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Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 1:41 am
by Triumph TR
I have a 1971 Traveler and am replacing the rear brakes. I found that the rear slave cylinders had seized in a partial extended position. This kept the shoes from being retracted enough to slip the new drums over the shoes. I am trying to remove the slave cylinders and I can’t get them to slid out of there retaining slot. Everything has been disconnected from the cylinder. The manual says to remove the lower half of the piston from the wheel cylinder and it will slide out from the backing plate. The parts are frozen into the cylinder and I can’t get the body to slide out. Almost looks like the axel hubs need to be pulled away but that can’t be right. Any experience with this?
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 8:11 am
by svenedin
As you've discovered, the cylinders slide in a slot in the brake back plate. You need to free the cylinder up so that it can slide in the backplate and then you can wiggle the cylinder out from the backplate. Obviously disconnect the hand brake. As you've also seen, there isn't much room with the hub in place but it is NOT necessary to remove the half-shaft and hub. Turning the hub to get slightly more clearance can help. If there is a rubber dust boot around the cylinder (which there should be) it makes it a bit more awkward but if the boot is falling apart already go ahead and cut it off. If by chance, you also need to renew the oil seals then by all means make it easier and take out the half-shaft and hub.
Stephen
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 8:13 am
by philthehill
Unfortunately pulling the hubs away from the back plate may be the only way to get the wheel cylinders out of the back plate. But before you do that try pulling the half-shaft away from the hub and turning the hub to get a bit more clearance - the hub flange is not completely round.
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 8:29 am
by svenedin
If you do have to resort to taking the hubs off, make sure you have what you need for the job before you start. You'll need the half-shaft O-ring and paper gasket, the hub lip seal, a new lock washer for the hub nut and a suitable tool for the hub nut. The old back street garage bodge was to drift the hub nut around with a chisel which many damaged hub nuts attest to. My hub nuts were mangled so I had to dress the damage with a Dremel tool and grinding attachment before the proper spanner would fit.
Stephen
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 9:01 am
by philthehill
Do not mangle the hub nut use the proper spanner.
This is a currently available and correct spanner to use when undoing the rear hub nuts on a Minor:-
https://www.ebay.co.uk/itm/167863166108 ... R-relqTZZw
There is no torque setting for the rear hub nut - it should be done up tight but not so tight as to strip the threads.
I am fortunate to have an original factory/Churchill hub nut spanner with original tommy bar which ensures that the nut cannot be overtightened.. The proper factory/Churchill hub nut spanners do come up for sale quite regularly on 'e' bay.
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 11:19 am
by myoldjalopy
I have always found the rear cylinders to come out OK, although sometimes requiring a lot of faffing and jiggling about. But I can see that, sometimes, it may be easier to remove the hubs as a last resort.
Re: Replacing rear brake slave cylinders
Posted: Mon Jun 15, 2026 11:20 am
by Mervin
If you are not aware, apologies if you are, the l.h. hub nut is a l.h. thread.
Re: Replacing rear brake slave cylinders
Posted: Sat Jul 11, 2026 1:18 pm
by 59Elva
I spent much of Friday before and after a noontime downpour removing and replacing the right rear brake from the pickup. The cylinder appeared frozen but externally clean and fresh. The parking brake lever was also very stiff. After removing the lever twisting the hydraulic piston freed it and tapping the cylinder against my vise eased it out. The bore and cup looked good after cleaning so I reassembled everything. It was a study in frustration getting everything together. The last was the worst. Getting the shoe retaining springs to hook to the backing plate. Im pretty sure there’s a tool for this and Im pretty sure I have one, just don’t know where it is. I struggled with needle nose pliers.
The pedal is low again after bleeding so more probably required. Braking is slightly better but not good enough. On to the fronts.
Re: Replacing rear brake slave cylinders
Posted: Sat Jul 11, 2026 4:29 pm
by Bill_qaz
59Elva wrote: ↑Sat Jul 11, 2026 1:18 pm
I spent much of Friday before and after a noontime downpour removing and replacing the right rear brake from the pickup. The cylinder appeared frozen but externally clean and fresh. The parking brake lever was also very stiff. After removing the lever twisting the hydraulic piston freed it and tapping the cylinder against my vise eased it out. The bore and cup looked good after cleaning so I reassembled everything. It was a study in frustration getting everything together. The last was the worst. Getting the shoe retaining springs to hook to the backing plate. Im pretty sure there’s a tool for this and Im pretty sure I have one, just don’t know where it is. I struggled with needle nose pliers.
The pedal is low again after bleeding so more probably required. Braking is slightly better but not good enough. On to the fronts.
viewtopic.php?p=718633&hilit=Beehive#p718633
See post for beehive spring tool
Re: Replacing rear brake slave cylinders
Posted: Sat Jul 11, 2026 4:41 pm
by 59Elva
Thanks Bill,
Beehive spring. I’ve learned a new term. The tool I remember was a multi function plier with a cup at one end of the handle. I think the “jaws” were meant to stretch the return springs. Another job where needle nose pliers are a poor substitute.
Re: Replacing rear brake slave cylinders
Posted: Sat Jul 11, 2026 10:24 pm
by Bill_qaz
59Elva wrote: ↑Sat Jul 11, 2026 4:41 pm
Thanks Bill,
Beehive spring. I’ve learned a new term. The tool I remember was a multi function plier with a cup at one end of the handle. I think the “jaws” were meant to stretch the return springs. Another job where needle nose pliers are a poor substitute.
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Re: Replacing rear brake slave cylinders
Posted: Sat Jul 11, 2026 11:43 pm
by 59Elva
I reused everything. I know the beehives springs should fit because I took them off. Working on the ground isn’t as easy as it used to be. Bifocals don’t help much either.
