2004 one piece drum hub issue. Sorry, it's still around ...

[leebowman]

I have a 2004 hatchback with around 100k miles on it. Just wanted to pass along some info on this and that. It might even be useful ...

I have one drum that's worn oversize (over 201 mm). I might even replace both, since the bearings might be ready to go. The following might be useful to know which you have w/o looking, if its a 2004. I read on the AutoZone webpage that for the 2004, the transition to the split hub / drum came about after the following VIN number (last 8 digits, see below):

In the Autozone Repair Guides, this info is listed here:
| Repair Guides | Rear Drum Brakes | Brake Drums | AutoZone.com

And stating that VINs prior to xxxx xxxx x5B426447 have the combined one-piece unit. I've also seen the ACDelco p/n of 177-0455, but not sure of which that refers to.

A further indication for the early design is the code J41 listed on the glove box sticker. If JM4, it's the later design.

According to local GM dealers, the one-piece p/n is 96473234, with a list price of $ 211.10

But ... that p/n crosses in their system to the later hubless units with some retailers, CarQuest for one.

Points:

• The one piece unit weighs ~ 11 1/2 pounds, the hubless weighs ~ 8 pounds.
• The bearing hole measures 25 mm, but the AutoZone ad, which shows a picture of the original hub (bearings and bolts), but lists the opening as 52.6 mm, the actual size of the hubless one. The ad is on this forum, or Google autozone + 21104.
• Also, the AutoZone lists the weight as 9.99 pounds, which is closest to the hubbed one. But is it? ...

If I order one online, I'd hate to get the wrong one. Any thots?

[exodus0784]

Rockauto, great phone support. They'll let you know what's what.

[petrified.rabbit]

• Also, the AutoZone lists the weight as 9.99 pounds, which is closest to the hubbed one. But is it? ...

that might be the packaged weight, and not just the weight of the individual part. PLUS aftermarket parts can (as you pointed out) be heavier or lighter than oem..

I personally say update. Its the "same" cost one time, and cheaper every time after.

[YnotVW]

AZ is where I got the drum for my fiance's 04 when her bearing went to toast. And it was cheaper for the bearing and drum than just a bearing anywhere else! ~$50.

[leebowman]

I have one being shipped today from St Paul MN, via Amazon.com. Shipping weight 14 pounds, and provided photo matches the hubbed one. Ordered early yesterday standard O/N, but I hate it when overnighters go out on a Friday.

Anyway, I'll report back regarding the outcome, and probably do an Amazon review as well.

Cheers

[leebowman]

Done!

And it performs like it should. I noted a few things regarding the removed parts. The shoe wear was 95% on the front shoes [left on driver side, right one other side], with hardly any wear on the other ones. They wore out at around 95,000 miles. Most use was city use, but some freeway. And if the wear were more evenly balance [left and right shoes], they would have lasted longer.

The RH drum was shot, due to letting it go metal to metal, and exceeding its maximum allowed diameter by a couple millimeters. The max allowed is 201.0 mm, my new drum was 200.0 mm exactly, and the re-used one was at 200.6. I didn't turn it, since it was worn evenly enough to reuse as is.

The original drums are one piece. The replacement one was two piece, a hub and a drum bolted together, making subsequent replacement easier, if you choose to replace drum only and reuse existing bearings. The two are dimensiionally the same and interchangeable however. And this is for 2004 only.

I took photos, and plan to post a step by step, with some cautions and suggestions. Anyone know of a good place to post something like that? I did notice that what I found online, some of it copied from a manual, was sparse in details, and skipped some essential stuff. My step by step, if I complete it, will be much better.

Cheers

[djtommyknox]

Hi Leebowmen / Members,

I am having a heck of time with my rear drums. I have a 2005 Aveo LT... however the code says J41, so I believe they are one piece (I discovered this after trying to pull the drum with a puller). What parts do I need to replace? How did you get into the drum/hub to get to the shoes, springs, etc??? I removed the drum/hub from the axel... by removing the 4 bolts on the back of the hub. My parking brake is still attached because I can't get into the drum/hub. Any help / photos etc are GREATLY appreciated! Thanks! Tom

[leebowman]

"I am having a heck of time with my rear drums."

