So, I have this '79 Chevy/GMC frankenstien of a tow truck with a big ole' 1
ton dually axle in the rear. I need to check the rear brakes! So I have
jacked up the truck and put on the stands, and I have taken off those
damnable back tires and wheels (which always seem to weigh more than I do)
and now I am looking at (rusty funky nasty horrid) brake drums that are
bigger then some cars entire wheels and tire assemblies!
How do you get those off?
I believe the rear is what one might call a "14 bolt full floater"? It has
14 bolts on the pumpkin cover, and it has the hubs at the end of the axle
houseings with the 8 bolts in them....
Do I need to take those 8 bolts out?
What will happen if/when I do? Will oil come out?
Is there a seal or three that I will ruin in the process that will need to
How big a hammer and how long will I have to hit these things to get them to
start moving? (I only wheigh about 140lbs and have little girlie office
worker arms myself so you should factor that into your estimate).
Perhaps a puller would be better in my case...and maybe some kinda
Thanks in advance...
I believe that there are inspection slots on the backing plate for that axle.
There should be one for each shoe. There is usually a tin or rubber cap over
the slots. To get the drums off you have to remove the axles which will result
in a small amount of oil being lost. Then you need a special socket to get at
the axle bearing nuts. There should be two one lock nut and then the bearing
adjusting nut. Then the drum should slide off. You may have to back off the
brake adjuster if there is a lot of wear on the drum to get over the lip.
Well I am not so much worried about the shoe linings, I need to get in there
and inspect the wheel cylinders and the parking brake mechanisims and all of
that other good stuff that exists in drum brake land.
I pulled the axle today and found behind it the funky 6 pin special nut
style of bearing retainer. So I need now to go out and find one of those
sockets. Any suggestions on where to get one of those besides the Mac or
Snap on guy?
Also, is it good enough to mark the retainer nut and simply return it to its
exact position when I put everything back together (as I am not changing
bearings) or will I have to reset the "preload" and all the headache that
Finally for what its worth this truck is somthing of a "toy" so I have no
qualms about tearing into somewhat new things and getting my hands dirty and
I haven't used the special socket in years. A good punch will
remove/install it no problem.
No, don't attempt to "mark" the retaining nut. If you have one
large nut with the small square dowel and retaining ring, then
you simply tighten the nut until you have no freeplay, then
tighten by hand further while turning the entire drum/hub
assembly. Then loosen the nut until you can feel that you
"some" freeplay. Now tighten the nut until you can feel that
the freeplay is gone. Have a look at the relative position of
the slots in the nut, and the one slot in the axle tube where
the square dowel will go. Back off the nut to the closest
slot, that will be where you want the bearing adjustment
> Finally for what its worth this truck is something of a "toy" so I
Well then, go for it. Just remember to install new seals (even if you
just pulled apart, found nothing to repair, and are putting it back
together again) and be careful installing them, as you can screw them
up quite easily. Then you "will" be replacing rear brake shoes as
they will have oil all over them.
Well I am not so much worried about the shoe linings, I need to get
Realising the axle bearing nut probably wasn't too tight I used the hammer
and punch method to remove the bearing nut. Hell, I almost hit the thing to
hard! It really is/was just past hand tight.
Egggs-cellent.....this is no too difficult...
Ahh the joys of working on an old truck....
Well what started out as a brake inspection has pretty much turned into a
full on rear brake and brake line! replacement from almost the master
cylender back. Even got new drums. The old ones were too shot to both
trying to machine. Everything came from NAPA, looks like total parts and
supplies is gonna end up costing me around $400 bucks, with the biggest
chunks of chainge going to drums (~$130 each) and shoes ($99 for the set of
Regarding the line replacement, one had blown out from corrosion, the rest
garbaged themselves as I attempted to remove each fitting.
Anyway hopefully when all is said and done I will be able to put myself
through the windsheild in a manner of speaking when I hit the brakes! :)
Thanks for the heads up on the hub bearing seals. I would not have thought
of that on my own.
In the end, this actually hasn't been too difficult a job. Nasty dirty and
grimey, but not too difficult.
PS. In doing online research I found a good website on the GM 14 bolt
corporate which was a lot of help as well, lots of pics, torque specs etc.
etc. http://www.pirate4x4.com/tech/billavista/14b_bible /
I would suggest purchasing a "Chilton" or "Haynes" manual for your model
they are available at most auto parts stores.
I have a manual for every vehicle I own.
well worth the $10-$15 dollars they cost.
This is a good suggestion, but these manuals are written for people that
have *some* basic mechanical knowledge. Some things are explicit, with good
photos. Some things are vague so you should already know what they mean.
I just snug up the adjusting nut while spinning the wheel, then back it off
slightly about a 1/4 turn. Then depending on what style lock nut you have.
(some have a tin lock that you bend over some have a ring with holes in it to
line up) you may have to adjust it to line up. Then install the outer nut and
tighten it up good. then bend over the tin tabs, adjust your brakes, install
sealer on axle and reinstall, top off rearend oil. Some people put a little
gear oil in the hub of the wheel to prelube the bearings or after topping off
rearend jack up opposite side to get the oil from the banjo to the wheel and
let it sit for a few miniutes to fill the hub. Either way works ok.
Ok well, I guess I made myself sound pretty ignorant in my first post, but
it was in part an effort to be entertaining, I'm new here. I have been
shadetreeing for about 15 years, but mostly on German cars, not old american
trucks so I'm moderately competant I guess, but my knowledge is a bit
lacking in certain items. ie, I can tear down and replace drum brakes on a
car in no time, but with this truck i was like "who the hell took the brake
drums and replced them with these giant finned cast iron mixing bowls?! And
how the hell do they come off???" yah dig?
I have the Haynes manual (somewhere..can't find it lately)and I found it was
OK, but the year/make/model spread is just way too far for anything
PS. Quick poll, how many people have used a Haynes Manual and thrown a tool
across the room at the instruction "installation is the reverse of removal"?
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