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Spaceman
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350 Posts
Discussion Starter #1
Gentlemen,

Once again I'm going to seek this forum for reason and wisdom, and once again I'm certain that you fellow GT aficionados can point me in the right direction.

A couple a weeks ago I noticed a 'metallic clicking' coming from the left rear when accelerating from stand still. The 'clicking' appears when I engage first and second gear, but not in 3-4-5'th gear (Getrag 240).

I have of course tried to find out the reason, and in connection worked my way through all rear suspension parts, exhaust, brackets, rubber rings, bushings, etc., without getting any closer to what is causing the clicking. To be honest, at that point I thought it was something very simple.

Then during the annual Oil of Man rally, Sunday 20'th August, (Gentleman style & driving) a new and more worrying sound appeared. Now a nasty clonking and rattling sound from the right rear appears when starting from stand still and accelerating through especially first and a little in second gear, and a little more clearly if I'm turning (left or right).

Both sounds disappears when I reach normal road speed (between 50 - 130 km/h). The differential has been humming since I got the car 3 years ago, but the sound has not evolved and has never been in a level where I could not live with it...- but I knew it was a sign of wear & tear.

I can provoke the left rear clicking sound to appear in 3 & 4 gear if I lift and then very quickly tap the accelerator pedal, but I can't provoke the clonking and rattling sound from the right rear once I reach normal speed.

If I accelerate really really slow from stand still, nearly only the left rear clicking sound appears, and only in first gear. Diff & gearbox oil is pretty fresh and gearbox changes smoothly in all gears up & down.

When up in speed (eg. 60 km/h) I can press the pedal and accelerate pretty hard, without anything, apart from the diff. humming sounding a little louder.

I guess the above is all rear axle related, and a easy fix (if such) would probably be changing the complete rear axle, but the diff and bearings in a used one could easily be worn as well.

Advice's are welcome (as usual, I might add).

I managed to drive through the hole Oil of Man rally and home with the car one piece, by the way !
 

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Über Genius
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9,254 Posts
You just described the symptoms of bad wheel bearings.
Is there any lubricant in your differential at all?
 

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Opeler
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844 Posts
Rear wheel bearings are greased and sealed. If you look on the brake backing plates from under the car, is there any sign of differential lube coming out? That usually indicates a wheel bearing going bad to the point where the seal no longer prevents this leak.

I would try adjusting the rear brakes and see if anything changes.

You might also check the axial play on both axles.
 

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Registered
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712 Posts
I don't wish to be a fear-monger and I cannot say that I have enough recent experience with the various noises that can develop at the back end, but I will say that it does sound like an axle bearing, although, years ago my 1970 GT chipped a tooth on the ring gear. The chip managed to get wedged between two teeth on the gear and the result was considerable vibration at low speeds that seemed to improve as the speed moved higher. You would have to remove the differential cover to find this, which would mean that you would get to replace the oil again. My personal preference would be that it is a bad bearing. Hope you find the cause and that it is quickly, easily and cheaply repairable (specially cheaply).
 

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Member
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1,183 Posts
Rear wheel bearings are greased and sealed. If you look on the brake backing plates from under the car, is there any sign of differential lube coming out? That usually indicates a wheel bearing going bad to the point where the seal no longer prevents this leak.

I would try adjusting the rear brakes and see if anything changes.

You might also check the axial play on both axles.
It depends on the year. Early rear axle bearings are lubed from the differential oil.
 

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Opeler
Joined
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1,463 Posts
The clicking sound is the exact same symptom that my '73 exhibited when my pinion bearing went out. I could hear it better with the drivers window down while driving next to a curb, which I guess amplified the sound. Replaced the pinion bearing and problem solved!

Upon teardown, the pinion bearing race was found to have suffered serious surface metal failure via the spalling process. The surface of the race had released many small pieces of metal, but the bearing rollers were relatively unharmed.
 

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Spaceman
Joined
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350 Posts
Discussion Starter #10
@Dmcbrass,

My GT is a 1971, chassis nr..2426105, so it should be with the sealed bearings.

The distinct pleasure of fiddling with the rear bearings and differential is unknown territory for me, but with my luck it'll probably be a real PITA.

I can get the axle bearings from Splendid.Parts, and I guess I can handle those my self. When it comes to the ring and pinion gear I better leave it to the professionals.

Thanks so far.
 

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Spaceman
Joined
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350 Posts
Discussion Starter #12
Norbert,

My best friend from Bremen DE. You have helped me out so many times it's getting a little embarrassing, and I can't thank you enough !!

