Tie bar front mount

[bmcecosse]

How large should the hole in the tie bar front mount be ?
Have been rebuilding front nearside suspension this morning to try to find a 'clunk' - so far all good except tie bar hole is large enough to push a finger through - and slightly oval downwards. Tie bar was also slightly 'necked' but I have looked out a better one. All bushes are fine and I have fitted a new lower trunnion since I had it in stock anyway - but really nothing wrong with the one that came off.
Just sheltering from a Monsoon at the moment!

[GAS]

I had a similar noise from my ragtop and it turned out to be the bolt ,and more important,the hole in the yoke on the lower suspention arm.It had oveled out and allowed the arm to move forward and back under braking...

[bmcecosse]

Thanks GAS - but all that lot is solid as a rock - had the whole thing in bits - just finished before a second Monsoon hit!
BTW - I'm still looking for a 1275 sump if you have a spare one ????

[MoggyTech]

IIRC there is about 0.5mm gap between the tie bar end and the hole in the tie plate to allow for up and down movement of the tie bar under suspension travel. Certainly not oval on my car though. However the tie bar just limits fore and aft movement of the wishbone and KP under acceleration and braking, so minimal oval shouldn't be a problem, if the tie plate is sound otherwise.

[bmcecosse]

The hole is a good bit larger than the tie-rod - which is reduced diameter at that point anyway. I just can't remember what size it was before. there obviously has to be some room for the tie-bar to articulate and the slight ovality in my case may not be new - it didn't appear to bright metal. To fix it will cause a major fire (waxoyl) - so it stays as it is. Centred it all up with new bushes and washers - and clamped it all up. Just one question - should the nut be wound all the way to the end of the thread ? That is certainly the method on the Mini, just haven't done a Minor one for some years! I did put it to end of thread without exceive force - then I tightened the other end of the bar - and it pulled the bottom arms forward by a good half inch at the wheel end.

[les]

Tighten until the splitpin hole lines up with the nut castleations. I can't remember the exact size of the hole but can say it is quite a bit larger than the diameter of the tie rod; in the region of 9/16''

[bmcecosse]

Thanks 'les' - it's got nyloc nuts, no split pins. i've tightened it to the end of the thread - and a test run shows no knock so far. I suspect the old bushes had gone hard, the outer cup washer had gone convex and the combination may have made the tie rod slightly slack in the hole. I've fitted another rod with 'newer' bushes and a Mini cup washer backed up with a washer under the nut - and wacked it up to the end of the threads! Seems to have done the trick. Thanks to all for the ideas!

[les]

Must admit, without the splitpin to guide me I'd be lost. I thought/think that the bar is there to stop any rearward movement of the lower arm when braking, so only needs to be tightened until the lower arm is slightly 'pulled'. Then again not sure if one of those steering geometry angles is involved, which would necessitate a rethink on my part. Again if a new leg is fitted at some stage, what then, as the location of the tie bar bracket to eye bolt often seems guesswork.

[jaekl]

Ideally I would say the nut should be tightened until the compression in both bushings are equal. How do you do that? Remembering that a new rear bushings needs to be compressed in order to assemble the tie bar, I would target that much compression. In easier words tighen it until there is no force on the bolt in the clevis on the lower leg (slips in and out easily), such that a static car is in a neutral load. Over loading the bushings will cause premature wear (rubber bushings) and I feel the lower leg should have no net force on in in the static position to reduce extra force during articulation. As a starting point the nylon lock nuts should be tightened just enough to expose a full thread. This would simulate the original nut fairly well

[minor_hickup]

If I remember rightly you can tighten the nut far past the castelations with force. But you'd be compressing the bushes, more castor angle though!

[Dean]

I'd guess all this would probably knock the tracking out a tad too?

[minor_hickup]

Yeah probably increase the toe in, it was a tongue in cheek comment. I wouldn't want the bushes too compressed otherwise they might exert more vibration into the bracket on the chassis leg.

[bmcecosse]

Well it runs true hands off - and brakes in a straight line, so nothing horribly wrong there. Monsoon opened up on me just as I was finishing so I had no time to check the tracking - but will do first chance I get.