Small Drum Rocky Mountain Brakes

[Boaski]

When I serviced the rear axle seals and bearings I got a better look at the rear brakes. I had to pull things apart due to grease and oil on the brake pads. Both sides were a little different in how the linkage was put together. I looked around on the internet for some pictures on how the linkage should go but I didn't find any pictures that looked quite like the same brake set up.

Does this look familiar to anyone?

[Scott_Conger]

Maybe I'm not paying attention but the only difference I see is that the left side is missing a coil release spring

[RajoRacer]

And the "correct" adjustment nut ! The nylok nut is a substitute.

[Scott_Conger]

oh, yeah...that too!

without the self-locking of the original nut bearing against the spring, that lock nut was probably necessary...I missed it completely

[Boaski]

I'm still trying to figure out what on this car is "normal" and what isn't. The last owner was the son of the guy that restored it, but there wasn't any transfer of knowledge when he got the car, so I think he did the best he could to keep it running. I'm still working on understanding the basics as I go through and try to get it back into fairly dependable operating condition.

The brakes appear to be the same design as AC Brakes but the main brackets are flat stock that has been formed rather than cast. I've found stuff about the ones from Larry in California, but I haven't seen any with the same bracket as I have. Since this car was restored in 1979 or 1980 the person that supplied these may be long gone.

Any idea of how much clearance there should be between the pad and the outside of the drum when the brakes aren't applied?

[RajoRacer]

Hard to set by "clearance" as most of the band isn't perfectly round so you want to be able to "wiggle" ever so slightly and "get a feel" for the pedal.

There was a fella from Florida by the name of Jess Bonar that had made a set of small drum external brakes for sale (and some other T parts) in about that time frame - he's long since left the planet.

[Scott_Conger]

scant clearance is required

primarily need to ensure that when released, they simply not drag to a point to impede motion or overheat (that's why the missing spring is kind of important as that will hold off the forward self-energizing portion of the brake band.)

there will be plenty of rebound and flexing in the linkage that even with little clearance, it might take a bit of pedal travel to fully engage. Personally, I'm not a fan of the "L" bent brake rod ends at the actuating lever...a better setup mechanically is a threaded clevis there. For now it is what it is

[Original Smith]

That doesn't look like a real Rocky Mountain Brake to me! I have small drum originals on all my cars, and would be happy to answer questions about the originals.

[Mark Gregush]

The lever looks wonky, as in too far forward and down. Look at the ad for Larrys AC brakes, you lever should be close to what is shown there. Looks like yours has a cupping nut or spacer just above the yoke that really shouldn't be there and the threaded rod between the yoke and adjusting nut on top, is longer then needed. Could be also, the pull rods are too short. With the levers where they are now, you are loosing your pulling power. Take the pull rods off and readjust everything. If you are going to use rods, you may need to make new ones. I would use yokes and pins at each end not as they are now.
http://www.mtfca.com/discus/messages/50 ... 1451332529

[Craig Leach]

The right side is close to correct, the long nut on the left may be the adjuster look to see if it has a groove in it to lock on the pin.
Correct if the brake pedal is not on the floor the rods are to short that angle is past where it should when applied. I have a very simular set &
they have springs on both sides. Im sure they are home made and they work great.
Never use Nylocks on brakes for any reason if the brake gets hot the nylon melts out & you have nothing to hold the nut from coming off
Craig.

[Boaski]

I see what you guys are saying about the need for clevis' on the end of the rods and for the rods to be as straight as possible. The external brakes are doing next to nothing at the moment so I need to do whatever is necessary to get them working.