Bent rear axle? - Vibration >90kph

[CrUZida]

I've got a vibration issue and I think I've narrowed it down to a bent rear axle flange.

When I got the GS130 wagon, she had a vibration in the whole car (fairly serious vibration) at any speed above about 90kph.
From memory I had all the wheels balanced, and there were no issues, so I put it down to an out of balance tail shaft.
Since I was doing the 1UZ conversion soon I thought I'd wait until after the conversion to get it balanced.

Did the conversion, still there.
Had the tailshaft balanced, still there.

Bought some 2nd hand 17" wheels off eBay, could only use 3 of them as one was RS, so put them on with the spare 15" on rear left.
Vibration almost disappeared (down to a liveable level).
Bought a BRAND NEW wheel to replace the RS one, had it fitted yesterday, and the vibration is back with avengence.

Could it be anything besides a bent axle?
If it is, is it repairable, or am I looking at finding a replacement axle?

The GS130 runs a solid rear diff, F series, with drum brakes.

Pics


http://conceptual.net.au/~peewee1/crown/diff1.JPG
http://conceptual.net.au/~peewee1/crown/diff3.JPG
http://conceptual.net.au/~peewee1/crown/diff4.JPG

[KENut]

I know you said the tailshaft was balanced, but have you checked the universal joints?

Strange that it began vibrating worse again with the new wheel though...

[KENut]

Also, I'd suggest checking the pinion angle, it looks ok in the pictures but doesnt hurt to check.
Any signs of a gutter tap on the old wheels?
Is that single piece tailshaft?

[rodi]

as it changed when you swapped wheels the first thing i would do is try another set of rims, put it on stands and spin the wheelsup to 100 if it vibrates take the wheels of, put only the nuts on and try again, good luck

[Negative Boost]

If its the axel flange, depending on how bad it is, you could machine the face flat.

[oldcorollas]

Bought some 2nd hand 17" wheels off eBay, could only use 3 of them as one was RS, so put them on with the spare 15" on rear left.
Vibration almost disappeared (down to a liveable level).
Bought a BRAND NEW wheel to replace the RS one, had it fitted yesterday, and the vibration is back with avengence.

so the only time it has gone was with the spare 15"?

i would suggest trying the 15" again.. see if vibration goes away..

then rotate the 15" on the same axle to a different stud position...

if the rim is bent and the axle is bent, then there might b a position where the vibration is minimised.. but if it doesn't change wtih position, then that is not the correct conclusion

is the rubber on the 15 saem width/diameter?

you could always just check the runout on the flange face with a dial gauge...

[CrUZida]

Also, I'd suggest checking the pinion angle, it looks ok in the pictures but doesnt hurt to check.
Any signs of a gutter tap on the old wheels?
Is that single piece tailshaft?

What would affect the pinion angle though, everything down there is stock (assuming the bushes aren't flogged out).
No signs of damage on the old rims
Two piece shaft

as it changed when you swapped wheels the first thing i would do is try another set of rims, put it on stands and spin the wheelsup to 100 if it vibrates take the wheels of, put only the nuts on and try again, good luck

I'm putting the fact that it "disappeared" with the 15" rim down to the fact that it has much less rotating mass (205 on 15x6.5" vs 235 on 17x8").
Its almost identical vibration between the original 17's (which came with the car) and the new ones.

I do plan however though to spin it up while on jack stands to see if anything is moving.

[Cuzzo]

Hmm sounds like a doozy.

IS this the daily? If not remove the diff and get it straighten and check?
Brakes ok?

[thechuckster]

phasing of uni's in tail-shaft OK? or is a 1-piece unit?

[KENut]

What would affect the pinion angle though, everything down there is stock (assuming the bushes aren't flogged out).
No signs of damage on the old rims
Two piece shaft

Looks lower than stock? Therefore diff might be pointing up a bit
Is the tailshaft aligned properly, and the universal joints around the right way
(ie unis at 90 degrees)

[CrUZida]

Tailshaft has been fitted the same way it came back from the balancing place.
Prior to going there the front half was 90deg from where it should have been, and it didn't make a difference.

It is a daily but if it needs to come off the road to get fixed, it needs to come off.
Just looking for the best course of action when it does come off the road.
(ie, night before, remove axles, take to XYZ, get shaved, or remove whole diff, etc)

[CrUZida]

Would love to source another diff so I can just swap them over.

Any idea if its the same as something local?
Not worried about the ratio (its 4.3:1 from memory), more so the mounting points.

[Negative Boost]

The vibration with the 15's might feel less because of side wall flex taking it up presuming the side walls on the 15's are taller than the ones on the 17's.

[lexsmaz]

Hi Andrew,

As you mentioned i would be putting the car up on jack stands & running it & looking for Runout issues with the rear wheels, also you could take off the wheels & put a dial gauge on the axle flange a check for run out aswell as OC mentioned too .. Are the wheels locating properly on the centre flange on the wheel hub, as in are they going over the centre boss or catching slightly & riding up on the boss ?

As has been mentioned do the uni's rotate smoothly & no stiffness in them ?

Ideally you should have similar angle deflections at the end of each tailshaft section, ( so 4 angles in all with a 2 piece shaft but you need to treat each section on their own merit ) if one end or section has excessive angle compared to the other end it will / can cause vibration issues ..

PS, i have been pretty crook the last few days, i will be organising the bits for you Tomorrow ..

Thanks ..

Regards ..

Rob ..

[Ella]

i would also be pointing to runout in the tire and maybe even in the new wheel.

also get the balances checked, and last but not least do the wheels fit the hub correctly. or if not do they have the little rings (i have forgotten the technical term :S) that make the wheel fit properly to the weight of the car is on the centre, not on the wheel studs.