1931 Pontiac Steeldraulic Question

[Guest dannla]

I got my brakes back together on the '31 Pontiac today. I took everything apart and had the shoes relined. I put the brakes back together and adjusted them per my 1936 Chiltons brake book. I have spent hours on this forum as well as others getting all the insight I can on these systems. I spent time to do things right; cleaned everything, deglazed the drums, lubricated friction points (other than the shoes of course!)

When I put the brakes together all had .035 between the anchor pin and the rigid side of the shoe. I used .035 welding wire to set the gap. I set the shoes at .020 at the centralizing cam and verified the distance was equal around that half of the shoe (rigid side).

When adjusting the brakes, I did not have a lever to hold the brake pedal down half way through its travel so I used the emergency brake lever to hold it approx. half way. I set the brakes at "heavy drag" at this level. Setting the brakes in this manner caused the brakes to have drag with no pressure on the pedal. I attempted to test it (drove it approx. 100 ft) and the brakes were tight when no pedal was applied and they would hardly stop the car when depressed.

I see only one way to adjust at the point to allow no drag when no pedal is applied but allow sufficient stopping power when the brakes are applied ; the brake adjustment rods which impact the .035 off the anchor pin. I have to believe that tightening the brake adjustment rods to allow greater mechanical advantage when applied is what I need to do. I can then loosen the knurled adjustment nut on the shoe for no drag when no pedal is applied.

Can someone confirm that I am on the right track? Is there something I am missing?

Thank you!

[Guest]

I have fifteen different books that tell you how to set Midland Steeldraulic brakes for fifteen different makes of auto. They differ very slightly. The main thing to understand is that toggle that applies the brake is like a scissor jack, it has no mechanical advantage when it is in a sharp vee (unapplied). That is why the anchor pin requires 1/16" clearance. The extra distance allows the toggle to flatten out and gradually multiply the force from the pedal. That is why this system has such a soft easy feel at the pedal but has great brakes.

Are you certain that you have the shoes on the proper side. The center rib on the shoe is not in the center and if the shoes are on the wrong side they twist and bind. I have an article from a man in Australia or New Zealand that explains which is the right way. I don't remember and have just come home after a 16 hour day so will look for the article tomorrow.

I always put a 2x4 on edge on the toeboard under the pedal and used my crank as a prop between the seat cushion and the pedal when adjusting the clearances. You may not have realized it but the emergency brake which operates on a different crank on the cross shaft and has about one inch more travel than the pedal.

Of course I suppose you set the rods and cables first???. Were you able to get two different linings for the shoes as they originally came with. I do hope you had riveted linings put on.

PM me if you like and when I locate the other article tomorrow I could fax it to you. I never had troubles with my brakes (three inches of pedal travel would lock all four wheels) except once when I relined them and mixed the shoes up. I could not understand the problem until I read this article from downunder. Then it only took a few minutes to fix things.

I have consistently got eighty or eighty-five thousand miles out of a reline (five times) and only had to readjust the shoes about twice in that time. My Grandfather got 99,000 out of the original shoes.

I logged out and did a google search. Hugh Venables part way down this forum http://www.pontiaczone.com/forum/archive/index.php?t-19846.html has the answer about which side is which side probably even explained better than I can.

Edited October 2, 2013 by Guest
additional info available (see edit history)

[Guest dannla]

Thank you once again, Tinindian. During my research on these systems, I read the article from the Australian or New Zealander. I am certain my shoes are one the correct side. I did not realize the impact of the e-brake being on a different crank on the countershaft, but will use the hand crank and a 2x4 as you suggested.

The shoes were relined with all the same material. They are riveted. Were there different friction materials used on each shoe? if so, who do you have reline yours?

I went out today and started over from scratch. The first thing I did was throw out the book (figuratively) and "wing it". I began by loosening up the knurled nuts on all the shoes, allowing them to spin freely. I then tightened up the rods, increasing the space between the anchor pin and shoes (increasing mechanical advantage). I set the pedal at half way (e-brake) and expanded the shoes to the same drag. I then released the e-brake and checked for drag with no pedal. I loosed the tight shoes with the knurled nuts to just where they had no drag. Then I tightened the rods to gain mechanical advantage. I took it out and drove it and it was much improved. I will fine tune tomorrow using the 2x4 instead of the e-brake, but I think I am on the right track! I think I need to increase the mechanical advantage a bit, but I am close.

Thank you for your help! I'm sure I will be reaching out to you again soon!

[Guest]

The lining on the leading and trailing parts of the brake band were different and had a different coefficient of friction. I would have to read through all my literature to get the exact wording but I believe the leading part of the shoe had rougher lining so it would help the self actuating react quicker. I have had very good brakes on my car except for one error on my part. None of the relines though were ever as nice as the original linings.

I see in Buy/sell you need some hub caps. Read my reply there and send me a PM about how many you need.