; just some minor clean-up and renewal needed.

of course, jerry - I am replacing all those god-awful zeibart covered brake lines and fittings!!!

thanks to everyone else for the vote of confidence on the high temp JBweld.


07-31-2012, 02:55 PM
The only good thing about all of that Zeibart stuff is that it did it's job. It's a pain to remove however. Ed and I got it that way. It's really a great body otherwise.