Dodgy steering

[Tea]

We recently got a 1971 traveller from a friend who had said he never felt comfortable with the steering but couldn't work out what it was. We've now finally become annoyed with it as well, so thought I'd ask to see what the issue may be.
When going over a bump, pothole, up a kerb, etc. the car and steering jolts fairly violently one way or the other and can produce a slight snaking motion when going down the motorway. Also, If you turn a corner the steering wheel doesn't go back to centre by itself.
So far it has had a new steering rack, bushes all round, track rod end and plenty of fresh grease, all of which have made no difference. There is no play in the trunions either.
I'm convinced it's coming from the front of the car as the steering wheel jolts pretty badly, but my girlfriend thinks it's the at the back.
Does anyone have any ideas of where to look to next?

[panky]

My first instinct would be to check the tracking.

[simmitc]

Front end - tracking, wheel bearings, damper mountings, bump stops.
Rear end - spring hangers, U-bolts, bump stops.
Both - check wheels & tyres for damage. Is the structure of the car OK - no flexing or other damage?

[bmcecosse]

If the car has had a 'frontal' at some point - the steering geometry may be upset - and if there is not enough caster angle - that will certainly cause the lack of self centering you mention. Inspect carefully - and perhaps get a Caster angle and Camber angle check at a competent garage. Since you say it reacts badly to bumps - I also thoroughly recommend draining the dampers and refilling with sae 40 oil (not 10W40) which seems to be readily sold for compressors etc. However - the vagueness etc may indeed be coming from the rear axle if the 'perches' which locate the axle on the springs have rotted away - allowing the axle to twist as the car moves. Worth checking too that the rear springs are ok and no broken leaves !

[Tea]

Many thanks for the replies - I'll be checking the suggestions out over the course of the week and report back. For the time being I know that the structure of the car is sound and has never been in an accident. We've recently had the car go through an mot by the garage used by the local MG owners club who said it's as clean underneath as it is on top (which is immaculate) making it all the more frustrating that the steering is a tad buggered.
Thanks again.

[mike.perry]

Jack the front of the car up and turn the steering from lock to lock with the tyre. You should also be able to remove the front wheels and turn the steering with the brake drums

[firehor5e]

try measuring from rear wheel rim to front wheel rim on one side of the car.then compare measurement to the other side.also,a plumb line tied to centre of front bumper,while wheels are straight.turn steering too full lock,the plumb line should rise.then fall as steering is centered and rise again as turned to opposite lock.

[bmcecosse]

Why would it do that??? As standard - the Minor doesn't have negative camber -just positive camber which progressively gets worse as the steering is turned...

[Tea]

Unfortunately I've not had time this past week to check the car out properly and as I'm away for a month from Thursday I'll be having the tracking checked as soon as I'm back.

For now the only two developments I can see from a quick check is that the front tyres are COMPLETELY bare with zero tread on the inner third of the tyre - the other 2/3 are like new. I had previously thought that the wheels looked as though they were on a wonk (a bit like "/ \" when looking straight on), but after straightening up the car they looked fine. I think this shows that I was right with my first check over.

I'll be updating in mid-Jan when home, so thank you for now and I'll be back to pick all of your brains soon

[bmcecosse]

If the tyres are that badly worn -there is either desperate amount of negative camber - or the steering is seriously mis-aligned. A tape measure will give you a good enough reading to check that at this stage !

[Tea]

I'm just back from having some new front tyres put on and the tracking done. So far so good. It's difficult to say for certain it's back to how it should be as I'm not sure that we've gone over a bump that was 'bumpy enough' to properly test it with the roads between the garage and home being relatively smooth and new.
The steering wheel still has an issue with self-centering so I'll start investigating that soon.

As always thanks for the help and suggestions.

[mike.perry]

Tie bars tight? New bushes?

[bmcecosse]

And did they have to change the tracking setting? If it's not 'self centering' - then could be the swivel pin(s) and/or steering rack are seized - or there is insufficient castor angle. Did they check the camber and castor angles? It should self centre quite strongly....... If it doesn't - then I suggest it is too dangerous to drive till you find and fix the problem.

[Trickydicky]

More importantly what did they set the tracking too? Most garages today don't have the settings for a minor in there databases.
From memory it should be 1/8" toe in which equates to I THINK 1.25 degrees each side.

[Tea]

Tie-bars are fine and new bushes all round.
The did have to change the tracking setting, but to what I do not know.
I forgot to ask about the camber and caster angles - something I will do when I'm next over there. For now I'll have a close look at the swivel pins and steering rack. Although the steering rack is new ('new' as in bought new a good few years ago, but only a handful of miles prior to our 2,000 since the summer) it had sat and not had more than a hundred or so miles done on it in 7 years, so I assume it could well have seized in that time?

[Tea]

Sorry, the camber was checked and corrected - a little too -ve. I'll blame my current fever for forgetting that one and checking the paper work

[bmcecosse]

Your steering rack will be fine. I wonder how they 'corrected' the camber - as standard on a Minor it should actually be slightly +ve to zero. Having a little negative camber is good - and usually leads to even stronger self centering! But it's only 'adjustable' by dismantling the suspension and adding or removing washers at the connection of the bottom arm eye-bolt to the chassis leg. I rather doubt they did that... I suppose they may have manged to slip out a U shaped washer if there was one in there....but seems unlikely. The biggest influence on self centering (assuming the king pins are not seized) is the Castor angle. Too little - and no self centering.

[philthehill]

The 'U' shaped washer (Pt No: 183471-Z in the drawing below) should not be removed if the top trunnion has rubber bushes. The washer was installed when the top trunnion pin was changed from a screwed fitting to the rubber bushed installation.
The camber angle is set by the body fittings i.e. the eye bolt chassis hole and the damper mountings - if it has to altered something must have happened or someone has done something to require its adjustment.
This is the set up for the eye bolt with rubber top trunnion pin bushes.[frame][/frame]
The caster angle and king pin (swivel pin) inclination is set by the chassis mounting for the tie rod and the correct placement of the eye bolt hole.
Has the chassis rail been replaced at some time in the past?
If it has and it has not been installed correctly it could effect both camber, caster and king pin (swivel pin) inclination.
Phil

[Tea]

I don't think the chassis rail has been replaced. At least I can't see any evidence of a replacement. Thanks for the diagram, I'll be printing it out to add to my folder.

I took the car for an hours drive today to see what the handling is like and it feels great to drive. It does try to self center but is just quite sluggish in getting there - it doesn't have the same 'lightness' as our saloons.

Possibly just needs very minor adjustments to get it to pull with a bit more umph?

[liammonty]

Does the steering feel totally free when the front of the car is jacked up? Are the trunnions ok, as if they are well worn they would stiffen the steering (as mentioned previously). If you check it with the car jacked up, you would know whether it is a mechanical issue, i.e. Trunnions or a stiff rack (which I have had with a recon unit), or if it's the steering geometry that's still out.