Steering feedback and centering

[Markwoodbridge]

Now my car is usable I'm seeking advice on the steering. I suspect the lack of adjustment to the caster angle is the problem but would welcome anyone who has a similar issue and has addressed it with some success. I'd also be interested to know if anyone has a car that doesn't show any of the issues below.

My problem is that I get very little feedback from the steering, there is as good as zero self-centering when I'm going round a corner and release the wheel. There is also no indication from the steering wheel that the rear is about to move away, I'm used to some lightness in the wheel at this point and even some self correction.

I know to get through the self-centering part of the SVA test I has to basically point my two front wheels in different directions.

Any advice welcome. Thanks

[jonclancy]

Hi Mark,

I can't recall suffering the same symptoms as you. Next time the XI goes out (tomorrow - when it stops raining and blowing a gale), I'll have a closer look at my car's behaviour.

I have the geometry and settings checked at Loaded Gunn and apart from a few minor adjustments, TonyL did a bob-on job setting the car up when it was built.

[erictharg]

The Eleven is not great for self centering of the steering. Presumably the geometry has little king pin inclination, but I've never found it to be a real problem on the road or track. But it can be a problem for IVA. Checking the kingpin bushes are free and especially that the top thrust washer is well lubricated and has the correct free play. I've fitted recon king pin assemblies and found that the top bronze thrust washer binds when tightened. Gentle lapping of the bronze washer until you get some free play (vertically) does the trick. Also upping the tyre pressures helps for the test itself.

[Westfield 129]

The Eleven steering centers quite nicely when the suspension is properly set up.

Loosening up the king pins helps quite a bit, as does removing friction from the steering rack and the suspension bushings.

Every 11 I have set up had problems with the steering not wanting to self center. All were fixed by setting the toe properly (along with the ride height, and camber). All the cars had a problem with excessive toe out, and very tight king pin nuts on the upper arm.

Once properly adjusted, the steering is lively, and has lots of self centering.

[Markwoodbridge]

Thanks to you all, some great points to check over. I'll let you know how it goes.

[Markwoodbridge]

Hi all
My only guide to setting up the stub axles is the MG Midget Haynes manual, Does anybody have any other better guides?
At the moment I know that if I tighten the nut on top of the trunion to the recommended 40 lbf ft torque then the steering hardly moves at all.
Thanks, Mark

[erictharg]

If tightening the nuts at the top of the kingin are causing the steering to tighten you have two options. Buy some of the factory shims and add them to the top of the pin until tightening the nut does not cause the swivel to bind on the bronze thrust washer. I'm guessing any of the Midget specialists will keep them.
Or, remove the track rod end (so you can feel how free the swivel is on the kingpin) and tighten the nut only enough to remove excessive vertical free play, and still allow the swivel to pivot freely. It should be a nyloc nut, and not torquing it to the full spec won't cause any problems - it doesn't receive any rotational movement that could loosen it off.

[Splat]

Yes and no!

At age seventeen I found myself upside-down in a ditch in my first car, a "frogeye" Sprite. It had failed its MoT on excessive free-play of the upright on the kingpin. The garage replaced the phosphor-bronze thrust washer and re-shimmed, but re-used the old Nyloc. Within 30 miles the Nyloc had unwound, the kingpin had dropped through the trunnion, the wishbone locked the front wheel and the car spun and flipped. I was lucky, but the car was a write-off. With the help of the AA (who provided a damning inspection) I successfully recovered all from the garage (I was TPFT only).

Replace the thrust washer, re-shim accurately, and renew the Nyloc on the top.

[erictharg]

I understand what you are saying but I still fail to see how even a plain nut could loosen from the top of the kingpin. It is held in tension by the force of the suspension spring holding the weight of the car off the road, and so should never be "loose". It also never sees any torque from the swivel itself as it sits against the top wishbone trunnion.
But stranger things have happened, and there could have been all sorts of other factors involved.
I confess to still using the same nuts that I used when I built my car 6 years ago. They've not moved in all the miles of road and race I have done. However, new nyloc nuts are always a good idea.

[Splat]

Prior to Nylocs, the kingpins were drilled and castellated nuts with split-pins were used. The constant vertical hammering of the stub axle on the underside of the trunnion slowly drifts the nut up the threads if it's not correctly secured (re-used Nylocs or no split-pin). Of course, this doesn't happen when new as there's no vertical movement (of interest, the shims used to be available in a couple of thicknesses, but the thinner one seems to no longer be around, so initial set-up can't be achieved to such fine accuracy), but as the thrust washer wears (as a result of steering rotation) so play is introduced. Trust me on this; you don't need rotation, just the relentless hammering of the trunnion into the underside of the nut, slowly forcing it up the threads.

There is a simple and cheap solution. A pair of new thrust washers, a handful of shims, new Nylocs, a Haynes manual and a little patience in setting it up. You'll have to disassemble and reassemble a number of times as you add or remove shims until it's correct when fully torqued, so reuse the old Nylocs throughout the process until you've got the shim stack spot on and then finally replace the old nuts with new ones. A bit of paint on this safety critical nut will then act as a telltale to help you check that it remains tight.

As an aside, this was always a Spridget weak point. BMC's service advice was to grease the uprights every 3000 miles, preferably with the front jacked and whilst exercising the steering. I learnt all of this the hard way as a result of very nearly having to go to court.

As an aside to my aside, I've restored my Westie using the Haynes manual I bought in 1988 when I bought the Frogeye......