Differential mounting pin, dimensions advice

[David B2]

Good day,

I have just fitted the Diff to my IRS chassis having purchased and trial fitted new Rear Bridge Pin/Bracket assembly supplied by CTM. Also used new Rimmer Rubber Mounting cones. (Brackets not welded to rear bridge yet).

 

When securing the diff in place on the rear mountings, the big special securing washer does not preload the rubber mounting cones when it is tightened up to the shoulder of the pin. It leaves the diff loose on its mounting. Why ???

 

I am trying to contact CTM but no reply yet, they may be on vacation so am trying this.

 

Are there different versions of the Pin/Bracket assembly ??

 

The CTM bracket measures 60.6mm.

The rusty old bracket removed measures 59.0mm.

 

Both the new Mounting cones and the old ones measure the same. They don't seem to be the problem.

 

What should the dimension be (as attached photo) as I think the ones i have been supplied are protruding too far from the bracket and not clamping the rubbers.

Does anyone have experience of this as a problem when fitting new pins.

Thanks, David B

Edited July 27, 2018 by David Baram

[Paul J]

Hi David

Just going through a similar stage on a TR6.

The TR6 pin is 62mm and TR4A is 57mm Found this info on Revingtons site.

Regards

Paul

 

Bolt, Support bracket, Rear axle Mounting TR250, 5, 6. Rear cross member

This bolt (Pin) is supplied for the rearmost Differential support bracket for all IRS cars TR4A to TR6.
This part number is in fact the TR5, 250,6 part and is set, for these cars with 62mm of the plain portion of the bolt protruding below the bracket.

TR4A IRS cars us the same bolt in the rearmost position but with 57mm of plain portion protruding to account for the different rear mounting arrangement.


When replacing this bolt fit strengthening kit RTR7012-1

[David B2]

Paul,

Thanks for post. I've been searching high and low for info but didn't find it even on the Revington site. Will have another look as that will explain it.

 

Thanks, David B

[Paul J]

David

The TR6 Diff has a different rear mounting arrangement, seems CTM May have supplied you with the long TR6 pins. Not sure if a thick compensating washer would be ok though.

Paul

[Z320]

59.5 mm,

measured on the old one from my scrap box,

pulled out by the diff last year from bridge and lower bracket on my TR4A

[AlanG]

Had a similar problem when I changed the rubber cones. I doubled up the washers.

Alan.

[David B2]

Problem now solved with replacement pin/bracket assembly, to 57mm dimension, resupplied by CTM. Washer, when clamped up to the shoulder of the pin, now secures the rubbers.

Thanks Colin/Andy of CTM for prompt action to replace.

 

Thanks to all for advice of what dimension should be, particularly Paul J with Revingtons info. Note to Alan G the washer goes up to the shoulder of the pin so more washers wouldn't solve the problem.

 

Whilst having the diff out I thought i would sort out the oil leak from the nose of the diff. See new thread !!!

 

Thanks all. David B

[AlanG]

I remember now, I opened up the hole in the first washer to go over the shoulder of the pin then fitted a standard washer. Well it was a few years ago and my memory doesn't improve with age. Probably committed some cardinal sin but as I didn't remember doing it I didn't have any worries about it.

Alan ( I think )