The Stovebolt Site Forums The Parking Lot Tons 'o Fun 1949 1 Ton AD Rear Brake Issue

Greetings you Cats and Kittens,
I have a 1949 1 Ton Chevy Truck. I am having an issue with the rear back brake locking up. Can anyone assist me with how to take the brake drum off? There are 2 screws on the cover, do those have to come out? Heat? Or Oil? Thank you!

Yes, they have to come out first. You’ll likely need both heat and oil if they’ve been in there a while. I’d heat it hot and give it a whack with an impact screwdriver and hammer. Usually they spin out easily with that. If that doesn’t work, try penetrating oil, soak a day, and heat again. Be sure your impact fits snugly. It is easy to strip the flat head area.

If all else fails, drill into the center of the bolt head with a slightly smaller diameter bit and try an easy out. This is my last resort.

Once out, you’ll have to back off the wheel cylinder inside the drum. On either side of the brake line on the backing plate, there are 2 hex head bolts. Those are the adjusters to back the shoes off the drum.

Have fun and good luck. You may or may not need it. 😎

Brake locking up? Check the free play in your brake pedal. It might be your pedal/master cylinder and not actually inside the drum.

Ditto what Fox said. I will just add that whatever you do to get the drums loose, do it carefully. Those drums for the 1 Ton are basically gone from everywhere. Extremely hard to find if you have to get another. Take your time with them and you should be able to get them off the truck. I struggled with my 1 ton some years ago like you are. Now I make it a habit to check them twice a year to make sure I can get the drum off when I need to. Good luck with your truck! Tom

Any luck?

For what it's worth, here's a guide to working with the Huck Brake wheel cylinders on your truck. Hope you get things sorted out.

Hello,
No luck yet!
Thanks you Fox checking in!

What I did with my 1 Ton rear drums was smack them on the flat surface between the studs with a good hammer. Eventually powdered rust began to emerge and that was a sign that the rust bond was breaking down. Then it was a case of turning and pulling and sometimes very lightly tapping on the drum. My truck had been sitting in the grass behind a barn for seventeen years and drums came off without heat. I would not use a puller or any excessive force on the drums.

I agree, Fred. Just to clarify, only heat the flat blade headed bolt that holds the drum in order to help it out.

On my 1-ton those retainer screws are countersunk and brass. Maybe someone replaced the originals with brass before I got the truck.

The San Antonio crew is planning a day to help her out. Just got to find a good day for a get together! We might be calling for help as she has the only 1 ton in the group.

Chris

Nicely done, Bolters.

I asked her to respond on here. The brake guys she has talked to stated that they need to remove her axle and that it is brake fluid getting into the rear end. It sounds like a load of BS to me. They said they have seen this before, but I don't believe they have even looked at the truck!

Chris

Hello!
No luck so far! Now the back rear brake locks and drags the tire.
I went to see a brake guy recommended by a restoration place. SW Brake and Alignment, when I stopped by and spoke to the owner he said he would have to pull out the axle. With my trusty Shop Manual I think he was trying to say he needed to pull out axle shaft. He seemed to think that the problem was in the back, not in the front part with the shoes, springs, wheel cylinders.

The second guy I spoke also thought that it was the back drum also and somehow creating a mud from the fluid. He also said that I would have to purchase a special tool, I think what he was referring to is the special wrench J-2222. It would also require changing the differential fluid. I would need to purchase the seals and gaskets. I called LMC and was 28th in the phone que. Any suggestions on other vendors?
They both sounded like they knew what they were talking about.

Thank you for your time! I am new to this vintage vehicle ownership.

Pam

I agree. BS. I would like it explained how brake fluid can get into the housing...sounds pretty “taking advantage of a greenhorn” sneaky to me. I’d look elsewhere. Wouldn’t it make you think that if the brake fluid is leaking all over, that it would create a lubricating paste that actually retards braking action? Not make it sticky? It did on my old Toyota.

I would still double check your pedal freeplay adjustment. Doyle1950 (pm him for further details) fought with your exact issue and he chased it for a long time. His brakes would pump up, lock, and he’d have to crack a brake line in order to alleviate the pressure/locked drum. It turned out it wasn’t the drums. It wasn’t the the axles. It wasn’t the wheel cylinders. It wasn’t an out of round/bent drum. It was the pedal adjustment. He found an “old boy” shop with an “old boy” mechanic and that guy had him whipped up right in 5 minutes flat.

It was like 1/16” difference or something ridiculously small like that. Check it. Your manual will have that spec.

Thanks Fox I've responded to Pam's pm. I would also call BS on the so called brake repair shops wanting to pull the axle.
Doyle

Hello Ton-ers,

Thank you for all your help and sharing your knowledge!!
On Saturday we were able to remove the front drum covers. The right back brake had a lot of brake dust and found none in the left. The brake pads and the inside drums looked ok. We bled both back brake lines. The color and some gunk came out in the fluid. But there was no air in the lines that we could see.

Spin inspection it looked like the back right wheel cylinder was catching and not releasing. I think our next step would be to replace that cylinder.
The one thing we did notice was that the brake line was also leaking, we think it was at the connection at the back of the drum. Is that a piece I can replace or do I have to replace the entire line?
Thank you.
Pam

I’d pull the brake cylinder, disassemble, and see what is in there. It might be gummed up with rusty crud from old brake lines. Wheel cylinder disassembly is not terribly difficult, just messy. No special tools required except for maybe a brake tool for the brake springs, but there are work arounds for that (vise grips).

