Rear axle alignment

[Tim Proctor]

We've rebuilt the rear axle and put it all back together. I'm not sure just how the alignment is set. Basically it's off four points: the two diff studs at the back and the two bushes on the rear subframes, with those truly horrible slotted link arms to the floorpan. But all the four points have large holes in the metal work, the actual location being done really by the coned poly bushes on the diff studs sitting into the cones formed in the rear diff plate. I'm not sure how much this controls the location, thinking that if the assembly is offered up slightly skew, the poly bushes will probably grab and stick, rather than do much to line it up because the cone angles are very shallow. Then the skew will be set as the front end is nipped up and set by the link plates.

Certainly on the subframe end, we have a slightly larger gap between the poly bush and the bodywork at one side than the other, and the two link plates don't sit symmetrically.

Can anyone advise?

[edd]

When I rebuilt mine the advise was not to tighten everything up until it's bedded down under some of its own weight. I then took it to be aligned with the front by means of added and taking away the shims on the brackets which control the distance of the trailing arms altering the tracking. Making a note of these original shims may give a clue to what shims you require. The shims are for sale in most stag outlets. It's also handy looking at the search engine on here where more in depth ideas are discussed.
Good luck
Edd

[DJT]

Put a smear of grease on the coned bushes and the surface of the mounting plate where they contact. This will allow the cones to centralise.

This may help regarding the front mountings. It is from the Chris Witor website and, although for the big saloons, the Stag is the same:

rearsuspension.jpg

[Tim Proctor]

Thank you, DJT and edd, so what I need to now is slacken all off, grease the cones, wobble it all around a bit and nip up. Then check wheel alignment, the manual suggests 0 to 1.5mm toe-in for the rear, adjust using the shims.

What is the purpose of the 'rebound washer' ? It all seems a bit Heath Robinson down there.... And why would a single washer above the mounting be chosen over two washers?

[DJT]

What is the purpose of the 'rebound washer' ? It all seems a bit Heath Robinson down there.... And why would a single washer above the mounting be chosen over two washers?

I can't answer that one, but one thing that Triumph's engineers can't be criticised for is the ride quality of the Stag and the Saloons. Both are very comfortable and compliant for what they were, large executive saloons and grand tourers. So if that is how Triumph put them together, then they must have had a reason.

[mike@thenook]

Hi Tim,

to to get the alignment started you need to get the diff mounted on those two pins with the coned bushes sitting neatly in their seatings, it is from these that the diff alignment is set and hence with the the two sub frames, wherever they end up sitting is the correct point using those two pins as the reference.
Once you've got that then the actual wheel alignment is set by the shims on the suspension arm locating brackets, if you've not disturbed those before then they should be ok but worth getting 4 wheel alignment check anyway just to see.
Hope this makes sense

Cheers

[Tim Proctor]

Hi Tim,

to to get the alignment started you need to get the diff mounted on those two pins with the coned bushes sitting neatly in their seatings, it is from these that the diff alignment is set and hence with the the two sub frames, wherever they end up sitting is the correct point using those two pins as the reference.
Once you've got that then the actual wheel alignment is set by the shims on the suspension arm locating brackets, if you've not disturbed those before then they should be ok but worth getting 4 wheel alignment check anyway just to see.
Hope this makes sense

Cheers

It's Tim's other half posting, Louise... The alignment process is now clear, thank you all, we'd been a bit side-tracked by the manual's glib 'to assemble, reverse order of dis-assembly' which kind of misses a few points!

I can't answer that one, but one thing that Triumph's engineers can't be criticised for is the ride quality of the Stag and the Saloons. Both are very comfortable and compliant for what they were, large executive saloons and grand tourers. So if that is how Triumph put them together, then they must have had a reason.

Tim makes the same argument. I'm sticking on it because I know how Tim will hurl this car around the Pyrenees when it's back together and I want to be sure it's right. So I keep asking questions until I know enough to be confident we have got it nailed. And I still don't like this Mickey Mouse bit of the car, it makes no sense at all that all the fore-and-aft control of the entire rear axle falls on a little cranked slotted strap bolted into the floor pan. I will have to accept, in the end, that that is how it is and it works, I suppose.

Louise

[mike@thenook]

Hi Louise,

to be fair as the subframes are both held very tightly in the front diff extension by the 4 large bolts (2 each side) there cannot be much movement at all of the subframe structure if the rear mounts are tight and the front mounts on each side of the body are sound and tight too.
those straps are more of a safety strap than anything but not wise to use the car without them.

Cheers

[mole42]

If you remember that the Stag arrangement is there as a result of many modifications to improve the original 2000 implementation (ISTR there are four different mountings for the outboard ends of the subframe) and that the strap is only an anti-vibration strap, it would seem safe to use the system as designed. After all, they did win the 1970 World Cup with this arrangement on some of the worst roads in South America. Yes, I know Ford claimed the win, but there's lots of people think they cheated.

Richard