The Stovebolt Site Forums The Shop Area Driveline Help- getting off rear Drum on '51 3600 3/4T

Hey all need some advice

Going thru the rusty lines and brakes on my '51 Chevy 3600 3/4T, awaiting replacement set of SS lines, but one wheel cyclinder seems to be leaking as there is a few streaks of junk on the rim and tire when it sat for a good while. It could be from the end of the axle, but the drum needs to come off. The two little screws holding the drum to the outside axle flang came off with some penetrating oil, and then some propane torch heat and smacking it a good 40 times with a impact tool-thankfully they both came off. But now I cant get the drums to move. When spinning the wheel I could hear the brakes slightly drag, I with a brake adjuster tool, I backed off the brake pad to the most rear off all the way, and now no noise. I did the front pad, kinda guessing if I backed it off entirely. but the drum does not budge with two big screwdrivers put between the drum and the sorta flexible backing plate.

Do I need a puller for this? I have a puller for disc brakes but it's to small as it doesn't go deep enough to get to the back side of the drum

Any ideas or tools that might help, or do I have to buy another puller?
Clem

You have 2 adjustments on those. You will need to back both off.

If the drum refuses to budge after a fair amount of massaging, the whole hub assembly can be removed. Pull the 8 bolts holding the axle shaft in, smack the center of the axle flange with a hammer, and the axle will pop out. Then remove the two big nuts on the end of the rear end load tube and slip the hub, drum, and all off. You'll most likely have to do that anyway to change the grease seal at the inboard side of the hub and inspect the bearings. It's possible you're leaking grease as well as brake fluid.
Jerry

Thanks Wrenchbender, I moved them both back as much as I can it seems. I have a scrap wheel cylinder so I know which way to turn back the brake adjusters, one up and the other down, plus the drum spins easily now. Still no budge sadly. I think Jerry's way is the way I have to go next, maybe rusted on the axle some, and I've pried on twice with big screwdrivers against the backing plate. I might try with a puller if I can borrow it from a pro mechanic friend (sometimes will loan pals tools). If not pullers look like they are over $200. If I cant borrow a puller, will have to pull the entire axle. Will follow, thanks to both of you.

-Clem

If you damage the drum, chances are pretty good that you will not be able to buy another one so Jerry's method is the way to go.

Might be a good idea to elevate the wheel you are working on to keep oil from coming out the end of the axle.

Ed

Heres my usual way of dealing with rusted on drums. Put lug nuts back on flush with end of lugs to protect threads. Clean around the base of all the lugs and the large center hole with a smallish wire brush. Soak everything with a good penetrant- base of lugs, center hole and all small holes in drum flange. Start tapping on drum flange between all the lugs. Do that for multiple cycles, letting it soak for awhile between. The last function is to hit the outer flat face of the drum straight in with a large dead blow hammer or with a 2x4 and a heavy regular hammer. Hit and turn, hit and turn around the drum face. Not too hard but reasonably solid hits. The impact will usually loosen things after a fashion like when you removed the drum holding bolts. Patience and persistence will usually win the battle. Of course if that doesn't work or you're not up to it then fall back to Jerry's method. Like he said you probably should be or need to pull the hub anyway.

Those 8 lug drums are virtually impossible to replace, so don't take a chance on bending or breaking one with a puller. Get the hub off, and use a press to push the drum off the hub if necessary. Taking chances with shade tree methods where brake systems are concerned is like betting your life on a high stakes poker draw to an inside straight, except you're also putting everyone else on the road around you in danger. The very best brake work you can do is just barely good enough.
Jerry

I talked to a pro mechanic and he gave the same advice as DaveMcK38 said, but good idea to get the penatrating oil into the 8 lug bases and every hole over the next few days. And then do the rotate and tap. Interestingly he said that if you put a puller on the drum- you make the circle into an slight oval actually and you risk it pinching on the tight axle and being counterproductive, and you can mis-shape it.

But thanks everyone, didnt know that it would be hard to replace, so fingers crossed. And Jerry, thanks for the heads up to be careful and do quality work with these heavy beasts with relatively primitive brake systems
-Clem

Hey All, success !! Yest I put penitrating oil down each hole and around the studs (great idea), rotated it 90 degrees and added a little more. Let it sit for a few hours occ spinning it while I timed it and fooled around up front, then with a 2x4 and a good size hammer hit it moderately hard, 20 or so times in different places on the flat surface and wha-la, off it popped. I got scared not wanting to break the drum and have to find another (thanks for the heads up Master Gabster) and it's off !! now to find the leak, maybe the Oil seal at the end of the axel by the bearings. But this will be in a new thread it driveline later today. entitled: Help: leaking rear Rear Oil Seal

Thanks All for your help above, getting closer !!
- Clem

Congrats Clem, I was pretty sure it would come off. By the way that method of removal is one I learned at a Raybestos brake school back in the 70's not in someones back yard. The only drum I can ever remember using a puller on is an old VW rear where the splined hub is part of the drum that slips over the stub axle. Definitely not something to use on this type of drum. Now its on to the fun of pulling the hub off to check bearings and replace the seal.

That cocked adjuster cap on the wheel cylinder is a good place to start looking for a leak. Chances are there's a corroded or damaged piston behind it. Finding new Huck brake wheel cylinders can be a challenge- - - -they're definitely a lot less common than ones for the newer Bendix-style brakes.