Diff mounting bushes

[J.Lackland]

During the past year and a half I’ve found help with every problem I’ve had on my -75 2200TC
in this invaluable forum, but couldn't find any post covering this one. Help much appreciated.

I am about to replace the diff mounting bushes on my ’75 2200 starting with the rear pair.
As the original bushes aren’t available, my supplier sent me a set for the P6B.

First question:
The confusing bit is which way to put upwards – the larger section or the thinner, tapered one?
Strangely enough the best fit was had with the larger section downwards– but can this be right?
In the pictures the old bush is on the left.
The first one shows the way I hope it is to be fitted :roll: .

The second pic’ shows the new bush turned downwards, the way it sat when I got the “best fit”
as mentioned above :?


Second question:
The Haynes manual doesn’t mention torque settings for these bushes, does anyone know the values
for the centre support nut/bolt and the two nuts/bolts securing the bush to the body?

Cheers // Johan

 

[SydneyRoverP6B]

Hi Johan,

I have only recently learnt that there were variations in the bushes fitted to the 2000 models, so my assistance is going to be someone limited. In the case of the 3500, the correct orientation is how they appear in your first photo, ie the larger section facing upwards. The torque for the main centre bolt is 45lbs/ft, the two smaller bolts that locate the mount to the base unit, 17lbs/ft.

Sorry I can't be more help, but I know that Dave3066 has a 2000, so hopefully he'll see your post and drop by with lots more help.

Ron.

 

[J.Lackland]

Hi Ron!
Feels good to get a reply this quickly. Will wind up for the day and start afresh tomorrow afternoon.
I have a hunch that the reason the bush fit so well downwards might have been that the diff had sunk
slightly due to the cracked old one, thus increasing the space between the fixing point in the body
and the distance piece on top of the diff bracket.
Johan

 

[vaultsman]

Hi Johan,

2 scans from the 2200 Parts Catalogue...




I don't have a 2200 factory Workshop Manual, but the 2000 WM makes no mention of the bush flange-to-body tightening torque.



Good luck...hope this helps!

Stan

 

[pat180269]

I have just done this job.

The bush on the left ( old one first pic ) was only fitted to later cars and is not available now. The one on the right looks similar but not the same as the ones I have just fitted from J R Wadhams. As already mentioned the correct orientation is in the first picture. The mounts are fitted from the boot with the large rubber part facing upwards. I replaced the small bolts which hold the bush in place; used M8 BZP High Tensile bolts ( HT are marked 8.8 on the head ) and M8 nylocs. ( available from screwfix!)

The replacement bushes I got were smaller in diameter and thickness. Wadhams supply the same bush for both diff bushes and the pinion extension/crossmember bush. Because of the reduced thickness it is necessary to make up spacers above and below the bush so that when everything is re-assembled it all sits at the same height as before. I hacked out the metal tube from one of the old bushes and cut this to the required height. In my case it was 7mm above the bush and 10mm below.

Pat

 

[J.Lackland]

Yes! The rear ones are on now and it's time to enjoy some rest before the sun sets.

Stan, your scans were invaluable, they made me realise I must fork out for copies of the parts catalogue
and workshop manual - the only drawback will be seeing the time allowed for a job and feeling small -
I have spent considerable more than 1.9 hrs on this job

Pat, I got my bushes from WINS. When measuring them (after the initial confusion), the distance
between the mounting plate and the bottom of the bush at the tapered end, was found to be
identical to the old one. Thus the bush meets the steel sleeve on top of the mounting bracket
at exactly the same level as with the old bush should do if it was OK. Absolutely not my old bushes, as they
both have split, thus allowing the diff to move about. (When I first tried to fit the new bush upside-down,
the distance between body and bracket was about 5/8" more than with the old bush).
Thanks for the info on bolt standards, my country went metric ages ago and very, very few shops stock UNF/UNC.
Well, in my youth we at least used inches for sawmill products. I can't ever visualize a 95mm plank, but a 4" one makes sense.

Next stage will be to remove the diff front mounting in order to get going with the job that triggered all this:
replacing the diff extension bearing, as I have rumbling noise from that area when on the move. I HOPE my diagnosis
is correct as there is a small oil leak as well as a slight play, but you never now. I'll certainly come back for help if, sorry when
I stumble on something. Cheers // Johan

 

[colnerov]

Hi, your 'rumbling' noise may be the prop shaft bolts clipping the cross member due
to the diff mount being soft and collapsed a little. So change the mount, then test
drive before going into the bearing.

Colin

 

[harveyp6]

Hi, your 'rumbling' noise may be the prop shaft bolts clipping the cross member due
to the diff mount being soft and collapsed a little. So change the mount, then test
drive before going into the bearing.

^^^WHS^^^

I can't ever remember changing a pinion bearing because it was noisy. Plenty of collapsed mountings though. The way the pinion seals leak there's obviously a good oil supply for the bearing, which is probably why they don't give problems.

 

[J.Lackland]

Colin and Harvey!
You're quite right re the bearing. Having removed the extension, I can't find anything wrong with it,
but will replace it all the same. After dismantling the soggy mass that once was the front mounting,
(even when cleaned it's squishy like something the dog's dug up) I decided to the at least change
the oil seal, which probably leaks while on the move (no visible leaks when parked but there's less oil
than it should be).
Can't find any signs of chafing which is a bit of a mystery.
Will come back when finished and report on the result.
Cheers // Johan

 

[J.Lackland]

Final report:
After a round trip of roughly 100 kilometers it transpired, as foretold by some, that the noise didn't come from the extension bearing.
The good thing is that it is much less noticable at speed which seems reasonable as the diff unit doesn't move about any longer.
Also, before the repair the whole transmission unit shook when passing bumps, potholes etcetera, but this fault is now gone.
The car seems softer at the front end though but, again, this is to be expected as the rear has been stiffened up.
Will try to enjoy car for the rest of summer before making further repairs.
Picture below from a local meet today with 400 cars attending where this car, as sole P6 in attendance, was chosen for special presentation

Thank's all for your help!
Keep the flag frying!

 

[chrisyork]

well done!

And I bet a Paprika colour brings a bit of cheer to those long winter nights! We like Paprika!

Chris