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MG Midget and Sprite Technical - Steering Rack

I am currently degunking a steering rack to go on my new build 71 car and wondered if you experts out there could help with a couple of questions -

Apart from new track rod ends and gaiters is there anything else I should be replacing or checking?

There doesn't appear to be a grease nipple anywhere so how does one lube the rack?

What sort of paint and colour should the rack casing be?

Many thanks

Nigel
Nigel Pratt

I'd check the rack and pinion for wear and general condition; similarly the balljoints at the end of the rack.

I think a '71 uses the early rack, which is lubricated by EP oil; is there a hex plug above the pinion you can remove for this purpose?

A
Anthony Cutler

The rack is a later one as its off a 73 car. There is a small plug screwed into a much larger one on the pinion joint which are described as dampers in the book.

There is still a lot of what looks like LM grease on the rack as its moves in and out.

Perhaps I should try putting some grease/oil in through the dampers?
Nigel Pratt

The 73 uses the Triumph rack and expects grease. Simple rule of thumb: if it came from the factory with a grease fitting, it wants oiled. ;-). You can remove the small plug and fit a grease fitting to it so that the next owner will be suitably confused. BTW, the Triumph rack is a slower ratio (more turns lock-to-lock) than the Morris unit used on the earlier cars.
David "grease monkey" Lieb
David Lieb

Hi Nigel

If you are using a later rack (compared with your original fitment), IIRC you should use the later steering arms as well. The originals will work, of course, but will give the steering a slightly different geometry.

A
Anthony Cutler

the steering arm mismatch must be avoided as IIRC the hole for the TRE is both a different taper and size...
David (davidDOTsmithAT stonesDOTcom)

IIRC the later Triumph rack uses different mounts to the earlier rack but do they bolt on the same as the earlier ones?.
David Billington

"but do they bolt on the same as the earlier ones?"

Yes
Deborah Evans

The rack clamps are usually fitted with shims to ensure the rack alignment is correct, and so that there is no stress put on the steering column alignment at the scuttle clamp. Bad alignment can effect the self-centreing of the steering which sort of links with that other recent thread!

Guy
Guy Weller

The early rack uses alluminium clamps/mounts, whereas the later rack has pressed steel mounts. They do attach to the same points on the crossmember.

As David Smith says, the steering arms are very different. The holes for the TREs are a different size. The TREs cannot be swapped between racks as the track rods are a different diameter.
Dave O'Neill 2

The gaitos are also differant...to fit the later rack, one side has a thick housing the other is thinner.

yeah your in modified hades...enjoy the scenery

prop
Prop

The Argentine replacement rack for the 1971 does not have grease fittings. The interior parts and rack ends are modern plastic fittings that do not require routine lubrication. You may have obtained one of these from Moss or one of the suppliers that sources racks from Argentina.

Mine now has a bit of play in it so I am looking to tighten the plug that hold the nylon rack bushing in place.
Glenn Mallory

Mine now has a bit of play in it so I am looking to tighten the plug that hold the nylon rack bushing in place

The Argentine replacement rack.

So should we cry for you.....Argentina ?
M. Who

Gents
Slightly off thread question:
Is the splined shaft on the later UK type collapsible steering column the same as the earlier steering column ??
I want to fit the steering column from a 73 (triumph type rack) to the early steering rack from a 67 bitser car that I am building somewhere in the future.
The best of both worlds : earlier steering rack (quicker ratio) with the later safer collapsible sterring column.
Ian
Ian Webb '73 GAN5

Hi Guys and Deborah
Ian mentioning threads reminded me of a nasty little trap with non collapsable midget columns.

Make sure the bolt you use through the bottom fitting/clamp of the column where it clamps to the splined shaft of the rack isn't threaded all the way up. It needs to have a solid shank where it passes through the clamp past the splined section of shaft. The DANGER being that if you use a bolt that is threaded all the way up and it happens to get just a little loose the column can be pulled off the rack as the threads of the bolt slide up the splines of the shaft and it will happen when driving hard and pulling on the wheel a bit more than usual. Check that bolt Cheers Willy
WilliamRevit

Indeed Willy.

Not to mention the fact that a fully threaded bolt is liable to failure owing to the threads in the loaded area of the bolt acting as stress raisers.
Deborah Evans

Ian Webb '73 GAN5, 67 GAN4 & 59 Frogeye, Northamptonshire, United Kingdom
Gents
Slightly off thread question:
Is the splined shaft on the later UK type collapsible steering column the same as the earlier steering column ??

The 1971 and later column is splined for a .625" male spline on the pinion shaft. So I would say yes.
U prolly will want to modify the jacket and remove that goofy key lock and maybe shorten the assembly....but no big seal. The early cars might need a little sheet metal on the above part of the firewall above where the jacket fits as the late piece is a bit bigger.

Posted 26 August 2009 at 14:53:26 UK time
WilliamRevit, Tasmania, Australia
Hi Guys and Deborah
Ian mentioning threads reminded me of a nasty little trap with non collapsable Midget columns.

Make sure the bolt you use through the bottom fitting/clamp of the column where it clamps to the splined shaft of the rack isn't threaded all the way up. It needs to have a solid shank where it passes

All rack pinion clamps need a proper length and grip length with no threads. An AN3- (about 14) airframe bolt will be about right depending on the exact length you need.
M. Who

This thread was discussed between 19/08/2009 and 27/08/2009

MG Midget and Sprite Technical index

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