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SRW hubs full floater - bad machine work?

3500GMC

3500GMC

What T F, over
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Nashport, Ohio
Ok I think maybe I'm going more nuts. I'm a little pissed so bear with me.

Both rear hubs on my '93 are wobbly. Seriously, so much so as the damn things are causing the self adjusters to tighten the brakes until they bind. They get hot. Short trips empty of around 10 miles or so. The run-out is visible by eye. This is the flange surface where everything bolts to, drum and wheel. WTF? P-brake cables are new and not stuck.

I wouldn't think bearings would cause this...? My bearings are used but in good shape.

You literally can see the machined surface of the hub wobble. For shits and giggles I bolted the new drums (thought it was warped drums at first) BACKWARD and the deep offset of the 13x3.5 drums really exaggerate the wobble. Big time. When bolted on correctly BOTH new and used (turned 100 miles ago) drums grab and release as they rotate just like a very badly warped rotor/drum.

Anybody ever run across this?

This truck's a f'n lemon I tell ya...:mad2:
 
The obvious question is, are the brakes assembled correctly? There are several ways that they can be put together wrong that causes them to adjust out continuously.
I DID NOT want to answer this way. Just sayin'...
As to hub runout, IDK. That's usually bad bearings or bent shafts or some of both.
 
Hub bearings?
Last time I observed this in person it was a bent axle on a 1/2 ton. FF may not apply.
 
btfarm said:
The obvious question is, are the brakes assembled correctly? There are several ways that they can be put together wrong that causes them to adjust out continuously.
I DID NOT want to answer this way. Just sayin'...
As to hub runout, IDK. That's usually bad bearings or bent shafts or some of both.
Click to expand...

Yep, brakes are assembled correctly. New hardware, well everything, for that matter.

WarWagon said:
Hub bearings?
Last time I observed this in person it was a bent axle on a 1/2 ton. FF may not apply.
Click to expand...

True, FF does not ride on the axle, everything is on the hub and stub.

I guess this is the real question. Do bearings wear to the point of run-out and still be un-pitted and still smooth? I've never had 'em do this, but there's a first time for everything.

It's probably the hubs. When I had the backing plates off, the flats where the shoes ride was nearly worn through, had to weld 'em up and re-finish them. The shoes were working back and forth for quite some time. It's been like this long before I got the truck me thinks.
 
That's the hell of it. New drums do the same thing. The old ones were 'turned' during the 50 different things I done to the truck. Same deal.

For sure I will get a dial on it. I can see the run-out by eye. I'm kinda in disbelief.
 
Did someone mix up the rollers in the bearings inners and outers? Like where half the rollers on one side are bigger than the other side? It would only take one larger roller in the bearing... Otherwise rust in the hubs or bent hubs. Drums appear to not be the cause - not much left.
 
Lemon it is

Well let's see, 100 more g-damn dollars for bearings. Does it fix anything? Hell no. Bought new bearings and seals today and swapped out a side. Set up a dial indicator. The surface for the axle is out of whack right along with the lug flange...

Left side, .027" runout
Right side .018" runout

Here is a video of the driver side: http://www.youtube.com/watch?v=LdfLye8NIn0

Can you say wopperjawed?

So it's buy new hubs, or re-machine these. Geerrreatt!
 
WarWagon said:
Did someone mix up the rollers in the bearings inners and outers? Like where half the rollers on one side are bigger than the other side? It would only take one larger roller in the bearing... Otherwise rust in the hubs or bent hubs. Drums appear to not be the cause - not much left.
Click to expand...

The old bearings could go back in, really. They're just fine. And you're right, the drums are not the culprit. Reading my post I come off like it's a big deal, but it's not really... Guess I have a pair of FRIDAY hubs!! ;)

I'll fix it. Fix the fix that fixed the fixers fix!
 
ak diesel driver said:
any heat discoloration on them?
Click to expand...

Not that I can see. Diff oil was in good shape and up to snuff too. Pulling the hubs today to fixture them up to the lathe somehow. I marked them while on the truck so hopefully I can get them clamped true to the lathe to get a good cut.

Another note as mentioned in post 9, the bolting surface where the axle mates up has runout too, so I'll be facing that off in the process...

Fun fun.
 
Got one done. This hub was out .027"... I removed the inner oil seal and bearing race and it chucked right up to the lathe. Used the 3 jaw chuck. Put a dial on it to make sure the runout was the same as what it was on the truck. Locked it down and made a series of cuts until the two surfaces were true. It cut fairly easy with a carbide tool. Either forged steel or nodular iron. Definitely not gray iron.

Pics of re-machined hub, one halfway through the machining process.
.
hub2.jpghub1.jpg
 
Last edited:
Not hard to believe for me AT ALL.

I have never seen the like.

This thing should be like greased lightning when I'm done...:D
 
I'd check them for cracks. How do you bend hubs like that? Never mind how... Assume they were and check for stress cracks from it happening.
 
It's my belief that they were like this from the factory. These are some serious hunks of steel to just BEND.

Crazier things have happened, right?

I was trying to calculate how much deflection the AXLE had to put up with while bolted to the wobbly hub. Had to be 'not good'...

.027 projected out to 36"... Is somebody good at trig?
 
3500GMC said:
It's my belief that they were like this from the factory. These are some serious hunks of steel to just BEND.

Crazier things have happened, right?

I was trying to calculate how much deflection the AXLE had to put up with while bolted to the wobbly hub. Had to be 'not good'...

.027 projected out to 36"... Is somebody good at trig?
Click to expand...

I don't have my calculator handy in the house but it's:
tan<= a/b so tan<= .027/outer hub radius X 18 (radius of the tire outside). That sum is your max runout.
 
I was talking about the amount of deflection of the axle at it's splines when bolted to the wobbly hub. I could bet that it was binding the whole axle for quite some time.. Probably since '93..:rolleyes5:

I guess it's neither here nor there since the hubs are now zero runout.

See sketch.
.
DSC02520.jpg
 
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