98 k3500 Rear Drums

[SinCity3500]

First, apologies if my question have been answered, but looking for the expertise of this forum.

Are the wheel hubs supposed to come off with the brake drums? It seemed to be the only way to get the drums off (along with the axle). I bought new drums, and they don't have the hubs, and now I have no idea how to get the wheel hubs out of the brake drum.

Also, how long are the rear wheel hubs supposed to last?

Finally, it seems there are weights welded to the drum? Is that normal and should I consider trying to save the drums?

Pictures for reference

 

[b454rat]

You have press fit drums. Need to drive the studs out, then the hub/drum will separate. The hubs are bathed in oil from the diff, so it's critical that the level be checked and filled. Wouldn't worry bout the weights.....

 

[SinCity3500]

I'm assuming heat with a block of wood and a hammer to drive the studs out?

Also, how much movement should be in the wheel hub bearings? I am getting a little side to side play with the inner/outer bearings, not sure if a little movement is normal. I'm assuming these are the OE hub assemblies and will replace them, just will have to wait for shipping.

 

[AuroraGirl]

First, apologies if my question have been answered, but looking for the expertise of this forum.

Are the wheel hubs supposed to come off with the brake drums? It seemed to be the only way to get the drums off (along with the axle). I bought new drums, and they don't have the hubs, and now I have no idea how to get the wheel hubs out of the brake drum.

Also, how long are the rear wheel hubs supposed to last?

Finally, it seems there are weights welded to the drum? Is that normal and should I consider trying to save the drums?

Pictures for reference

I thought the axles brought gear oil to the ends?

all I know is that my wheel bearings/hubs are bathing because my 14 bolt on my trailer has as much gear lube as it would fit by jacking up one side, capping the other, and pumping the sucker full.

I dont have axle shafts tho, woudlnt recommend if you had shafts.
by the way, 4 inch hole saw and snowmobile crossing signs make perfect 14 bolt caps.

 

[Schurkey]

If it's like my '97--and I think it is--the drums are "riveted" onto the back-side of the hubs using the lug-stud knurl. So, yes, the hubs come off, the bearings come out, and it takes a "special tool" to assemble/disassemble the whole mess. You'll want fresh grease-seals; and you'll want to inspect the area on the axle that the grease seal rides on. Like all seals of that sort, the rubber lips of the seal will cut a groove into the steel they ride on. You'll need to adjust the clearance on the bearings using the big hub nut and that "special tool".

Theoretically, you're not supposed to re-use the lug studs. The whole system sucks mightily. It's a service nightmare. It assures that the drum doesn't come off if the lug-studs all break. If the lug studs all break, I'm not sure why having the drum in place is so important.

Mark the drum in relation to the hub so it goes back together in the same relative position.

Drums sometimes have weights on them; most drums have machine cuts to lighten them for balance. I'd expect the new drums to be pre-balanced and ready-to-go.

That's a job I'll be doing this spring. MY plan--subject to change based on how much wear I find--is to leave the hubs and drums together, mount the whole damn works on the drum lathe, and cut the drum/hub as an assembly. I won't split them apart unless I absolutely have to; and in that case it'll be new drum(s) going back on. I'm not expecting problems with the bearings, which is good given the questionable quality of today's bearing selection. I'd rather have "good used" GM original bearings than brand-new Chinese crap.

And, of course, new wheel cylinders, new shoes, verify the backing plates, probably new hardware/springs...'Cause I don't want to dick with this again for a decade or more.

 

[Schurkey]

I'm assuming heat with a block of wood and a hammer to drive the studs out?

Probably not. I'd expect a hydraulic press, with the back-side of the hub/drum supported with a big socket or iron pipe so you don't distort it under pressure. I'm kinda guessing that the studs will pound holes into the block of wood.

I've seen guys hit the studs with an air-hammer; again the drum/hub better be supported on the back side so it doesn't distort. Overall, not my first choice.

I've seen guys swing the biggest hammer in the shop directly onto the studs. Not at all recommended.

Also, how much movement should be in the wheel hub bearings? I am getting a little side to side play with the inner/outer bearings, not sure if a little movement is normal. I'm assuming these are the OE hub assemblies and will replace them, just will have to wait for shipping.

Check the service manual for bearing adjustment.

Mine says to tighten adjuster nut to 50 ft/lbs while spinning hub in opposite direction that you're turning the nut. Back off 1/4 turn, retighten to 13 ft lbs. Then align "closest" adjusting nut slot with keyway. Insert key. Install retaining ring.

I wouldn't replace the hubs/bearings unless there was an actual problem found. But that's me. There is such a thing as metal fatigue; but I'm more afraid of Communist Junk than metal fatigue.

 

[454cid]

It looks like your hubs and drums are just rusted together.

When I pull my drums off (on my SRW K3500) I always make sure the mating surfaces between the hub and drum have anti-seize on them.

JD7 brakes on the 3/4 ton trucks have the drums on the back of the hubs, "pinned" on with the studs. SRW JB8 brakes have slide on drums, and I assume DRW do too. Your pictures look like srw drums, to me.

Those are some big weights on the those drums.... have you replaced the drums before?

 

[454cid]

Also, how long are the rear wheel hubs supposed to last?

Forever. Theyr'e not a wear item. You replace the bearings and seals. It's not something I'm looking forward too. That's something I've never done.

 

[SinCity3500]

This whole job is getting me closer to putting in a rear disc brake conversion. As Schurkey said this is a nightmare of a design. Got it all back together, and went to replace the diff fluid as part of this whole mess, and am now looking at methods to get the diff cover off as it was RTV'd and is mightily stuck on. What I thought was a Saturday afternoon job has now leaked into 14+ hours of cursing and smashed knuckles.

Thanks for the info to everyone who posted, it was a big help, and I've definitely learned more than I cared to know about drum brakes, especially on these trucks, but knowledge is power.

I ended up buying new hub assemblies, with new drums, and will look into bearing replacements. Hopefully a month or so down the road I can get the new pieces pressed together and get the whole new drums/hubs on as that was my original plan. For now I'm reusing the drums/hubs/bearings with new shoes and hardware.

 

[AuroraGirl]

all im gonna say is that sounds like a lot of noise, sounds like perfect time to upgrade to discs. hopefully you dont ever need to park on grades with a load