Rear wheel bump steer due to worn rear bearings?

[84FLH]

Hey everyone;

VEHICLE STATS
2000 Mountaineer. 301,190 miles. Good shape for the miles. New Monroe SensaTrack shock all around with about 10,000 miles on them.

SYMPTOMS
1. Subtle but noticeable wander at highway speeds. Moderate or heavy cross winds really push vehicle around, to point of being scary.
2. When rear tires go over good sized bump, rear end bumps pretty hard to right side (mostly seems to right side).

ACTIONS TAKEN SO FAR
1. Jacked rear end up, tried to move both tires side-to-side. No movement at all in driver's rear tire. About 1/16" to 1/8" side-to-side movement in passenger rear tire.

QUESTION
1. Does the 1/16" to 1/8" side-to-side movement indicate worn bearing?

THESE THREADS SEEM TO INDICATE WORN BEARING, ANYONE CONCUR?
http://www.explorerforum.com/forums/showthread.php?t=312249
http://www.explorerforum.com/forums/showthread.php?t=276246

CAN ANYONE TELL ME APPROX DEALER PRICE TO REPAIR?
1. It's my only vehicle and I've no garage to do the job in.
2. Plus, I moved to my location only one month ago and don't know which shops are reliable and which aren't.

**********************************************************

Thanks everyone. This site and the knowledge base of people here are each invaluable.

 

[Aussiefnq]

Any movement in and out? Sometimes a broken leaf spring centre bolt can cause havoc to the rear end when driving, although you shouldn't have any noticeable movement at all when you grab your wheel, usually a worn bearing will be heard before it is felt, although that is not always the case and I've known people to lose their axles and wheel assembly on the road before they knew the bearing was faulty, I myself had one seize up when I was a teenager, out the middle of no-where in an old Falcon, so I would be pulling sides both out and replacing if it was me

 

[Flash]

Those symptoms sound more like worn leaf spring hanger bushes.

Because the rear axles are held in by a C clip not a flange, there can be a fair bit of lateral movement. Scared me when I first saw it. Can't be good for brake pad knock off.

You should also look at your shocks including the 5th one as well as the sway bar link and mounting bushes.

How's the air in the tyres?

 

[84FLH]

Any movement in and out? Sometimes a broken leaf spring centre bolt can cause havoc to the rear end when driving, although you shouldn't have any noticeable movement at all when you grab your wheel, usually a worn bearing will be heard before it is felt, although that is not always the case and I've known people to lose their axles and wheel assembly on the road before they knew the bearing was faulty, I myself had one seize up when I was a teenager, out the middle of no-where in an old Falcon, so I would be pulling sides both out and replacing if it was me

Yes, some in/out movement, maybe 1/4" max. I was astounded at this. Tire guy at Firestone told me this was normal for Mountaineer/Explorer.

Don't hear any bearing or similar noise.

What do you mean by "leaf spring center bolt"?

Springs are worn but still have some arch in them.

 

[84FLH]

Those symptoms sound more like worn leaf spring hanger bushes.

Because the rear axles are held in by a C clip not a flange, there can be a fair bit of lateral movement. Scared me when I first saw it. Can't be good for brake pad knock off.

You should also look at your shocks including the 5th one as well as the sway bar link and mounting bushes.

How's the air in the tyres?

Hey Flash,

Air in tires is correct all 'round.

Had Firestone replace both rear spring hangers about 11 months ago. Hangers included new bushings. Driving out the old bushings took mechanic quite some time. Maybe he buggered up bushing holes in the frame. I'll give a visual and report back here.

Now I'm not sure I had the rear end bump steer before the bushings were replaced...or a bad repair job gave it to me! This is why I hate having someone else work on my vehicle.

The 5th shock is shot. Badly. Thought that was to counter drive line lash. Could worn shock be sole source of the trouble?

Put 4 new Monroe SensaTracks on about 11 months ago. These shocks ride very harsh, though, compared to the OEM Ford's I always used prior.

What about the 1/16" to 1/8" side-to-side movement of rear pass tire? Does that indicate bearing wear?

 

[masospaghetti]

I doubt a worn 5th shock would cause the symptoms you describe, although it might contribute.

How are the leaf spring bushings?

 

[Flash]

Air in tires is correct all 'round.

Depends on what you mean by "correct". I was speaking to someone recently who thought 30psi was good for his 275x30x19 tyres.

Had Firestone replace both rear spring hangers about 11 months ago. Hangers included new bushings. Driving out the old bushings took mechanic quite some time. Maybe he buggered up bushing holes in the frame. I'll give a visual and report back here.

I was thinking more the front spring eye bushes.

