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RT
10-23-2005, 11:21
Since my original thread got a little off topic I just started a new one. New questions regarding brakes and bearings on the full-floating 14bolt rear axle in my 93 C2500. I tore the brakes/hubs down, replaced the bearings/races/seals. Installed new shoes (2.5"X13"), new wheel cylinders, hardware, and reassembled it all.

First question: I searched the forum on adjusting the "duo-servo" drum brakes and found the post back in 03 on adjusting until they drag and then backing off 33 clicks. I tried this and the pedal was very soft. My buddy is an ex-GM tech, he indicated that the auto-adjusters cycle with the activation of the parking brake. So I held the parking brake release and pumped the parking brake pedal repeatedly and it did exactly what he said it would. The soft pedal went away as the brakes self adjusted. The problem is the driver side is hanging up/dragging and the brake drum is very hot(too hot to touch) after a drive. I have tried backing of the star wheel adjuster and checked the wheel spins freely but it still is very hot after a drive. The passenger side is fine.
I removed the drum again to inspect and see what the problem could be. I could find no problems with the brake shoe install even after disassembling/reassembling it all again. The shoe still drags. Any ideas?

Second question: When I removed the axles from the hubs initially several ounces of gear oil poured out. I assumed that the gear oil is the lube "bath" for the FF hub bearings. Cleaning the hubs there was also heavy grease present so I assumed that the hubs operate in a combination grease/gear oil mix. Since I had to remove the axle/hub again to troubleshoot the problem in question 1, I noticed there was no gear lube present this second time. I packed the new bearings with grease when I installed them the first time. I did not put any addtional grease on the inside of the hub like I would normally do since I figured the gear oil lube would do the rest. Am I wrong? Should I have packed the hub with grease? Or does it take a while for the gear lube to make it down the axle tubes?
I did drain and refill the axle with fresh lube. Help! What the heck did I do wrong? Thanks, RT

DA BIG ONE
10-23-2005, 11:57
This link has all your answers; http://www.pirate4x4.com/tech/billavista/14b_bible/index.html

RT
10-23-2005, 13:28
Thanks but I already have that link and have read through it and the related 14bolt disk brake conversion page twice looking for the questions posted. Still don't have the answers.... RT

JoeyD
10-23-2005, 14:56
The rear bearings are oil bath lubed and should not have any grease on them.
As far as your rear brakes getting hot on one side, look at the side not getting hot, it may not be working correctly making the other rear drum do all the work. You should also check the shoes for even wear. Maybe something is getting hung up and causing it to drag.
The parking brake adjustment works great if the adjusters are greased so they move without binding.

rjschoolcraft
10-23-2005, 16:50
Make sure to top off the differential oil level. This is what lubes the outer bearings. If the level gets low enough, the outer bearings will starve.

RT
10-23-2005, 18:35
Well the grease is on them and it'll have to do as I'm not taking those hubs apart again! The brakes on both sides seem to be working fine. They will lock the wheels when simply spinning on jackstands and if I hammer the pedal on the road. I have rechecked the troublesome side and cannot find any indication that something is wrong. I am thinking maybe the shoes just need to settle in over a few hundred miles. I have seen brakes overheat from problems, they turn the drums/rotors blue and cook the pads/shoes. That isn't happening, the one drum is heating up but no more so than it would during braking. The diff took almost 3 quarts of lube with the fill plug side on a very slight downgrade before it started to dribble out. I parked on a slight upgrade today and poured in the last 1/4 quart. Anyone know the capacity of the 14bolt FF? Thanks for the help. RT

diesel joe
10-23-2005, 20:43
So where did 3 qts of lube go? It usually holds 4-5 qts. If you cleaned the hubs and bearings you need to pack the wheel bearings with grease,because just putting some gear lube on them and expecting gear lube from the housing to migrate to the bearings cannot happen soon enough. YOU WILL BURN THE BEARINGS OUT! If you don't want to grease the bearings, fill the rear end to full and jack up one side at a time, about a foot, and let it sit for about 10 minutes. Drop it level, refill, and do the other side. Recheck lube after sitting level for a short while.

Some brake shoes do not fit the drum correctly, right out of the box, and will indeed need time to "break-in". They usually hit in the center of the shoe and have very little contact on the heal and toe. Or if the drums were not resurfaced the new shoes could be hitting on a high spot that the previous set was not touching causing slightly more heat until broken-in. Hope this helps.

rjschoolcraft
10-24-2005, 04:09
You really should not grease those bearings ever. Pre-lube with oil then roll the diff through several rotations using the pinion (drive shaft). This will pump the oil out to the wheel bearings.

After 400 or 500 miles, you should drain and refill the lube to get the grease contaminated lube out as much as possible.

RT
10-24-2005, 16:41
Update:
I found out today the diff lube capacity is 3.5 quarts. That would certainly explain why the bearings didn't have any gear lube on them. Tried the manual, owners manual, dealership no one knew the capacity just the type of lube required. My favorite local parts place had the answer. Go figure. Thanks for all the input! RT