I hear ya. First, remove the center nut [32 mm, or 1 1/4"]. Un-dimple the rim on the nut before breaking it loose.



The drum can then be slid off, but if the shoes have worn considerably into the drum, causing a lip at the rear of the drum, it may be difficult to remove. Wiggling helps, but I had one drum that was grooved considerably, due to driving for awhile metal to metal [squaaawk ...], so I devised a simple puller (above). It was still a struggle!

You can see the grooves and the loose particles. It was considerably oversize, so I had to replace it.

The other drum was OK to reuse, since ID is still under 201 mm ID [max allowed]. If I had it turned though, It might have gone over that dimension. Didn't machine the inside since it was smooth and concentric enough, in my opinion. Some reuse an oversized drum, assuming it's only slightly O/S, but you do so at your own risk ...



Driver side. Top yellow arrow [horizontal spring] remove with visegrip, since extremely stiff, and might require a little help to remove. Notice I've clamped the shoes together with a bar clamp from Harbor Freight. Not really necessary, but at least I finally found a use for one! Then remove the vertical one that operates the ratcheting device for adjusting the shoe clearance initially. Then the stubby ones that hold the shows against the back plate. One technique is hold the shaft with a needle nose pliers, then rotate the disk behind it. There are tools made for that purpose, but this way works.

The right hand yellow arrow points to the plate that the parking brake cable is attached to. It comes out of its hole when you remove the old shoes. Bottom spring comes off easily with the two shoes, and reattaches to the new ones. When putting the new ones in place, you can use a couple small 'C' Clamps to hold them prior to attaching them to the back plate with the stubby ones [red arrows]. Then reassemble the ratcheting clip and threaded adjuster, then the other two springs.

Clean everything, spray with a light brake lube or silicone spray, and then reassemble.

Everything is the same on the passenger side, but reversed. Best to do one side at a time to avoid mixing things up, in particular, the threaded rod that ratchets outward to achieve the proper clearance. Reason being, that on the right side, it is a left-hand thread, while on the driver side, it's a right handed thread. If switched, the ratcheting will widen the gap rather than to set it properly.



Make sure the threaded cylinder turns easily, or clean the threads and lightly lube.

I tweaked the adjuster length to get a dimension that was just under the 200 mm of the drum, but if you don't have an 8" digital caliper to measure it with [again, Harbor Freight], you can do it by feel. Theoretically, the shoes could be fully retracted [minimum extension], and the ratchet would bring them to the proper spacing. But I preferred assembling it with a close fit to begin with.

When you put the nut back on, they say 140 - 150 ft/lb tension is required, but if you tightened then fairly hard with a breaker bar rather than a small ratchet handle, should be fine. Then re-indent the rim of the nut.

Hope this helps!

Get it done by Sunday nite ...

[petrified.rabbit]

there should be an access hole behind the star, or toothed part of that rod so you can wind the shoes back in, to ease removal of the brake drum.

[leebowman]

there should be an access hole behind the star, or toothed part of that rod so you can wind the shoes back in, to ease removal of the brake drum.

Here's a PDF file with some general information regarding drum jobs:
http://www.wilcoxbrosco.com/pdf/DrumBrakes.pdf

It shows a typical star wheel access port:



Yew, there should be one, but not on my 2004 hatchback. In this instructions (above), it says "Some cars have a filled access slot that must be punched out to gain access to the adjuster." That makes no sense either ...

Didn't see one, so when I did the job back in August, got the drum off using force. But tonite, I just had the thot, 'maybe I missed it.' So I jacked it up, and took a peek. Wide shot and a closeup.



It may be there with some Aveos, but not this one ....

Are there ports on later models? I understand that they now come with disk brake on all four wheels.