Bad Bearings In Rear End

[The_Dude]

Took my '91 in for an alignment and inspection. The chassis shop says that, at least, my axle bearings are bad and a good chance the rest are bad too. They want $600 to rebuild and say I'll probably need $400 worth of axles. Do the axles typically go bad with bearings? How hard is it to replace the axle bearings? The parts don't seem to expensive at latemodelresto.

 

[92 LX]

How do they know your axle bearings are bad? Is the rear making any noise? Something doesn't seem right, you shouldn't need new axles. Maybe just the seals are leaking???
I'd get another opinion.

 

[The_Dude]

They put it on a lift and say they're making noise. The shop has done a lot of work for me in the past. They're not cheap, but I do mostly trust them.

 

[Gearbanger 101]

You generally wouldn't know if the axles are bad unless they were out. Looking for abnormal wear, or pitting on the bearing ends. I'm thinking that they're guessing that the axles will be toast based on the condition of the bearings. Neither one of you will really know for sure till it's apart. Sounds like they're hoping for the best, but trying to prepare you for the worst?

 

[The_Dude]

Yes, that was my impression as well. They did say that, more often than not, the axles do go bad with the bearings.

 

[The_Dude]

If it's just the axles and outer bearings, I probably rather do that work myself. If it's the inner bearings too, I think I should replace the 2.73 gears with 3.55s at the same time. I think the shop is going to kill me on parts if I have them do it all.

 

[boostfrk]

If it's just the axles and outer bearings, I probably rather do that work myself. If it's the inner bearings too, I think I should replace the 2.73 gears with 3.55s at the same time. I think the shop is going to kill me on parts if I have them do it all.

I replaced my axle bearings a couple months ago...only took a few hours start to finish and that was lollygagging around. Like Gearbanger said you won't know if the axles are bad until you pull them out. Look for scoring or pitting on the axle where the axle rides on the bearing.

 

[rd]

If it is the outer bearings, they make a repair bearing that has a sleeve to go over the worn part of the axle. Ask around at a parts store. Changing the outers is pretty easy.

What symptoms did you have. My 89 notch seemed like it had a noise from one or the other going around a corner, so I pulled the axles. They and the bearings were fine, so I put them back in. Just make sure theres enough gear oil in there.

 

[2000xp8]

Here are my thoughts,
If you are going to mess with the rear at all, go all in.
New bearings, 31 spline axles with 03 cobra traction lok and 3.73 gears.

If the axle bearings are shot and you have driven on them a long time, likely they have worn down the axles, i know, i did it years ago.
If this started a week ago, i'd say you are fine.

Either way, do the rear once, and do it right.
You really don't want to pay to do rear work more than once.
No sense in digging in twice, and if you goto 3.73's while you are there, every penny will be worth it. Especially over 2.73's, it will feel like you have a new car.

 

[Gearbanger 101]

Here are my thoughts,
If you are going to mess with the rear at all, go all in.
New bearings, 31 spline axles with 03 cobra traction lok and 3.73 gears.

If the axle bearings are shot and you have driven on them a long time, likely they have worn down the axles, i know, i did it years ago.
If this started a week ago, i'd say you are fine.

Either way, do the rear once, and do it right.
You really don't want to pay to do rear work more than once.
No sense in digging in twice, and if you goto 3.73's while you are there, every penny will be worth it. Especially over 2.73's, it will feel like you have a new car.

While I agree that would be a stout rear end set up, 31-spline axles are pretty overkill for most applications. The 28-spline units will hold up fine through most power levels. Only when he really starts hooking up is he going to need something more "robust". If the guy hardly ever see's the track and is making under 300hp he's probably never going to have an issue with the stock axles. Even with Drag Radials. The stock trac-loc with upgraded disks is probably fine too. No sense using a hammer to swat a mosquito when a newspaper will do?

I'm totally with you on the gear swap though.

 

[The_Dude]

Here are my thoughts,
If you are going to mess with the rear at all, go all in.

