Carrier Rear Brake Drums

[Lynn Eades]

What happens when your drum gets hot? Does the sleeve spin?
Not saying it cant be done, just have some safety concerns.
What is a brake? a device that converts kinetic energy into heat (which is then disapated into the air)

[RichardT10829]

I know but I would imagine that the hub would need to be glowing to get the sleeve to fit, is he going to be driving the carrier hard enough and long enough to generate that kind of heat ?...... I suppose a key way could be machined between drum and sleeve


twas just a thought, I am sure an engineering firm would be able to give the in's and out's

[Phil Waterman]

Hi All

I vaguely remember hearing that brake drums were at one time were sleeved as an alternative to new ones.

Temperature differential need not be that great. Putting new starter rings on flywheels only requires heating the ring to 350F with the flywheel at room temperature. The trick is to put the ring gear on in one smooth movement as once contact is made the ring cools and shrinks.

Cheers Phil

[Lynn Eades]

That may well be the case, however the production of a cast iron ring, followed by the machining, fitting, and finish machining, to end up up with a somewhat weak result just wouldn't be worth it. Especially in this day and age, where questions would be asked, if a failure happened.
To go to the trouble of casting the repair ring, you may as well cast a complete drum.
Another avenue could be to turn the outside of the drum, and shrink on a steel "support" ring, which would be safer. This would allow a greater bore size to the drum. I dont think you'll want to do this either.

Kevin, turning out the drums and fitting thicker than std. linings is common. Modern drum brake vehicles have a maximum oversize. Back when the carriers were in wartime service, you replaced with a standard part. Your drum has a strengthening rib on the outside.
What you need to do is ascertain the original diameter, and compare that with what O.S.your drums will clean up at. From there is the hard part. Is that O.S. acceptable from a safety point of veiw? (I dont know who you ask)
Once that's decided, then the rest is easy. An O.S. brake will work better than a std. one. (bigger effective dia., and bigger surface area)
You will need to fit the o.s. linings, and have them ground to fit exactly, the drum radius.
In theory both sides should be done the same size to ballance the brakes, however, I dont think you could tell the difference. It is probably better to take the minimum out of each one, as it might still give you room for doing it all again later.
I wouldn't put shims behind the linings. Every separate piece (including sleeves in, and rings on the drum) is a barrier, or potential barrier to heat transfer.(the faster this can happen, the more efficient is your brake)
Some of the heat from your linings is disapated out through the shoes. A thicker lining of one piece is as good as it gets. Bonding is good as it does away with the rivets, which would be the biggest single reason for having to turn out the drums.

[kevin powles]

Hi, Thanks for the advice guys, I think I will go with oversize shoes, the drums themselves have a perfect finish and run true, I will get some shoes made and then run them in with the track off and brake on, I done this on the tank hunter and it bedded the brakes in well. I think the drums have been turned out so just that inner chamfer had been lost. Some previous log puller had modified the expanders to get more travel, I think i mentioned this before in another thread.

cheers kev.

[Richard Farrant]

Originally Posted by kevin powles

Hi, Thanks for the advice guys, I think I will go with oversize shoes, the drums themselves have a perfect finish and run true, I will get some shoes made and then run them in with the track off and brake on, I done this on the tank hunter and it bedded the brakes in well. I think the drums have been turned out so just that inner chamfer had been lost. Some previous log puller had modified the expanders to get more travel, I think i mentioned this before in another thread.

cheers kev.

Kevin,
Get your local motor factor to do the job, let them measure the drums and get the shoes relined thicker then profiled to fit. Remember the modern lining material is unlike the old asbestos, and will not bed in half as quick. In fact it does the opposite my hardening if you try to do it too quick.

[rob love]

I will second Richard's advice, and add to it that why would you have nice clean drums, nice clean shoes, and then subject them to the excess heat trying to set them in. Bring the hub and drum in with your shoes and let them either shim the linings if they are going with rivets, or else install thicker lining material and grind it to match the radius.

As a mechanic, I use to spend a lot of time removing the glaze from brake shoes. Why would you want to restore a vehicle and start off with the problem before you even get it out of the shop?