Anoehr Bent Axle and Rear Wheel Vibration

kontoboy · #1 (**permalink**) 06-27-2009, 12:50 PM

I have a 2wd 3.0L '95 Aerostar with 109K on it. Every since I bought it it had a mild vibration in the right rear at spped. New tires, new drum, new steelie wheel wouldnt make it go away, but it was mild and tolerable up until about 10K ago when it got progressively worse with the right rear brake getting grabby and the emergency brake adjuster tightening up.

I pulled the axle and put it on my motorcycle wheel balancer and could see the shaft was bent on the inboard side. I replaced the axle and saw some wear on the differential so I replaced that too with a 7.5 limited slip. Wheel bearings seemed OK--no slop and tight fit on te replacement axle so I left those is place. Rear brake cylinder seemed to leak some some so I replaced that also and bled the system.

All was good for about 1000 miles and then the vibration started coming back. I suspect the rear axle might be bent again but how?

With two kids in school I need to keep this for awhile but I'm kind of tired just throwing time and parts into the back end. (I'm putting in a rack and pinion this weekend!).

Any suggestions?

Thanks

Kontoboy

Torsen Rick · #2 (**permalink**) 06-27-2009, 01:23 PM

I would guess that if axle shafts are being bent, then I would agree that you need to look beyond the shaft itself - the axle housing that they run in is also bent. That's my bet, too, of what is the source of the problem. How that got bent is another issue, though.

I've been working with axles for quite a while and can say that even the smallish 7.5" axle housing doesn't bend for no apparent reason. I could see it off-road, maybe, in an aggressive situation (off-road racing bends axles), but not in normal street use. The 7.5" and the larger 28-spline 8.8" axle share common tubes, axle shafts, backing plates, bearings, etc. So if anything, those areas are overdesigned for the 7.5" axle.

What history do you have for it? Was the van in an accident? Tied down to trailer or roll-back improperly? Maybe hit a Geo-swallowing pothole? Or maybe someone played Dukes of Hazzard with it? Because if that axle tube is bent, it required some force to do it.

xlt4wd90 · #3 (**permalink**) 06-27-2009, 01:30 PM

Maybe your axle housing is bent? Axles usually get bent from hitting curbs. This can also damage the bearings. Overloading will also wear out the bearings.

You actually replaced the differential assembly? Did you set up the gears as well? That's a lot more than most of us here can do.

kontoboy · #4 (**permalink**) 06-27-2009, 04:42 PM

I bought the van with 32K on it, and as mentioned at the time it had a minor vibration. It's been in no accidents since I've owned it, and I don't recall any hard curb hits, but I do use it as a work horse hauling lumber, wallboard, tile and such so it has seen some very heavy loads. I also lend it out to friends haul mulch, take kids to college and such--one friend drove it from Northern VA to Sante Fe, NM and towed a car back with it.

Given the abuse it's seen, a bent axle housing seems very possible. I've eyeballed it for a bend but can't really tell. Any way to easily check? (I thought about pulling the axles and differential and shine a laser through--but that isn't easy.

Sourcing an axle housing will be troublesome. Our local junk yards (Metro DC Brandywine franchise) seems to think the standard price for their used parts is half the retail price! I know they've got a least half dozen Aeros sitting there and as I recall most had their rears.

And there is eBay, but shipping on axle housing can't be cheap.

When I was shopping for a differential a guy was trying to talk me into buying a used rear end he had for $250. He was near Pittsburgh which was a 4 hour drive so I passed. I kind of regret it now.

I'll just need to start looking. At least the Aero is driveable.

When I swapped the differential I didn't index the gears. I just used that paste to check the contact patches. They were spot on and there has been no sound out of the differential. Time will tell, but I did the same thing on my son's Nissan 50+ K ago and no problems.

Thanks for all the advice.

Kontoboy

P.S. Just finisihed putting coolant hoses, serpetine belt, rack and pinion and tie rod ends in the van. That R&P is one messy job. Now I need an alignment.

rebocardo · #5 (**permalink**) 06-28-2009, 03:07 AM

I forget exactly what it was, but, there was a TSB in 1995 for rear end vibration. I forget what was replaced, but, I had it done. Might even have been a Federal recall.

rebocardo · #6 (**permalink**) 06-28-2009, 03:17 AM

I think it was 98-1-12 new center support, fixes vibration caused by rear end play.

kontoboy · #7 (**permalink**) 06-28-2009, 10:04 AM

I Googled 98-1-12 and can see there is a bulletin on a center support but can't access the bulletin itself without paying....

Googled some VA junk yards too and found some rear ends--seems they want to sell the whole rear end--not just the housing. Prices range from $150 to $500. $150 to $250 doesn't seem bad--I'm just nervous about getting and installing one and then discovering it has problems too.

Kontoboy