I mostly agree with you, but the budget is a problem. I'm currently up to my ears with a 5-speed conversion in my '69 convertible. Currently the plan is, if it's just the outer bearings, I'm just replacing those. If it needs more, I'll rebuild it all with 3.55s (I drive a lot of highway miles in this car and it will never see a track).

 

[2000xp8]

I mostly agree with you, but the budget is a problem. I'm currently up to my ears with a 5-speed conversion in my '69 convertible. Currently the plan is, if it's just the outer bearings, I'm just replacing those. If it needs more, I'll rebuild it all with 3.55s (I drive a lot of highway miles in this car and it will never see a track).

Well, if the budget is the issue, i still wouldn't just do the outer bearings.
If they are shot, the others soon will be and the rear takes like $40 worth of fluid and friction modifier, so you still don't want to do it twice.

If the axles are ok (and really the should be), change all bearings, rebuild the trac loc and change the gears. IMO you have to rebuild the traction loc, it would be ignorant to not do it while the rear is open, you will hate yourself if you got it back together with new fluid and it started the one wheel peel.
For the record, there is no mileage difference in 3.55's to 3.73's.

 

[2000xp8]

While I agree that would be a stout rear end set up, 31-spline axles are pretty overkill for most applications. The 28-spline units will hold up fine through most power levels. Only when he really starts hooking up is he going to need something more "robust". If the guy hardly ever see's the track and is making under 300hp he's probably never going to have an issue with the stock axles. Even with Drag Radials. The stock trac-loc with upgraded disks is probably fine too. No sense using a hammer to swat a mosquito when a newspaper will do?

I'm totally with you on the gear swap though.

With you on that gear, my only thought is that 03/04 cobra traction loc's can be had pretty cheap with shopping and they are 31 spline, so if he had to buy axles might as well just get the cobra locker and 31 spline axles.

 

[Mustang5L5]

$400 axles? Are they made of gold?

Moser axles are $250
http://www.latemodelrestoration.com/item/MOS-7993-28/79-93-Mustang-28-Spline-4Lug-Moser-Rear-Axles

Outer bearings and seals are $30
http://www.latemodelrestoration.com/item/AK-1563K/1979-04-Mustang-Rear-Axle-Bearing-And-Seal-Kit

The job is easy to do. Just need to rent a slide hammer from autozone and a bearing puller.

You won't even know if the axles are bad until you pull them, and even then you can go get a repair sleeve bearing at an auto parts store.

There are inner bearings as well, but if your rear end needs a rebuild, you can do this job with the install of new clutch disks and new gears.

Either way, if the shop wants to charge you $1000 to rebuild a rear end...well just order this

http://www.summitracing.com/parts/FMS-M4001SVT373/

 

[The_Dude]

Either way, if the shop wants to charge you $1000 to rebuild a rear end...well just order this

http://www.summitracing.com/parts/FMS-M4001SVT373/

They wanted $600, but that was without axles. I was searching for that rear end yesterday. I remember Ford Racing selling that rear for like $800, but that was 5 or 6 years ago.

Edit: I did find that one yesterday. It's for '05 and up. What needs to be done to make it fit a '91?

 

[Mustang5L5]

They might still sell the 79-98 rear. Injust did a quick google search and thought that was it. Different part number


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[Mustang5L5]

Either way $600 to replace bearings only is excessive.


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[The_Dude]

They might still sell the 79-98 rear. Injust did a quick google search and thought that was it. Different part number


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As far as I can tell, no one sells the complete assembly anymore. You have to rebuild your old one.

 

[The_Dude]

I had another guy look at it, (who I know I can trust), and it does need outer bearings and the axles are bad. He said the rest was in great shape. Against popular opinion, I'm going the cheap route with axle savers and outer bearings. This car only gets driven in the summer. The engine needs a rebuild, so after I do that, I'll rebuild the diff with new gears.

 

[krazedstang]

this post is depressing.... I want to beef up my rear end while swapping to a 5 lug and 4 wheel disc brakes. It's just to darn expensive for me right now and probably the next year