The 5th shock is shot. Badly. Thought that was to counter drive line lash. Could worn shock be sole source of the trouble?

It's to counter lateral movement.
Some people say they notice no difference with or without that damper others say it makes all the difference.
I haven't tried it myself.

What about the 1/16" to 1/8" side-to-side movement of rear pass tire? Does that indicate bearing wear?

No, if a bearing was that shot you'd hear it.
That movement is because of the way the axles are retained. Like the guy said, it's normal.

 

[Aussiefnq]

Yes, some in/out movement, maybe 1/4" max. I was astounded at this. Tire guy at Firestone told me this was normal for Mountaineer/Explorer.

Don't hear any bearing or similar noise.

What do you mean by "leaf spring center bolt"?

Springs are worn but still have some arch in them.

The retention bolt or pin that keeps your leaves together. American's might have a 'local' name for it

 

[84FLH]

I doubt a worn 5th shock would cause the symptoms you describe, although it might contribute.

Tend to agree. As someone below noted, that shock is to counter lateral drive line force.

How are the leaf spring bushings?

Had Firestone replace rear shackles one year ago (Feb 2015). That included new bushings. Now, I didn't look over the guy's shoulder as he put 'em in, but I know he had a devil of a time getting the old ones out (they had 290,000 miles on 'em). He could've buggered up the bushings but I can't tell because the bushing's hidden by the shackle ends.

I'm thinking it's just a combination of worn parts after 301,000 miles.

Lateral axle movement (jack rear up, grab a rear tire at 3 o'clock and 9 o'clock, and push/pull) seems like a lot. Didn't measure it unfortunately, but had to be 1/4". Firestone tech said that's "normal". I dunno about that....

.....seems like 1/4" is enough to induce rear end bump steer over big enough bumps.

Do you know spec for lateral movement?

 

[84FLH]

The retention bolt or pin that keeps your leaves together. American's might have a 'local' name for it

Got it. Thank you.

 

[84FLH]

Depends on what you mean by "correct". I was speaking to someone recently who thought 30psi was good for his 275x30x19 tyres.

Had tires rotated and air checked yesterday by Firestone. 50,000 mile guarantee and this is second 5,000 mile rotation. Air pressure correct.

I was thinking more the front spring eye bushes.

Ahhh. How would loose/worn bushing allow/facilitate rear end bump steer?

A visual inspection found the front eye mounting gussets/brackets have heavy surface rust but are otherwise solid. Same for front of springs. Bolt heads look good, though.

Any way to check bushings w/out removing the bolts?

That movement is because of the way the axles are retained. Like the guy said, it's normal.

I think you're mistaking what I was trying to describe. I was talking about side-to-side tire "wiggle" as opposed to end-to-end axle lateral movement.

With rear tires off the ground, I grabbed drivers and then passenger rear tires at 3 o'clock and 9 o'clock and tried to wiggle them, left to right, as hard as my overweight 200 lbs could.

Drivers side rear tire didn't budge. Passenger tire moved ("wiggled back and forth") about 1/16". From what I glean on the forum, there should be no movement whatsoever, and that means the 1/16" movement would indicate worn bushing. Would that be a correct statement?

I think you're talking about what I'll call here "end-to-end axle play". With rear tires still in air, I grabbed a tire (pass or driver side) and tried to push/pull it towards the opposite side of the vehicle. I got, best I can remember, about an astonishing 1/4" end-to-end movement.

Firestone tech said that was normal. Now that I think about it, I have a hard time believing 1/4" is acceptable end to end axle play. The play should be only as much as the width of the circlip groove, minus the thickness of the clip, no?

Do you know rear axle lateral movement spec?

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Thanks, Flash. Always glad to have you answer.

 

[84FLH]

More on rear axle end play....

http://www.f150online.com/forums/other-powertrain/374839-rearend-axle-end-play.html

The OP complained of a clunk from rear end when going slowly over bumps. He measured .030" end play in his F150 8.8 LS rear end. He asked what end to end spec was. No one knew (at first). Others went on to say .030 end play wasn't much at all. Some said they had up to 1/8" end play. Others said worn clutches in diff can cause excessive end play in F150 8.8 LS rear end, and that Ford sold clutch shim kits.

Finally, one poster said Ford end play spec was .030" exactly for 8.8 LS diff.

Will have to check my end play again. If it's very excessive that might be cause of my rear tire bump steer.

Always learning something here.

 

[84FLH]

1930's vid: how rear diff works...

https://www.youtube.com/watch?v=K4JhruinbWc

Probably baby stuff to the experts here but I found it well made and very informative; starting with basic problem of different rates of speed for tires moving in arc (corner, turning, etc).

