VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 1928 Chevy sudden wheel jam

I have a 1928 Chevy speedster car. I am working on the front and rear brake service brake adjustment.

Problem is the passenger side front brake. It will rotate and jam hard quickly and will not move.
Brake linings are in good shape, same for the brake return spring, and replaced the cam adjustment with new Billy Possum parts. Installed new bearings and seal kit. Cleaned all rust out of wheel drum. No adjustment of the brake cam is allowing the wheel to move without a jamming.

Why the sudden jam that appears at a half turn of wheel?

It was not jamming before replacing the new cam parts.
Thanks

Just guessing but I would check the brake drum for out-of-round.

One other question. Is the weight of the car on the axles while you are making the adjustments? In other words, is the car at normal ride height when you are making these adjustments?

The car is jacked up and level with car jacks.

Hi Rusty 37,
We are coming to the same conclusion as you that the brake drum maybe out of round. I did replace all of the hub carriage nuts and bolts. My plan is loosen up the nuts and see if I push the wheel and hub over the brakes to center the hub. I will follow up when we get this done. Thanks for the suggestion it supports what we are thinking. Paul

You are on the right track. If the axles are hanging from the frame that will affect the brake operation and adjustment.

I cannot remember if there is a "centering adjustment" for the brakes on your car. Sorry for the brain fade on my part. The last mechanical brake vehicle I worked on was a 1929 another brand. The first step for that vehicle was a centering adjustment.

Another point that I have experienced is that if the brakes are pretty far out of adjustment you might have to go through the process more than once. The adjustments need to be done in the correct sequence but they are not completely independent.

We played a game of musical wheels and the front passenger side wheel would not go over the brakes on the driver side. The driver side wheel hub would go over the passenger side brakes.
We took apart the passenger side wheel to separate the brake hub. We used a level and discovered that the face of the brake wheel hub was bowed out.
I have no idea of how this happened, but I did replace all of the wheel carriage bolts. Maybe I over tightened them?
Next, we played a game of Thor and used a large hammer to work the metal from the top of the brake hub face to the center. Eventually, we were able to bring the brake hup face in and the brake hub slipped over the brakes. At least, we were able to get it completely over the brakes to seat.
I plan to bring it to a mechanic who turns brake drums. It took me some time to find a shop to do this process, as most cars have throw away brake hubs today.
I will follow up when the job is done and let you know how the process worked.
Thanks

One word of caution. A drum can only be turned a certain amount until it gets too thin.

The '28 Brake drums are stamped mild steel about 1/8" thick. If you turn it true that will create thin spots that will heat and cool at a different rate than the thicker parts, and also differently from the other sides drum. Before you go down that path I would suggest you remount the drum and hub assembly and check it with a dial indicator.

If you used a large hammer to work the face of the drum inward I cannot imagine it running true now, and suspect that was the root cause of the problem after you switched parts around. The face you hammered on is where it mates up with the hub. The best way to turn stamped drums is a shop that has a grinder attachment on their brake drum machine.

In my opinion you should source another drum/bearing hub and transfer your bearings into it. Used '28/'29 drums are fairly common and it might be a good idea to acquire a spare or two. New drums out of AU are available but expensive.

Please let the forum know what you find. There are other members going through the same process.

Yes, I used a heavy hammer. I have worked on truing up cord wood saw blades, so there is a procedure of working the metal out. I beat in an even circle from the top of the drum out to the center. Then from the center to the top of the drum.
I got the brake hub to go over the brakes finally, but no adjustment
Something, I never thought of is that the old brake linings wear into the drum and carve the inside of the drum to fit the existing brakes. This is due to the metal in the brake material. The old brakes wear into the drums and shape the drum to fit those brakes.
I have worked on model T fords and the brakes were lined with Kelvar. The Kevlar is flexible as it has to go around the brake band. There is not metal in the Kelvar, and the brake band is soaked on oil!
I do not plan to use this drum on my car. It is an experimental piece now. I plan to take it to my garage that has a large hydraulic press. You can get an even press on the drum face. I have a ¼ inch piece of flat steel I wanted to use to cover the drum face.
I am surprised that I could not find a garage or a machine shop that turned drums. The equipment is sitting in a corner covered with beer cans. The machines are not used with disposable brake drums.
Now, I have bought a used drum off of eBay. As far as I can tell there is no stamping company making new ones.
In order to have the drum move, I need to turn the brake adjusting nut all the way up on the treads. In my thoughts, this is not going to create an even pull on both brakes. The brake adjustment has to be equal on both wheel to break evenly. This is caused by the drum not being true.

Thanks for sharing those details. It spends like you have the situation well under control.

I agree that it is extremely difficult to find a shop that turns brake drums. I have also observed that there are fewer and fewer places that will even turn rotors. From a total repair cost perspective it is cheaper to replace the rotors. Plus new rotors are thicker so they are less prone to warp from heat.

About a year ago I had some drums turned. They were not heavily worn so the “ridge” on the open side was not very deep. Nor were they out-of-round. They definitely had been turned before but were not at the limit.

What the shop owner/machinist showed me is that he did measure a taper from the open face to the inside. The diameter at the open face was smaller than at the inside. His explanation is that the drum expands more at the open face when pressure from the shoes is applied. So there is not as wear on that portion of the braking surface. He turned them enough to remove that taper and the slight ridge. The braking was noticeably improved.

Well, this would make sense to me as there is more metal and a rea backing plate to keep the metal from moving when one applied the brake. Also, the drum backing plate is a heat sink by absorbing heat. The front of the drum is open.
I bought two used front brake hubs on eBay today.

Great progress!