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MG Midget and Sprite Technical - Steering rack

Got a new steering rack from Moss for my Mk2 Sprite.
The dia’s where the mounting brackets locate were oversize and not very even, the mounts didn’t fit properly. Ended up filing them to the same size as existing rack.
Has anyone else had a similar issue?

Also noticed that I haven’t got the shim that should be fitted to the near side mount, not had one for 25 years! As it happens I have a spare bracket that has a shim with it, so might fit the shim - what is it’s purpose?

Les
Les Robinson

Les, my understanding is that the spacer ensures the pinion is at right angles to the rack as the steering column is offset in relation to front to rear axis of the car.
Bill Bretherton

Bill is right. Rack designed for a car (Morris Minor, or was it a Triumph?) where driver was seated further out from centre line of the car, and steering column therefore angled out a little more. Shim reduces that angle to suit the narrower Spridget seating position.
GuyW

Not just the narrower seating position. The Minor rack is behind the engine, whereas the Spridget rack is in front. The much longer steering column of the Spridget would put the wheel further out, without correction.

Dave O'Neill 2

Guy
The rack is a LHD Morris Minor part.
Will fit the spacer.

Having to file the rack casing where the mounts fit was bit of a phaff, is this a common issue? Was definitely oversize.
Les Robinson

I live and learn. When I bought my car it had two thick shims under the rack brackets, ie one each side. During the rebuild I could see that there had been accident damage, with some chassis welding, and previously I had to have the cross member that holds the rack cut out, straightened and welded back in. I thought the shims were there to get everything lined up properly after all this repair work and didn't realise there should be only one on the near side.

Then recently I fitted an aluminium radiator. The only way I could get it in was to remove both of these shims and file both the radiator and the brackets. But I don't quite get is that the forward end of the rack is angled inwards, so it meets the rack at more than 90 degrees. Adding a shim to the near side and not the offside will increase this angle, which seems odd. Anyway, I have been running the car for 45 years with the rack either shimmed both sides or not at all. Am I likely to have damaged anything?
Les Rose

I have now fitted the shim to the offside bracket, prior to that not had one for 25 years.
The steering column now fits easier, can easily push it into place. Previously had to give it bit of a gentle smack with a mallet to get it engaged.
Changed the rack due the excessive play in the tie rod ball joints. Rack was a recon one, 25 years old now. For years there was very slight play in the off side tie rod, never an issue for MOT. The drivers side had always been fine however within a few months it has gone really loose with loads of free play!
Les Robinson

Shim fitted to near side, not offside !!!
Les Robinson

I was just looking at the official parts list, which I have as a massive printed tome! The shims we are talking about are called packing pieces, and are available in 3 thicknesses. The diagram only shows one on the offside, but under "number required" the list just says "as required". So I looked at the official workshop manual, but I have owned since 1972, to see what "as required" means. There is not a word about it. The diagram in the manual for some odd reason shows a left hand drive car, with a packing piece on the other side, ie still on the driver's side.

This is all pretty academic, as I couldn't fit a packing piece to either bracket, or it would be impossible to fit the radiator. I'm just curious about the effect these pieces have on the geometry of the steering column and rack.
Les Rose

Mine has a packer, or maybe more than 1, I don't remember. It's on the nearside i.e. left side, right hand drive car. Given the distance between the rack mounting clamps the addition of a relatively thin packing must produce a very small angular adjustment to the rack. 1 degree? Less than that?? One could do the maths to work it out. So it translates to a pretty small lateral re-positioning of the column at the top end. It's nice to get it right in engineering terms, and should result in lighter steering. But I suspect wear on most cars probably provides a similar amount of 'adjustment' !
GuyW

The column on my Heritage bodied Sprite is very close to the edge of the hole in the bulkhead that it passes through. I thought this was a quirk of the new body but now need to check out the rack shims since a lack of these could have moved the column off centre.

Jan T
J Targosz

One thing to remember when checking rack shims - the shim is fitted to the passenger side for the Morris Minor derived rack, but the driver’s side for the Triumph rack.
Dave O'Neill 2

This thread was discussed between 15/05/2024 and 22/05/2024

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