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MG MGB Technical - Rack and Pinion steering lubrication

Just about to fit a new Rack and Pinion unit which has been stored in the loft for 20 years or so. It seems quite stiff and there is some suggestion of oil/grease evap. Anyone know how the later type unit is (was) lubricated ?

Roger
R Walker

Roger-
Refill the steering rack with 0.4 US pint (½ UK pint, 0.2 liter) of EP90 hypoid gear oil. Do not overfill the steering rack as this thick and viscous oil flows slowly from one side of the steering rack to another. Overfilling can result in a ruptured gaiter (boot). Under no circumstances should you attempt to substitute grease for oil. The rack itself acts much like a double-ended piston, with the gaiters being the cylinders. This action causes the oil to move around and lubricate everything, including the inner tie rod ends, which grease does not do. There needs to be a pressure equalization vent between each of the gaiters and the body of the rack housing. On the steering pinion side of the housing, the rack teeth cutaway lets air / oil move past the bush, but on the other side you need either a hole or a channel cut in or around the bushing so that the pressures can equalize. Be careful about cutting slots in the bushing, because if you overdo this, then the bushing will fall out! It could also be a flat cut on the rack, just like the other side but no teeth. This venting is even more important when some idiot pumps a lot of grease into the steering rack. When "grease lubricated" prior to assembly, there should be only a smear of assembly grease on the bearing points, and there must be enough leakage past the bushing in order to allow air to move through. The problem then is that, after some time, the grease will move away from the actual critical areas, and then things will wear out if you don’t keep the steering rack filled with EP90 hypoid gear oil.
Stephen Strange

Stephen,
Thank you - that has triggered a very distant memory and is very helpful.
Roger
R Walker

How do you stop the rack from leaking? Mine has always dripped from the pinion housing despite numerous attempts to replace gaskets etc.
Mike Howlett

Mine too. I had to change one boot on the roadster and one on the V8 some time ago. There hadn't been any oil dripping from either, both were wet with oil inside, but they certainly dripped afterwards! It can come from the damper cover, the pinion bottom cover, and the pinion oil seal amongst others.
PaulH Solihull

Has anyone used/tried the Rakboot replacement rack boots sold in Australia? There is a Youtube video showing how to install. Looks pretty slick if it works as shown.

Pat
Patrick Callan

Echoing SS above, we found out Moss ships their current batch of racks: "Perlubed for life" or thereabouts, with red bearing grease only, no 90 wt. And they ain't right. Regardless of the supplier claim, the 90 wt makes it right. Steve- How about just poking holes in the gaiter tops to vent 'em? :) Cheers, Vem
vem myers

"How about just poking holes in the gaiter tops to vent 'em?"

And let dirt and water in ...
PaulH Solihull

ahh Paul- you've known me long enuf to know when I'm joshing...besides a little dirt and water will maintain viscosity and lubricity, no? Cheers again Vic
vem myers

Gaiter vents, an excellent idea! When the rack heats up, from use, the moisture will escape through the holes. Vem, you are truly a genius. RAY
rjm RAY

If there is any water present at the holes it will be pulled in to the gaitor as the rack cools down.

Ronnie
RA Potter

SS - followed your advice - last time the steering was that finely directional was on my first B.....1962.
R
R Walker

Ronnie, in all seriousness, the rack assembly is a sealed unit when the rack boots are in like new condition. The factory racks used 90W gear oil for lubrication, but the aftermarket racks, manufactured in Argentina, use grease as a lubricant. RAY
rjm RAY

Ray- Thanx, I am a genius. And to keep an overheating engine cool, I drill small vent holes in the head, about #43 drill bit size, between each sparkplug! Vic
vem myers

POSTSCRIPT
New Rack (90 grade oil) + New steering column = transformed steering (the V8 goes exactly where it is pointed).
R Walker

Hi Ray

I am new to MGB and having a new rack it will be a long time till I need to do anything there. I am nearly finished rebuilding the motor and the biggest problem I have had is trying to keep the garage warm!!!

Ronnie
RA Potter

Ronnie, these racks are pretty tough units. My '67B still has the original one. I've change the rack boots three times over the forty years that I've owned this car. A little maintenance can make these cars last a lifetime. I hope you find the enjoyment that I, and almost all of the other B owners posting here, have found in owning and driving these most unique cars. RAY
rjm RAY

Vic, isn't that the same drill size you used on the SU HIF44 carburetor on your supercharger? RAY
rjm RAY

Ray - same situation; 41 years, 300K english miles. The rack had some play and the column rattled. A touch on the wheel now and the car responds again - what a joy they have been all these years - particularly when you recall their predecessors with worm gear !
Roger
R Walker

I am always amazed at how precise the steering is in my B. There is absolutely no play whatsoever in the steering wheel or up and down movement in the column. The only front end components, that I have replaced in the 40 years that I've owned this car, are the outer tie rod ends and the lower inner A arm bushings. Just the slightest movement of the steering wheel has the car in the next lane. RAY
rjm RAY

Ray, yep, you're right and certainly a genius too. I'm going down to #42 today to see if I can get the take off stumble smoothed out. I've got over 1M miles on the 70 B bought new, with smiles and memories up the wazoo. Vic
vem myers

This thread was discussed between 21/11/2012 and 08/12/2012

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