Rear Brake Drum Drama

[94burb]

Hello All,

I have a strange problem. I just picked up a 94 Suburban K2500 and am just begining to start fixing it up starting with the brakes. I have changed the front disks (KVR) and pads(KVR carbon fiber) and lines (russell steel braded) and am quite happy with them. For the rear, I got stock drums and shoes from a jobber and got them put on. I didn't change the line yet but will do it soon. The thing was that the pedal felt really spongy after that but I didn't worry about it so much as I am still getting the feel of the truck. (Biggest thing I have ever driven).

Here is the main problem. I had the rear tires changed and the guy was telling me that the rear brake drums were not fitting properly. I take it to another garage(the guy who originally did them is locked up for DUI for the 13th time so i cant ask him anything, go figure) and we got the 2 kinds of shoes and drums for that year suburban. One kind matched the shoes and drums that I had already and the other one was too small.

Here is the catch. The drum doesn't seem to go on the hub all the way. There is a 2-3mm lip on the axle that the drum sits on preventing it from sitting flush on the hub. This makes it sit like .25in off the hub kinda. This also causes me to lose .25in off my bolts so when i am bolting up the rear wheels (8 bolt) it is very little stud available once the wheel is on. This cannot be too safe. Just by looking at the drum it seems that if the center was machined a few mm wider, it would fit correctly but I am not sure if it would touch the backing plate. This axle doesn't seem to be a 14 bolt floater that I have read about where the axle has to come apart to take the brakes off. It seems to have 8-12 bolts if I remember correctly. I am not to sure about that.

The other thing is that the shoes once installed, do not sit flush on the backing plate but actually have an angle to them. Looking from the rear of the truck, the shoes seem to slope toward the center of the truck from top to bottom instead of being parallel with the hub.

I suspect that the axle is not a suburban axle but I have no idea about what truck it came off. I know the diff must be geared for towing because on the highway at 100k it is showing about 2300RPM. I also want to change this to a lower gearing because this is more of a family daily driver than a towing vehicle and I do want better mileage if possible.

Does anyone have any idea about what is going on with my brakes? I guess once I figure out what axle I have it is as simple as getting the correct brakes but I don't know where to start.

Any help would be appreciated.

Thanks.

[catmandoo]

is it a 1500 or 2500,if it's a 1500 the axle has to be removed from the center by a c clip if it's a 2500 the axle is held on with 8 bolts!by you saying there was 2 sizes of shoes i'm gonna assume it's a 2500,and if so they do have a lip on them that the drum sets on and when i took mine apart i had to heat the drum around this lip to get it loose.it could be the drums were made wrong.as for the gears i turn about 2300 or so at 62 so i would think you are running the same gear i have 4:10 and they work pretty good unless your running freeway all day then 3:42 are in order,if you will ever be pulling a camper or such the 4:10 might serve you better.

[94burb]

Thanks for the fast reply,

It is a K2500. I do remember seeing 8 bolts on the axle but my mechanic told me it seemed like more but both of us are not sure so the wheel will have to be taken off again to verify. I got a jobber to give me 2 different sets of shoes and drums both listed for the 2500. The set that I had purchased from a different jobber and had installed before are an exact same match to one of the sets the 2nd jobber gave me to compare. The original drums that were on the truck when I purchased it, I dont have anymore to compare.

I do remember that the guy who first changed the drums said they were a real biitch to install so it may be possible he had to heat them as well.

I don't think the drums are made wrong as there are 2 different sets (mine from the first jobber and the loaner set from the 2nd jobber) that are an exact match. I do feel if the inside is machined a bit, it will fit. I can't see them fitting by me banging them on.

I'll take your advice on the gears. It is probably many other things I can do first before I should do that. I plan to keep this truck for a very long time.

[ees]

I to have a 94 K2500. I just repeatly replaced the rear brakes a few months ago. I had a heck of a time getting the correct drums. I was thrown by the fact that the last person to service the truck had used 2.5" wide shoes when it was supposed to have 3.5" wide shoes. I finally got it straightened out.

To uninstall my hubs I put the drums hub side up on the ground and put a 2x4 on the hub. Then one full force sledge hammer hit and they came appart. Mine new ones however slipped on perfectly without any extra force required.

If you are in doubt about what axle you have take a look at this page. It might help.

It Lives!!!


Around Noon on September 13th 2003 I test drove the car for the first time. There are still some loose ends. As I wrap those up I will focus more on updating this site as well as giving it a face lift.

http://tinyurl.com/yr7y3

[94burb]

Thanks for the diff link. I will crawl under when I get home from work to try and see what I have. I guess that if I do change the gearing, I have to change both the front and rear axles since the truck is 4x4.


Did your brake drums sit on top of the little lip on the axle or did it slide over the lip so that the drum was flush with the hub?

Maybe I need to bang the drums on the lip or somethng. At the moment they do not seem to want to go over the lip but sit on top instead.

This brake thing is really puzzling me.

[cruzer]

I know GM set up their brake drums for ff 14bolt rearends 2 different ways. I don't know the break down on yrs or even if there were differences in yrs. I have seen FF 14's w/drums that are attached to the hub. The axles have to be removed, then the spindle nuts remove to get the drum off. The drum will be held on to the hub by the wheel studs. You may have this design. The other way was that the drum slid off the hub like a semi floating rearend. No removal of axles or hubs. I don't know if the drums were different between the 2, but I suspect they are.

