'93 K2500 Full Float Brake Question

[trbankii]

Searched the forums and got a few answers, but wanted to ask before I damaged something.

Pulling things apart to replace the brake pads on my truck. Wheels off, pulled the axles on each side. Pulled the bearing adjuster nuts on each side. No problems. Pulled the drum from the passenger side, again no problems. Went to pull the drum from the driver's side and it will rock slightly, but won't budge.

From pulling the passenger side drum, I don't see what would be holding it on. The drum spins freely, so it isn't that the brakes are sticking. There shouldn't be anything else to hold it in place.

Do I apply more force? Whack it? Or is there anything I should check before going the brute force route?

Many thanks!

[More Power]

Worn out brake shoes that put metal on metal will quickly wear away the cast iron drum. This can result in a deep groove matching the width of the brake shoe. Then, it becomes very difficult to remove the drum.

I recommend first backing-off the adjuster all the way. The shoes could still be cocked slightly, and still be locking inside a deep groove in the drum. Turning the drum over the brake shoes might allow the shoes to climb out of a groove. If the drum is deeply grooved, it's toast anyway. BFH, slide hammer, metal saw, prybar.... All of the above.... Torch as a last resort. :)

Jim

[trbankii]

Jim, thanks for the reply.

I was thinking about that, but it just seems more solid than when I've encountered that in the past. Of course, the 14b is about three times the axle I'm used to as well...

It was getting dark last night, so I stopped there. I'll have to see about backing the pads off and see what happens.

There is absolutely no ridge on the other side. Of course, the previous owner may have replaced that side. I would have replaced them both at the same time, but I realize not everyone thinks like that...

I'll see what I can find out tonight.

[trbankii]

Jim, once again, thanks!

Backed the adjusters out and it came right off. Fairly obvious that work had been done to the passenger side but not the driver's side. Some people... :rolleyes:

[Turbo Al]

I actually found this problem with a car I was working on that had gone through one of those 46 point checks through a respectable company, what they dont do is check all the brakes just one front and one back so if there is something wrong with them you just fix one side they recheck and they will pass it -- like you said SOME PEOPLE.
Al

[trbankii]

I pulled the drums off and then had to let it sit for awhile as I had some other things to do - and figuring that I'd need to buy a new drum, or two...

Got back to it and looked at things closer. Something didn't seem quite right about the "ridge" where the one side had worn down - really worn down. Started picking at it and the "ridge" flaked off...

More investigating and it seems I had a seal leak. The oil was seeping into the drum and combining with the brake dust and caking up. The shoe was wearing it down where it was in contact with the drum (but likely not doing me much good to stoop) but was building up along the outer edge.

Cleaned it all up and the drum doesn't look that bad. Since you have to pull the axle shafts, my guess is that not only did the inspection stations only look at one front and one rear, they also only looked through the inspection ports instead of pulling the drum and never saw the leak...

All better now, but I also found out that my truck is a K2500HD after getting the wrong shoes the first time... AutoZone was very good about swapping the shoes for the right ones.

[Bnave95]

The Duro brand shoes are very good. The axle seals cost more than the ones from NAPA. BUT,At the time I did my shoes Auto Zone only had one seal. Used NAPA seal and had a leak. Had to pull that drum apart and resealed agan using Auto Zone. The new shoes with that seal were soked and NAPA would only replace the seal. Bad ideal or not,I ended up just cleaning the shoes with cans of brake cleaner. Any one I talked to said I had to replace the shoes. I have seen no problem with the cleaning.

[trbankii]

Ok, next question...

Any suggestions, tricks, or new curse words I can try to remove the snap rings inside the brake drums to remove the outer bearings? Since the one side was leaking oil through the bearings I want to clean everything out and repack them. Pulling the seals out was a whole bunch of masochistic fun, by the way. But the snap rings have me stumped.

I can use a long pair of pliers with a long nose to grab the bugger and pinch it together, but not enough that it will come directly out. I've tried pinching it together and then tried getting a bent putty knife under the snap ring to pull it up out of the groove, but it just snaps back into place...

Also, curious that this was moved to the 6.5 engine forum from the 2500 drivetrain forum...

[NH2112]

You'll need a set of pliers something like these:

http://buy1.snapon.com/catalog/item.asp?P65=&tool=&item_ID=6955&group_ID=768&store=snapon-store&dir=catalog

These things are a lot of fun - in order to get the outer bearing out you have to remove the inner bearing and race (the race by knocking it out from the outside end of the hub) then knock the outer race through the hub and follow it with the inner bearing. I have no idea what someone at GM was thinking of when they designed that! I guess it's offset by the bearing adjusters and pinion support bearing in the rearend.

