New 122S owner troubles - vibration in reverse
 

I purchased a 66' 122S in October last year and so far, I've yet to take it out on a run.

During transportation the paint was contaminated with hydraulic fluid which led to it being at a paint shop for months.

Anyway, upon driving it back I reversed into my drive and there was a vibration from the rear right wheel.

Thinking it was brakes, both sides were replaced, shoes, drums and fittings.

The noise/vibration persists but only in reverse under load, freewheel is fine.

I'm at a loss to where to investigate next.


I hope it's okay to post a link to a video of the noise/vibration?

https://www.instagram.com/p/ChFX-BuIUTM/

Any advice is appreciated.

Axle support strap rubbing in the tyre. Loosen bottom clamp and give it a bit of a twist. If you have lowered the car a bit the strap is now too long and can take a different curve. With your new wider steels you have also fitted wider tyres. 195/65/15. This can also put the inside of the tyre closer to the strap.

Hi, upon further investigation when spinning the rear right wheel backwards the prop shaft fails to turn.
Spin the wheel forwards the prop shaft turns as it should.

No issues with the rear left wheel either forwards or backwards.

I'm guessing that it's a diff issue?

(I did take a look at the strap and it doesn't foul the wheel/tyre)

Noise
 

I realise the prop turns OK both ways from the left wheel.
Before going for the axle, remove the rear prop shaft flange from the axle and do the same tests. It could be the prop universal joints where the roller bearings are " biting in" and attempting to jump over each other. If the axle test is normal, completely remove the prop and check all x4 joints plus the centre bearing.
The prop is much easier and cheaper to fix than the rear axle.

Thank you I shall get back under tomorrow and try that.

This is confusing.

Are both rear wheels up in the air? On a normal open differential if you spin the right wheel backwards the left wheel would turn in the opposite direction because of drag in the transmission. If you can spin the right wheel backwards and the prop shaft does not turn and the left rear wheel does not turn forward you would have an exceedingly unusual differential problem, one that I expect would be accompanied by an awful lot of noise going either forward or backwards.

Do you have a limited slip differential by any chance? That would be exceedingly rare. The tag on the differential may indicate limited slip; but, if it was a later refit there may be no external evidence that it is an LSD. LSDs can make some interesting noises when reversing. Does the noise also occur if you make continuous sharp turns that requires lots of 'differential' action (donuts in the parking lot) ?

If you can turn the right wheel backwards and neither the left wheel or the prop shaft turns, then I think you need to remove the differential cover to figure out what is broken if you have a conventional open differential. That would also reveal whether an LSD has been fitted in which case you may have some clutch issues or the incorrect lubricant. As a first step you could drain the differential fluid and see whether any metal pieces come out.

Apologies.

When driving forward, no noise/juddering.
Reverse noise/juddering from the rear right corner.

The tyre nor wheel are rubbing.

With both wheels off the ground, reverse gear, both wheels spin equally, no noise/juddering.

When rotating the left wheel forward the propshaft turns as expected and right wheel turns opposite direction, but doesn't match the rotation and comes to a stop.
Rotating the left backwards the prop and right wheel rotate forwards.

Rotating the right wheel forward, left wheel rotates backwards and prop rotates.

Now, rotate the right wheels backwards, both the left wheel and propshaft fail to rotate.

The car's history is murky, fitted with a later B20B and M41 and aircon.
The diff does have a tag but I cannot make out what is stamped on it, so I'm not sure if has an LSD, but I don't think it does.

Clutch wise there doesn't seem to be any issues under load pulling away, I haven't noticed any noise when turning, but I will take it out for donuts tomorrow.

This is my first experience of an Amazon.

Thank you for your assistance, as I'm at a loss.

Whatever it is it sounds like something that speeds up and slows down in an engine braking kind way if that makes sense,

That should rule out prop balance, UJ's and even the diff itself, I wonder if the sound is travelling from elsewhere, it does also sound like a friction rub very much like as if the arch was catching the tyre,

With it on the floor examine for any fouling of the inner wall of the tyres both sides, probably best to drive over a phone camera placed so it won't end up under the wheel but able to catch the 6 inches of motion, I would also do the same under the gearbox as a lay-shaft bearing might be worn and the sound of it travelling,

Notice as you rev the sound speeds up and then drops off like a free wheeling bearing when you get off the pedal,

It's almost as if the shoes are rubbing the drum rather than stopping the drum, it's not that btw as you don't move far enough to create the spin,

Any movement of the wheel? Take the wheel off and try again with the rotating. Check the hub nut. Many years ago I sheared the key on the drive shaft taper on my Jeep, maybe you have the same.

I've checked the tyre inner wall, wheel, axle strap and wheels arch, all are free from mark's.

When revs are applied and clutch let out the judder occurs at the right rear wheel.

Strange.