VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 brake lining thickness

I am about to get my brake linings replaced. (Woven linings). Lining thickness is supposed to be 3/16 of an inch. Seems that is a little 'skimpy'. Should I use 1/4 inch lining in order to make them last longer, or will a 1/4 cause brakes to drag? My drums seem to never have been turned? Any comments would be appreciated. VCCA 18184

#1 may be too thick to get the drums on. 'Your stamped steel drums can not be trrned with a drum lathe.

#2 Unless you will be putting on 50,000 milis in the the next 20 years you will not wear out the linings.













































32

Good points, I'll stick with the original 3/16 inch. Thank You

I keep learning from this forum. I am interested in more details on Gene’s comments about turning the stamped steel drums on a brake lathe.

What causes that limitation? Can they be turned on a regular lathe that has enough swing clearance?

Thanks!

The steel drums need to be ground rather than turned.
The steel drums are already too thin and resurfing them will only make overheating them eaiser.

Why would you need to turn a drum? Unless it has really bad scoring that you might want to remove. Because the drum is already spinning and being abraded by the shoes, it is effectively being turned so it should be already round….. assuming it was running true on the axle…. Even if the shoes were not mated well with the drum, they would still wear the drum round…..

Comments?


Mike

The braking surface on a drum or rotor will smooth out and harden with use. Any brake linings - new or old will lose a signifcant amount of "bite" and in return your overall braking will be reduced. Picture sliding a brake pad/shoe on glass and then picture sliding it on concrete. Which one offers more "bite"? The rougher surface after machining allows the braking surfaces to wear-mate to match each other 100% so you have full surface contact and more brake efficiency from the increased "bite".

Time and heat cycles will also change the shape of the drum, and machining gets you back to a fresh start. Machining removes any out of round or taper inside the drum - both of which will cause only partial contact between braking surfaces. It will also reduce any imbalance that could be causing a vibration and sometimes you will find out very quickly when you turn a drum that it is junk (warped, thin, bent, etc) even though it looks fine to the naked eye.

In this particular situation as Gene has said, these particular drums are already on the thin side so turning is not as important as maintaining thickness so some measuring for anything odd and scuffing of the surface would likely suffice.

Good morning,

I'm helping my father with a 1929 touring car. He wants to replace the brake linings and adjust the brakes. I purchased a NOS package of front brake linings. It seemed confusing that the linings are flat...

Can someone tell me the proper way to bend them into shape (without braking them)? Do I have to soften them somehow first?


Thank you,

John

Heat the linings in hot water until they can be bent.