I don't think a bigger hammer is the answer.
You are having too many issues w/shoes & drums.
My guess is you have some or all wrong parts.

Just to cloud the issue even more, they made a
14bolt w/a 9 1/2" ring gear IIRC, and a 10 1/2"
ring gear. The 10 1/2" ring gear has bolts going around the pinion.

[ees]

My manual talks about having to press out each wheel bolt on a press and then press them back in. Mine was not like that. I had to bang it out due to rust, but it slid right on with no effort in the end. My drum went perfectly onto the hub pilot.

Are you sure you are hanging up on the pilot and not on the wheel studs? You might have the type that requires pressing on the wheel studs and installing the hub and drum as a unit.

Here are some pictures...


http://www.sofadog.net/6.5TD/images/completed_drum.JPG


http://www.sofadog.net/6.5TD/images/drum_installed.JPG

[TurboDiverArt]

Originally posted by ees:
My manual talks about having to press out each wheel bolt on a press and then press them back in. Mine was not like that. I had to bang it out due to rust, but it slid right on with no effort in the end. My drum went perfectly onto the hub pilot.

Are you sure you are hanging up on the pilot and not on the wheel studs? You might have the type that requires pressing on the wheel studs and installing the hub and drum as a unit.

Here are some pictures...

I "thought" to remove the rear drums on the 8-lug rears you had to remove the outer/center bolts first and pull the floater shaft, is that what it's called? Looks like you were able to pull the drums right off like a car.

Thanks,
Art.

[ees]

The old drums did not just slide off. You can see on in the background of the first picture. They were in VERY bad shape. I removed the drums and hubs as units. I tried all sorts of things to get them apart. I could not get them to fit well on our presses at work. I finally got frustrated and went the sledge hammer route. One hit and the hubs dropped out of the centers. I imagine if things had not been so rusted to start with I could have pulled them appart from the start.

[94burb]

Thats exactly what my axle looks like!! smile.gif

Thanks for the pics. That realy helped. My shoes are not that large for sure so I must have the 2.5in shoes. I see that your drum actually fits perfectly flush against the hub. Mine doesn't do that because it gets stuck on that lip and wont go any further. As well your shoes are parallel to the hub where mine seem to be sitting on an angle. For sure, I must have the wrong brakes.
I'll try and take some pics to post as well. Maybe this will prevent people from making the same mistake I did.

[cruzer]

Turbodivert, They made them both ways. slide off &
axle/hub removal. I suspect this is where the problem lies. I would think the drums would be specific to the type of assembly.

Instead of a press you can sacrifice a lug nut and put it on upside down and screw it on so that it will protect the end of the stud(almost flush) and then knock the studs out. To install the stud use washers,a lug nut and a impact wrench to pull them thru the hub and drum.

[Hye]

Pics look like my '94, too. Are they usually that greasy!?

Axle ID @

http://www.coloradok5.com/axleguide.shtml

Mine came from the factory with the trailering option; hitch, wiring, tranny cooler, etc.

[ees]

Since your shoes are on slanted is it possible you have 2.5" shoes mounted and should have 3"? How wide is the machined part of the inside of the drum? Of course this might not mean much as the drum could be wrong.

I was able to get my dealer to print me a list of the parts I needed based on my VIN. I didn't buy their parts, but it helped me confirm what I needed. The drums I ended up with were either $49 or $99 each at Advance Auto (can't remember which one ended up being correct). They are based here in Roanoke, VA and I actually had some friends help figure out exactly which one I needed.

I would talk to a dealer and see if they can get your any info to work from. If they are less than helpful just tell them you need a printed quote for the parts.

[94burb]

After seeing your pics, I am sure I have the 2.5in shoes. I remember when we were comparing them the 3in seemed to big because when whe put them in the drum on the ground, the pads stuck out a bit and were not flush. We did measure the inside of the drum but I cant remember the measurement. This weekend I will try and take a peak and take some pics to compare. I think the shoes and drum I have are wrong.

I am soo close now I can taste it.

[diesel joe]

I'm probably a little late with this comment but for what it's worth. there are several problems that can cause spongy/ soft brake pedal feel; the first one I noticed in your picture was that the long shoe was installed on the front; should be short shoe on frt. and long shoe on back. Second problem is something that isn't always known, brake shoe arch doesn't always match the drum arch; (shoe hits on top and bottom only or in center only) causing shoe to act like a spring when pressing against the drum incorrectly. Always bleed your brakes properly, and proper adjustment is a must.

Your parts problem is probably the difference between the 9 and 1/2 and 10 1/2 rear diff's.
I hope this info helps.

[94burb]

Some added info:

I think the truck has a 10.5 gear as the diff cover looks like the 14 bolt GM corporate for that application according to various diff identification pages. The guy at GM said that those only came in full floaters where the hub had to come off to take the drum off. He said because of that he figures its a 9.5in diff. My setup looks exactly like the pics, except i have the 2.5in shoes in there by mistake and my drum doesn't fit on all the way as it gets stuck on the lip.

Can anyone tell me if the 10.5 diff came with pull off hubs? Thats what I seem to need. I don't want to shell out anymore money till I am 100% sure I have the correct parts.