Front suspension top links

[ndevans]

Evening.
I'm replacing the bushes in the top links with poly bushes, as the original rubber ones date from 1991, and look a bit shot.
(Actually, on dismantling, it turns out the top bushes are poly-dunno when they got put in, wasn't me guv, when I rebuilt the front suspension with new kingpins, trunnions etc in '91, after a bottom trunnion failure, I put in rubber bushes )

My question is this. The workshop manual goes into a fair bit of detail about 0.05mm end float, and an overall length of ~79mm from the front of the damper eye to the rear of the pivot nut.
Does this only apply to models WITHOUT bushes in the top links? If so, are the pivot pins in rubber bushed top links self-centreing? How far up do I do the rear nut on the pivot bolt?

cheers N

[philthehill]

The end float only refers to those early top links with screw threads.
The top links fitted with rubber/poly bushes do not need and should not have any end float.
The bushes are fitted and the outer large washer/nut done up against the step on the pin and the lock washer knocked over.
Some later after market top pins have UNF threads and a nyloc nut can be used instead of the plain nut and lock washer but the large washer is still done up against the step of the pin.
The new bushes can be given a smear of red grease before fitting.

[ndevans]

Ok thanks.
Is there a torque setting, or is it just "good and tight"?

[philthehill]

Just good and tight.

[johngrigg]

This site is amazing! here I am poring over my 3 manuals scratching my head wondering how you can accurately measure 2 thou against a poly bush, finally give up and look at new posts and there is the answer! Thankyou Philthehill but pray tell what about the bottom link? one of my manuals suggests a similar clearance for these or is this only for ancient cars? mine is a 1960 1000. Cheers
John

[philthehill]

John
The reference to the 0.002" in Wksp Manual Section K4 - Replacement para 4 refers to both the screwed top link and suspension with the rubber bushed top link.
When assembling the bottom thick/thin arm to the bottom trunnion pin - so long as the bottom trunnion is able to freely rotate about the bottom trunnion pin all will be well.
Unless you have facilities to grind the pin when the clearance exceeds the 0.002" as described in the wksp manua lthe only way to get the exact clearance is by trunnion pin selection. If the clearance is less than 0.002" and the bottom trunnion will not rotate around the trunnion pin i.e is tight all you can do is select an appropriate pin to give the required 0.002" clearance.
So to re-cap - unless you have grinding facilities and/or a good selection of trunnion pins the production standard has to be accepted.
The Marina bottom trunnion pin I have found is produced to a much higher standard, has a case hardened surface and they are what I use. The trunnion pins dimensions are the same and the trunnion pin seals are also of a much better material. There are plenty of NOS items on 'e' bay. The only down side is that the trunnion its self is not suitable for use on the Minor as the swivel threads are of a larger diameter.

[ndevans]

When you say "rotate about the trunnion pin ", do you mean that the trunnion should turn freely on the kingpin, or do you mean that the pivot pin inside the trunnion should be able to rotate?

Cheers N

[philthehill]

The bottom trunnion pin does not rotate as it is hard gripped either side/end by the thick and thin suspension arms
The bottom trunnion should be able to freely rotate around the bottom trunnion pin (when disconnected from the top trunnion pin/rubber bushes) but of course the arc of free movement is limited by the bottom thick/thin suspension arms.

[ndevans]

I think I see what you mean. So with the kingpin disconnected from the top trunnion, damper arm and steering arm, and with the bottom trunnion on and the front and rear lower arms assembled in place, the trunnion should move freely on the trunnion pin?



My brain hasn't booted up yet!

Cheers N

[ndevans]

Ok last question (for now!)

Tie - rods. How far up should they be done? I guess that if they are not adjusted evenly then you get uneven tyre wear?

Cheers N

[philthehill]

The tie rod nut should be tightened until the front steel washer just abuts the shoulder of the tie rod. Any tighter and the washer will deform as in most cases the shoulder is found to be not square as it should be.
The best tie rod bushes to use are those with a raised centre boss which fits into the centre of the tie bar chassis leg bracket and stops the tie bar rattling against the bracket.
If fitting poly bushes - try fitting the poly bush to the front and a standard bush to the rear. The poly bush helps with holding the suspension under braking and the rubber bush helps with the articulation of the front of the tie bar.

[johngrigg]

Thanks again Phil. Now that its the weekend, and armed with your advice, I shall have another play with the front end which at the moment is either squeeking or seems to be locked solid but not both at the same time, hopefully adjustment and lubrication will set it right. Cheers John