The rear brake line goes from the wheel cylinder/drum backing plate and snakes down to a junction T on the rear axle. Brake lines are cheap and easily replaced. You can even get the pieces from your FLAPS store at a prebent/ pre-flared length so you don’t have to double flare the line.

If t’were me, I’d be pulling every line from the master cylinder to inspect and the wheel cylinders. The lines are cheap, wheel cylinders not so much (but rebuildable if decent), stopping when needed...priceless.


Going is fun, stopping is critical. I was sure glad I could stop one day when a doe and her fawn jumped over a guardrail in front of me on the approach to a bridge. Tires locked (Hucks), me cringing, two semi trucks behind me locked up because I was “going slow”, and the deer scrambling back to safety. Needless to say, those brakes were thanked, and those semi drivers backed up. WAY BACK.

I just used an impact with the correct bit, gave it a few whack with the hammer and out they came.

So if I follow correctly the rear drums have been removed and the shoes inspected. Good going! Don't stop there. It sounds like one shoe isn't moving (no brake dust).

One can buy 1-3/8" cups (at least one could several years ago when I bought my spares) and overhaul the wheel cylinders. You should also be able to still get kits that include new piston-return springs. Complete wheel cylinders were over $80/each last time I looked. I have run into aluminum pistons stuck in the bores from electrolysis. They will stick after a few months of sitting in a rainy environment. You can get them out by screwing a zerk fitting in the inlet and hand pumping the grease gun. You can also use shop air but risk shooting the piston across the shop. In any case, with the cylinder bare and clean take your handy dandy wheel-cylinder hone and smooth up the bores, ditto the pistons; then on reassembly coat the aluminum pistons with anti-sieze compound like you'd use for sparkplugs in an aluminum head. Avoid getting it on the cups. That cures the stuck piston problem permanently or at least for years and years. Use the same anti-sieze on the other fittings too, especially the bleed nipples; you can save yourself or someone down the line a lot of trouble. I'm presently setting up to drill one out of an expensive motorcycle caliper.

I have also run into flexible brake hoses plugged with crud to the point that the brakes won't release. There are only three of these on these trucks and they aren't expensive but be aware the NAPA part number listed for the rear axle is about an inch too short. The fronts are OK.

I agree with replacing all the steel lines. A tube bender is a necessity as is tube cutter and reverse flare tool. If you can buy all the lines for your particular truck, great but the tools give you flexibility. Some people like stainless but it's more expensive.

The brake push-rod length is important. If it's too short you won't get full pedal even with the brakes adjusted right up. If it's too long, when the pedal is released the master cylinder cup won't uncover the tiny, tiny relief port in the floor of the resevoir and the brakes won't release. This adjustment is easiest on the bench. Not all push-rods are adjustable. Mine is. This tiny relief hole is also subject to plugging up. Same symptom as the push-rod adjustment being too long. To fix: pull a hair out of your wire brush and with a pair of suitable pliers poke the crud out of the hole. Even your smallest drill bit is too big. Attention to detail is important. Keep plugging away.

Ok, brakes only lock up randomly so my guess is it is not a pushrod issue. Cylinder was replaced on passenger rear and it got slightly better, all hardware was good, all pads are engaging, brakes have been bleed.

We have not replaced all the brake lines as of yet. We had a mechanic tell us that it is probably the rubber lines and they should be replaced.

Chris

Hello Ton-ers!
I was so excited! That I replaced the wheel cylinder! Got the spring off and everything! The universal brake spring puller really doesn’t work for this huck brake set up! I learned what copper crush washers are and how they can be used once! And if you buy a multipack from O’Reillys make sure to check all sizes. A Dremel tool can help hallow out the middle of the washer if needed. I used a racket strap to hold the shoes in place and a cable tie to hold the wheel cylinder together. Putting the spring back on was very difficult, thank goodness I had a strong friend help out! I bled both brake lines in the back multiple times. Test drove and everything seemed good. We did a 90+ mile drive on Saturday, and I could feel a burr in the system but nothing stuck or dragged. Sunday I went out for a short drive and there in the Lowe’s parking lot, the tire started to drag! Yep, dragging the tire! Ugh!!!! 😟

It has been suggested that we check the rubber lines of the brakes next!

Wanted to give a big shout out to Keith, Chris and all the Stovebolters! Tommy, Fox, Buckkoo,Doyle! And the Filling Station in Oregon.

Thanks for helping the Green Girl and her 1949 3/4 Ton Tater Tot!

About rubber lines .I had a problem years ago the brake peddle would get harder the more you drive and stop .Finally one day the brake got so hot it caught the plastic backing plate on fire and the front brake on the one side was seized.the car was parked in a lot overnight and the next day it was fine .Ended up being the rubber line as it would not release all of the pressure and would lock up the one brake if it sat for awhile it would slowly release the pressure .The rubber line looked fine on the outside but was no good so if the lines are cheap enough it may be time to replace .

I am back ,Just another ramble but if there is only the one rubber line at the rear over the axle then I would think that both back brakes would lock up,if it was the rubber line.