 

[Flash]

Ahhh. How would loose/worn bushing allow/facilitate rear end bump steer?

If there's front to back movement of the leaf spring due to worn spring mounting bushes then the rear axle can steer like a cart.

A visual inspection found the front eye mounting gussets/brackets have heavy surface rust but are otherwise solid. Same for front of springs. Bolt heads look good, though.

Any way to check bushings w/out removing the bolts?

Don't know. It only happened on one of my cars and it showed up on a 4 wheel alignment.

I think you're mistaking what I was trying to describe. I was talking about side-to-side tire "wiggle" as opposed to end-to-end axle lateral movement.

With rear tires off the ground, I grabbed drivers and then passenger rear tires at 3 o'clock and 9 o'clock and tried to wiggle them, left to right, as hard as my overweight 200 lbs could.

Drivers side rear tire didn't budge. Passenger tire moved ("wiggled back and forth") about 1/16". From what I glean on the forum, there should be no movement whatsoever, and that means the 1/16" movement would indicate worn bushing. Would that be a correct statement?

Yes, it would. The only play should be toward you as if you're pulling the wheel off.



Do you know rear axle lateral movement spec?

No, I don't, sorry. IMO, it's too much.

 

[84FLH]

Thank you Flash...

Most of all for the answer re: 1/16" bearing movement passenger rear wheel. Few months ago I read on this forum there should be absolutely no bearing movement. It's easy to dismiss the tiny amount I found as nothing. The reality is it'll only get worse with time.

 

[masospaghetti]

Probably worth changing that axle bearing, sounds like its shot - even if its not causing your swaying problem, it needs to be replaced.

Check the axle when you remove it to see if the axle surface is worn down. If it is, they make "helper" or "axle repair" bearings that will prevent you from having to buy a whole new axle.

 

[84FLH]

Probably worth changing that axle bearing, sounds like its shot - even if its not causing your swaying problem, it needs to be replaced.

Check the axle when you remove it to see if the axle surface is worn down. If it is, they make "helper" or "axle repair" bearings that will prevent you from having to buy a whole new axle.

Thank you. I agree. Found excellent DIY thread here:
http://www.explorerforum.com/forums/showthread.php?t=214805

Question. Do the the bearings in the helper bearings have same amount of contact area with axle bearing surface as standard bearings have? Just curious.

 

[intelisevil]

Thank you. I agree. Found excellent DIY thread here:
http://www.explorerforum.com/forums/showthread.php?t=214805

Question. Do the the bearings in the helper bearings have same amount of contact area with axle bearing surface as standard bearings have? Just curious.

Yes the bearing contact surface is wider than stock, more importantly it moves the bearing surface to a previously unused area on the axle. If your axle is already showing signs of wear from the original bearing, this "axle repair bearing" will allow you to use your old axle!

Here's the axle bearing I used, I replaced both sides at once even though only one side was worn and leaking. It's a one piece unit, not seperate bearing and seal: https://www.napaonline.com/napa/en/p/BRGR1559_0074208450

When I replaced mine last year I also used Gavin's excellent write up. I thought I was just replacing my brakes all around until I got to the passenger rear and found oil leaking. I found that I could move my axle up and down about 1/8", even worse than yours.

I'll admit I just saw $$$ signs when I found the oil leak. After reading Gavin's write up the first time I kind of freaked out, I had never seen the inside of a differential in person before . . . I read it (and others) SEVERAL more times and convinced my self I (a 57 year old couch potato) could do it.

Basic hand tools handled most of the work, the few specialty tools were "rented" from AutoZone's Loan-A-Tool program. Buy them up front and return for 100% refund.

My cross pin bolt was already broken when I opened up the differential (post 185 in Gavin's thread). Buy one before you get started. Also buy this kit: http://www.fabbriassociates.com/kitinfo.html You might not need it but if you do, it's worth it's weight in gold!

I also replaced the c-clips that hold the axles in. One of them was worn and that axle moved in and out about 1/4".

I read many stories about what sealant works and what doesn't with gear oil. I ended up buying this reusable gasket: http://www.amazon.com/Lube-Locker-Ford-Differential-Gasket/dp/B008RAFJ38

I wish I would have replaced the differential cover at the same time but I did at least give the stock one a light sanding and a few coats of rattle can Rust-Oleum Black paint.

I did mine over the period of about a week after getting off work. I was working on a well packed gravel driveway, at least it wasn't raining.

10 months and 12,000 miles later, no leaks, no strange noises and hundreds of $$$ still in my bank account!!!

Good Luck,