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Triumph TR6 - Differential mount pins question

Hello, I am wondering if someone out there knows (or could put a caliper on and measure for me) what the diameter dimension of the diff mount pins is supposed to be, and here is why I ask. I gave my car over last year to a "trusted" local English car mechanic to remove, checkover and redo the seals, on my diff for the princely sum of $700. Here am I a year later doing a total body-off restoration, and in taking apart the diff and axles discovered: the left side stub axle leaking fluid at the inner UJ, odd-looking supports for the rear of the diff, and most unbelievable of all, duct tape wrapped around the front pins to thicken them to fit the new mounts snugly. What kind of mechanic does this? So either the pins are undersize through DPO work, or the mechanic ordered the wrong mounts and used duct tape to get the fit better. I am assuming my pins will meet standard factory specs but just want to make sure. Oh yeah, and just to finish off the job, he left the UJ boots rolled back over themselves so as I drove away and over the next few days, the boots thrashed themselves to bits. Thanks in advance for the dims. James

H Clugston

James see comment on other thread. Large part of the pin is 9/16 in and the threaded portion is 3/8 in NSF. I suspect that the mount is defective. Seems really odd that the pin would be smaller!!
db
Doug Baker

Hi again, here is the rear mount the way it was installed - does this look right to anyone? I may be wrong but if not, why have such a large washer? JC

James Clugston

By the look of the those pics, I think you could use Dougs dif mount kit. Yes those washers were used, IIFC the original mounts that were on my car had the rubber all the way down to the washer and the washer squeezed the rubber tight.

Rob
rw loftus

Thanks Doug and Rob for your comments,
I will remove the duct tape this evening and check the diameter of the pin(s). Shall let you know what I find. Yes, I might need Doug's diff kit after all - Thx James
James Clugston

James, the kit's yours for cost and carriage if you need it. I obviously don't thanks to comments here and from Steve offline. From your photos, something does not seem right. I think that you have the rubber upside down or maybe you're missing something. I could not access TRF's VOL I from here, but Moss has a photo of the diff mounting I'll try to post. Looks like decomposing the PDF is beyond my limited knowledge. The washer should fit flush, that is flat against the rubber. The front mount has two rubber (or urethane, nylatron etc) parts, one "fits" into the other and offers a flat surface for the large washer. The rear is offset with a bracket bolted to the diff body with rubber top and bottom then the pin down through the middle of the rubber, against offering a flat surface for the large washer. Your photo of the rear mount appears to be reversed with the convex end down instead of up into the bracket and the upper rubber mounting. It should have a flat surface on the rubber against which the washer provides support. What's the attachment to the right of your rear maounting? Don't recognize that at all. Check the references for proper fitment and if you don't have CD II, advise and I'll send you one.
db

Doug Baker

Uh...error correction. The 3/8 threaded portion of the pin is UNF, TPI-24.
db
Doug Baker

Doug-Are you sure about the body dia. of the pin being 9/16"? For some reason, I was thinking it was 1/2" (.500").
Berry
BTP Price

James-The duct tape on the front pin might be there to hold the upper mount in place during installation, they have a tendency to fall out.
Berry
BTP Price

Berry,
My new pins indeed measure 9/16th. Don't know about the old ones. Will check tomorrow evening, my "shop" night of the week!!
db
Doug Baker

Good eye Doug, I think you are right, the mounts are up side down. There is an after market supplier some where, don't remember where, who sells machined alum. cups in place of the large flat washers. Apparently the rubber sold now dosn't last as long and tends to bulge out, these alum, cups are intended to prevent that.

Rob
rw loftus

Rob, James,
The machined aluminum cup to be used in place of the large flat washers may be obtained from MOSS, Diff. Mount Stabilizer Cup 680-077 $79.95/pair with what appear to be nyloc or clevenut fasters with lock washers. The others, VB and TRF may also have the product. Did not have their catalogs here to check. Said to help stop any lateral movement in addtion to stablizing the mounting vertically. For fast street and track. Might be a mite harsh for smooth street driving.
db
Doug Baker

The aluminium cups for the diff mount pins are made by Joe Alexander - you can buy them direct from him for a bit less than Moss charge:

http://the-vintage-racer.com//index.php?main_page=product_info&cPath=9&products_id=43

He is a very nice chap and I highly recommend that you look at his other stuff. Saying that, I have the diff mount cups and noticed exactly no difference in the ride, noise etc. I like to imagine that I spent $75 to prolong the life of the mounts if nothing else. If this is not the case then please don't tell me!

Cheers
Alistair
A Hewitt

Gentlemen,

I took off the duct tape and my pins are as Doug suspected they should be: 9/16", and the holes in my new rubber mounts are 5/8" - the holes are quite simply too large, and they perhaps are also the wrong shape. However, I have good news and bad news from a nearby area: the good news is that I have discovered that the DPO actually welded in the angular sheet metal mount strengtheners on the forward diff supports; the (possibly) bad news is that he put them only on the inside of each of the two supports - so the outer sides of the forward mounts are not reinforced - should they not be? (on both sides of the pin/mount?). James
James Clugston

Oh yeah, Doug, the hardware to the right of my diff support is a muffler pipe hangar that came with the car and is/was functional - now you have given me reason to research how the pipe "should" be supported. Cheers. Not sure yet if I will need the diff support materials you have - Shall get back to you soon. btw I do not have CDII. Thx James
James Clugston

James, Thanks for the info. I did not recognize the exhaust pipe support because I removed mine a long time back and just forgot that it should be there. Replaced the 3 or so of those with new rubber and brackets. Send me your postal address and I'll drop a CD in the mail to you. email for me is dbakerATaolDOTcom. Change the AT and DOT to the usual protocols. Good luck with your restoration.
db
Doug Baker

This thread was discussed between 05/06/2012 and 20/06/2012

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