Rocker Arms & Pivot Balls, tricks for engine rebuild and tips for changing the blue 20 teeth pinion gear. You deserve a 'manly man hug', and beers on me should you ever travel the 440 km to Copenhagen DK.

Can a broken return spring really make such noise accelerating from stand still and then disappear within speed between 40 - 130 km/h ?

I'm going to take a closer look at it tonight.

If it turns out to be more severe than a return spring would you suggest to find parts for a rear axle rebuild or try to hunt down a complete replacement ? I guess the rear axle bearings are fairly easy to replace..- ring & pinion is way beyond my skills.

Best of wishes.

Anders.
 

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Senior Contributor
Joined
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5,023 Posts
@Dmcbrass,

My GT is a 1971, chassis nr..2426105, so it should be with the sealed bearings.

The distinct pleasure of fiddling with the rear bearings and differential is unknown territory for me, but with my luck it'll probably be a real PITA.

I can get the axle bearings from Splendid.Parts, and I guess I can handle those my self. When it comes to the ring and pinion gear I better leave it to the professionals.

Thanks so far.
Axle bearings are unfortunately not easy to replace without a press or special tool to remove them and then press them back on, including the bearing retainer ring which is not reusable. Also remember to buy axle bearing gaskets.
 

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Spaceman
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350 Posts
Discussion Starter #14
Jeff,

Bloddy Nora & freekin hexx ! I see what you mean, and I can defiantly say I don't recall having access to a press of that kind...

This seams more & more as a job I just have to leave with somebody who has the tools, the qualifications and experience. For now I'll just pray that it's a return spring or something simple, though I doubt it.

Anders
 

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Opeler
Joined
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844 Posts
Axle bearings are unfortunately not easy to replace without a press or special tool to remove them and then press them back on, including the bearing retainer ring which is not reusable. Also remember to buy axle bearing gaskets.
Special removal tool = chisel & hammer per FSM. When I did it, one or two blows was enough to expand the ring and it just slid off (not even split).

It's been a while, but I believe I just put the axle (inverted) in the shop press with semicircular press plate holes around the axle. What I thought was going to be difficult turned out to be a piece of cake.

Bill
 

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Senior Contributor
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5,023 Posts
Special removal tool = chisel & hammer per FSM. When I did it, one or two blows was enough to expand the ring and it just slid off (not even split).

It's been a while, but I believe I just put the axle (inverted) in the shop press with semicircular press plate holes around the axle. What I thought was going to be difficult turned out to be a piece of cake.

Bill
Yes the ring is the easy part to get off, the bearings are another story to pull off unless you have a tall press and the proper support pieces to put under the bearing otherwise you will destroy the sheet metal retainer piece. Installing the bearings and the retainers also requires a tall press. I only showed half of the special tools that I made to do the job. There is a puller that I made to remove the bearings which is just as tall as the press frame that I made. I didn't say it was impossible I just said it was not easy.
 

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Member
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1,183 Posts
SInce this is the later style bearing, the axle thrust is carried in the wheel bearing. If the wheel bearing is going bad you should hear a change in sound when turning, swirling side to side. You also should hear noise when coasting. This doesn't sound like a wheel bearing failure. Pull the drums and check the brake hardware. A howling sound when accelerating is often caused by too much pinion to ring gear backlash, caused by worn carrier bearings. While it's an annoying sound it rarely leads to a total failure. If you don't find a problem with the brakes, it's time to pull the differential cover for an inspection.
 

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Spaceman
Joined
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350 Posts
Discussion Starter #18
Jeff & Bill,

The goddess of Fortune hasn't been on my side so far, but one of the Jap-dudes (drives a Nissan Skyline) in the workshop does have a press for axle bearings.. so far so good.

I'm going to take a closer look later today.

Thanks for support and advice's.

Cheers
 

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Opeler
Joined
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844 Posts
Yes the ring is the easy part to get off, the bearings are another story to pull off unless you have a tall press and the proper support pieces to put under the bearing otherwise you will destroy the sheet metal retainer piece.
Jeff,

Maybe your're correct, but I don't remember fighting with the bearing itself on my axle. I probably used a split bearing puller. I'm sure care is needed not to damage other things.

Bill
 

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Resident Whippersnapper
Joined
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1,220 Posts
I used a hammer, a punch, a chisel, and an angle grinder to remove the bearing and retainer. I carefully cut into the retainer with the grinder, then split it open with the hammer and chisel. The bearing though, is hardened steel, and can fracture and send metal chips flying. So naturally, I used the grinder and chisel to remove it too.

Remember, do as I say, not as I do.
 
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