[trbankii]

Nope, the typical snap ring pliers won't cut it. Have a couple pair and they just aren't heavy duty enough. I'm using a pair like the ones on the left in this picture:
http://s7.sears.com/is/image/Sears/00999373000?rgn=0,0,1800,1126&scl=7.2&fmt=jpeg
(They're about a foot long, by the way...)

As I said, I can pinch the ends of the ring the whole way together but cannot lift the snap ring out of its groove without it snapping back into place.

[NH2112]

Nope, the typical snap ring pliers won't cut it. Have a couple pair and they just aren't heavy duty enough. I'm using a pair like the ones on the left in this picture:
http://s7.sears.com/is/image/Sears/00999373000?rgn=0,0,1800,1126&scl=7.2&fmt=jpeg
(They're about a foot long, by the way...)

As I said, I can pinch the ends of the ring the whole way together but cannot lift the snap ring out of its groove without it snapping back into place.

Those aren't typical snapring pliers, they're almost 16" long and have a locking pawl to keep the ring compressed by some way other than main force while you're removing it. I've used them to remove countless 14-bolt FF snaprings like you're working with, and also from turret rotation gearboxes in boomlifts (among other things.) I know they're strong enough to remove the axle snapring because on the first turret gearbox I rebuilt I never put it in a press to take spring tension off the plate and was able to remove it while under pressure. :p

[trbankii]

Ahh...! Sorry! From the picture it looked like the typical ones with the dinky little points for those little sheet metal snap rings that have the "o"s on each end.

[trbankii]

Another question: I'm trying to pull these bearings out to clean things out and repack them, but now I'm being told that these bearings are lubricated by the gear oil in the axle and that they don't need to be repacked. Others are saying repack them because the oil won't get to them immediately and they'll burn up before it does...

If I don't have to pull the bearings, I'm quite content to leave them be and get this all back together.

Any general consensus?

[DmaxMaverick]

Another question: I'm trying to pull these bearings out to clean things out and repack them, but now I'm being told that these bearings are lubricated by the gear oil in the axle and that they don't need to be repacked. Others are saying repack them because the oil won't get to them immediately and they'll burn up before it does...

If I don't have to pull the bearings, I'm quite content to leave them be and get this all back together.

Any general consensus?

GM and many shops (as well as many DIY'ers) recommend packing them because they don't have/take the time to flow the lube to the hubs. I don't like the idea of the grease in the hubs because it can cause a "dam" and prevent migration of the gear lube under normal driving conditions, causing premature failure of the bearings. Lube migration is important to replenish the lube in the hub as heat and shear conditions deplete it. When I do a gear lube change, I elevate each side (10-12 inches) for about an hour to ensure the lube fills the hubs. Once that's done, I let it sit level for about an hour then check the fluid level in the diff. The above warning is correct, though. If lube isn't forced into the hubs, the bearings can burn up before enough can get there. If you don't have a jack that will allow you to elevate each side enough, you can use a ramp, or you can park the truck on a hill, then turn it around for the other side.

On another angle....
I have thought for some time about drilling/tapping a small hole in the axle flange so lube can be pumped in at the hub during service. A plug (or even a zirk) can be installed. This can also be used to "flush" the old lube during service. Is this "off the wall", or am I just thinking thorough?

[JohnC]

On another angle....
I have thought for some time about drilling/tapping a small hole in the axle flange so lube can be pumped in at the hub during service. A plug (or even a zirk) can be installed. This can also be used to "flush" the old lube during service. Is this "off the wall", or am I just thinking thorough?

Not off the wall. I remember working on big floating axles where the flange bolts had sealing washers on them. Pull the bottom bolt and the oil came out. Fill from the top...

[DmaxMaverick]

Not off the wall. I remember working on big floating axles where the flange bolts had sealing washers on them. Pull the bottom bolt and the oil came out. Fill from the top...

That's where I got the idea. I wouldn't want to necessarily drain at the hub, although that might be a nice bonus. The viscocity of the lube would require a rather large hole, and I was thinking about something around 1/4". I can force the lube in under pressure, and let it drain through the drain hole in the diff (or cover, if no drain hole). Instead of drilling the axle flange, perhaps it would be better through the hub, between the flange bolts?? The only thing I would be concerned about is the structural integrity of the flange or hub. Wouldn't want to create a failure point.

[trbankii]

DmaxMaverick, many thanks for the reply. This just seemed like entirely too much work to go through just to pack the bearings and what you say makes sense. I'll proceed as you suggest! :)