1929 Master 121 Brakes

[rotus7]

I'm bidding on a 1929 Master 121 rolling chassis with some additional body bits.
The chassis has external contracting brakes front and rear and would like some input as to how powerful these brakes can be.
My plan is to build a 320 straight eight speedster from this base reducing the weight by at least 1000 lbs to a target of under 2500 lbs.
The drums are of a good size and the bands about 2.5 inches wide so they should have a a)reasonable surface area b)are out in the breeze so they should cool fairly well but c) will get wet with bad road conditions.
As always any and all input is greatly appreciated.

[raycow]

My only hands-on experience with external band brakes was on a couple of Mopars which used this design for the parking brake on the rear of the transmission. The drum was fairly small, probably no more than 7 or 8 in., but the brake worked through the rear axle gearing and was quite effective at stopping the car. It wasn't such a great idea for a parking brake though, because if you jacked up one rear wheel to change a tire, the car could easily roll off the jack. You had to loosen the wheel bolts before raising the wheel and tighten them after it was back on the ground.

Anyway, Mopar changed to an internal drum brake (still on the transmission) sometime in the mid 50s. The reason I heard given was that under severe winter conditions, ice build-up on the external mechanism could prevent the brake from applying (or maybe releasing). Frankly, I don't believe that was the real reason, because the external brake had been in use for at least 20 years prior to the change, and I don't think it would have taken that long to discover this kind of problem.

Ray

[rotus7]

Ray;
I greatly appreciate the reply.
A friend had a 33 Chev that still had it's original brakes which I remember as Very Scary Things...but then again they had not been looked after and the car was still at full weight.
To me if the weight is cut by a significant factor and new lining materials are applied things should be much better.
Besides they look so weird.

[stoneshrink]

I guess I wonder at why we'd consider that scary.... after all, disk brakes are external brakes as well (albeit different clamping direction).

[rotus7]

In the instance of the 33 Chev I Vividly remember rolling down a local long grade (4th Ave Hill) with a friend in the passenger's seat...both of his feet planted on the dash pulling on the Emergency brake as hard as he could.
Me sitting in the driver's seat with both feet firmly planted on the brake peddle also pulling as hard as I could.
When we got to a Stop sign about 2/3's of the way down the hill...and with NO chance of bringing the car to a halt...I just negotiated a right hand turn so at least we would be going in the same direction as anyone coming up our backside and not crossing traffic.
It's one of those moments that you remember Many years later.
As to the brakes on the 29 Buick I'm sure that by removing a bunch of weight and replacing the braking medium with new materials that reasonable braking power will be available.