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MG Midget and Sprite Technical - Rack Pack

Doing a bit of maintenance on the car I found that my steering rack was moving side to side in the alloy clamps, despite the bolts being tight. Very tight. Needed heat to shift them and set fire to the car in the process.

Anyway, ignoring that for the moment, the clamps need some sort of packing material. When I assembled it last time, getting on towards 20 years ago, I wound layers of self-amalgamating rubber tape around in the belief that this would allow the clamps to tighten down, but would also deform enough to avoid cracking the alloy clamps. They are vulnerable. It worked well at the time, but over the years the tape has continued to "flow" so now they are loose.

20 years for a method isn't bad, so I could do the same again, but what do others do? Any special tricks or shims I should be using this time?
Guy W

I used masking tape when I did mine years ago and never had any problem with that. It didn't require very much either and yes I know the mounts are fragile as I have cracked one in the past.
David Billington

Seem to remember mention of inner tube material.
Should be something that does not absorb water.

EPDM sheet cut into a strip may be a good material - used now for air/water sealing curtain walling / windows to perimeter interfaces on most large building sites.

May have some bits if you need some - about 1.5mm thick.



R.
richard boobier

Not certain the type of clamp you have Guy as i know the later ones may be different, but the frogeye ones use a paper gasket, similar in thickness to the rear hub seal.

Mine have held firm for the last 50 or so years since the car was built!
Bob Beaumont

Ive never shimmed mine...

unless you count a dog pissing on it

Prop
Prop and the Blackhole Midget

Bob, that's useful to know for the "other car". That's what the sticker in the back of my Sprite will say - "My other car is a Sprite". Or maybe it will say "I would rather be driving my Sprite"

This Sprite uses cast alloy, not fabricated steel rack clamps like the early ones. The alloy clamps have a habit of breaking if the packing is too tight, or to thick. That was the advantage of the self annealing insulating tape. Its quite squashy, but wound in layers it fuses to itself and builds up into a solid packing piece whilst remaining soft enough to compress as the clamps are tightened up.

Think I have answered my own question haven't I ?!
Guy W

I bought the proper paper shims and they worked fine.

The alloy brackets ARE the early ones. They changed to steel for the Triumph rack in '72.
Dave O'Neill2

Dave,
I found a pair of the welded steel clamps in a parts box, and assumed they belonged to my Frog which is currently fully stripped out. There must be another alloy pair knocking about somewhere!

On the '71, if the rack is assembled into the clamps without packing, there is side to side play of about 1/16". So it relies on the packing to grip the rack firmly. I wonder if they were ever shimmed for lateral movement? I think I might try that. I suspect the sideways slack is necessary to allow for manufacturing tolerances between the two clamp positions, but I could trial fit and then just make a C shaped shim for one side.

PS Annoyingly, I set fire to the 4" air duct and I have a suspicion these are no longer available. Unless someone knows otherwise? I don't want to end up using a nasty white cooker hood duct!
Guy W

Guy . moss sell the 4" duct but it's corrugated the whole length instead of having the smooth centre section.

Also, when I rebuilt my midget I had a problem with the horn (centre push) which I tracked down to having too much insulation in the steering rack clamps so there wasn't any eathing for the horn.
graeme jackson

Guy, Not aware of any shims to stop lateral movement. I assume without the packing the rack is still tight in the clamps?? Movement may well cause a stress fracture of the clamp. I would stay with the packing personally!
Bob Beaumont

No Bob, that's the point. The rack is not tight in the clamps without any packing. It moves laterally (from side to side)by about 1/16". There is also slight rattle (vertical play) between rack and clamp, but that is what the packing allows for, so long as one doesn't add too much and crack the clamps!

It may be that, with packing added, there is enough frictional grip between the compressed packing, clamp and rack, to prevent lateral movement, and perhaps that is how it is supposed to be.
Guy W

If the rack is not tight verticaly then I would certainly use packing. Can't then see the need for an additional shim??
Bob Beaumont

Yes, I would always use packing anyway. That's how it was designed. Anyway with new packing material it is now good and tight again so it has all gone back together.

I spotted this when doing the monthly greasing of the suspension. I thought at first that the inner ball joints on the track rods were worn, but then realised that the whole track was moving. Just shows it was worth a closer look!
Guy W

This thread was discussed between 20/08/2013 and 22/08/2013

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.