Author Topic: Another stupid question (Read 6835 times)

Dr_Snooz · « **on:** December 05, 2010, 11:04:35 am »

Do I really have to open the diff and pull the drive axles to check the rear brakes? If so, what sorts of seals, gaskets, crush washers, etc. should I be prepared to replace while I have everything open? Sorry for the stupid questions. I've searched here and Google and Youtube and Metacafe and GM's service manual and every place in between looking for how to do this, but no dice.

I just did the front brakes and had to replace the brake hoses because they were disintegrating. It was great fun. They are bolted inside the frame rails and getting your hands between the fuel pump and frame rail and numerous assorted hard lines to loosen them was joyful fun. Then I rounded off a bleed bolt in the rear so I get to pull the wheel cylinder to get it out.

Woohoo!

beastie_3 · « **Reply #1 on:** December 05, 2010, 11:47:10 am »

Yes you do...i know it sucks. OK just kidding. No, after you remove the wheel, the drum should come off. if it doesnt, then go take your parking brake off. Turn the star wheel in the hole on the back side if they are still too tight. Or use a big hammer.

choptop · « **Reply #2 on:** December 05, 2010, 12:48:02 pm »

1/2- no. just remove druam as stated. May have to back off adjuster depending on how worn the drums are. On full floating axles on 3/4 and 1 tons, the axle does have to come out, but not the diff cover.

Dr_Snooz · « **Reply #3 on:** December 05, 2010, 04:34:56 pm »

Quote from: choptop on December 05, 2010, 12:48:02 pm

1/2- no. just remove druam as stated. May have to back off adjuster depending on how worn the drums are. On full floating axles on 3/4 and 1 tons, the axle does have to come out, but not the diff cover.

Thank heaven! So I can pull the drive axle and not have to worry about securing the pinion shaft and removing C-clips inside the diff housing? That's a huge load off.

I have the 3/4 ton axle (14 bolt) and the drum looks like this:

So I remove all those bolts inside the lug posts and pull the axle. I assume that inside is a very large nut that's bigger than any socket I have. Does anyone know what size socket I need?

Are there any other seals or whatnot that I need to plan on replacing? I'll probably repack the bearings while I'm in there.

Thank you!

Russ130 · « **Reply #4 on:** December 05, 2010, 04:55:05 pm »

There are 2 nuts and a washer in between them, you can use a screw driver and hammer to get the nuts off if you don't have the special axle nut socket. You can remove the wheel cylinder without taking the shoes off.

bobcooter · « **Reply #5 on:** December 05, 2010, 06:50:02 pm »

There is a metal gasket that goes behind the center piece with all the bolts. When you take the bolts out, you can pull the axle straight out. Putting it back in may take a few tries because it's kind of hard to hold it level going back in. I would replace the gasket. If you are not having any problems with the rear end other than the brakes, there is nothing else you need to remove. It's surprisingly simple.

Lt.Del · « **Reply #6 on:** December 05, 2010, 08:56:57 pm »

Quote

Re: Another stupid question

that's not a stupid question. I didn't know that. I do have a 91 3/4 ton 4x4 sub, but luckily my drum just slides off with some coaxing w/ a mallet or hammer.

Dr_Snooz · « **Reply #7 on:** December 05, 2010, 09:19:00 pm »

Thanks everyone. Last question (I think), is there anything special I need to know about how to re-tension the wheel bearings? Like on the front, you have to torque the spindle nut to 12 ft-lbs and then back off 1/6 of a turn to tension the bearings correctly. Is there anything I need to know like that for the rear wheel bearings? I usually read this kind of stuff in the shop manual, but either it's not in the GM manual or I'm looking in the wrong place for it.

I think the rear bearings are lubed by the diff, so I don't need to repack them or anything. Is that right? (Oops, that's two questions. Sorry.)

Dr_Snooz · « **Reply #8 on:** December 05, 2010, 10:25:51 pm »

I just found this, which is very helpful.

http://arrc.epnet.com/autoapp/9102/9102CH07_REAR_AXLE.htm

Dr_Snooz · « **Reply #9 on:** December 06, 2010, 11:52:17 pm »

I finally figured out that I have a 14 bolt GM Corporate full floating axle. Apparently, it's the cat's pajamas of heavy duty axles.

http://www.pirate4x4.com/tech/billavista/14b_bible/index.html
http://en.wikipedia.org/wiki/10.5%22_Corporate_14_Bolt_Differential

Autozone rents the socket to remove the lock nut (http://www.autozone.com/autozone/accessories/OEM-6-lug-4WD-spindle-socket/_/N-264l?itemIdentifier=2056&_requestid=1361051), so I can torque it properly when I reassemble it. The link above describes how, so I think I'm all set. I was able to disassemble everything today only to find out that the back brakes are a mess. I need new shoes, new wheel cylinders and new drums.

*Sigh*

reallyrusty · « **Reply #10 on:** December 08, 2010, 07:55:03 pm »

While your in there, you might want to replace the axle oil seals.

Dr_Snooz · « **Reply #11 on:** December 14, 2010, 01:26:29 am »

Finally got the brakes to 100%. I put everything back together to find out that the RR brake just wouldn't adjust right. I found that the plastic covering on the parking brake cable had started coming off and was bunched up against the cable housing, preventing the parking brake from releasing fully. I peeled back the coating and I'm all good now. The brakes are happy again.

Parking brake cable before:

Parking brake cable after:

News:

Author Topic: Another stupid question (Read 6835 times)