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MG MGB Technical - Argentine Steering Rack

I have one of those Steering Racks (Made in Argentina)on my, 71BGT. And was having some issues with heavy steering and the steering wheel not centralising when making turns.
Looking through the archives I found some people with these Racks,cleared out the grease and replaced with Gear oil, Some of the Racks appear to over adjusted (Too Tight)when sent from the factory,at the pinion/rack.
However their is an easy adjustment with slotted screw and lock nut,No shims are used. I did find this adjustment to be too tight.
Fitted new Good quality Gaiters clips etc. cleaned out the grease,and replaced with 1/3 Pint of Gear oil,which I put in through the small hole where the screw and lock nut go, slackened off the adjustment screw on the rack till I had a nicely moving rack,which is now moving easily,and is much better than before and does seem to centralise now. (Nice Job Done I Thought)
My Problem now is, I have noticed when turning the steering at full Lock in either direction the Rubber Gaiters/Boots seem to colapse on themselves as if all the air is being sucked out of them and a vacume is being created within the steering rack, oil also appears to be being pushed out from where the steering pinion shaft enters the rack,just a few drops every time I move the steering from lock to lock,I can also hear air escaping from the same place.
I do realize these racks are supposed to have grease and not oil in them, But I filled them with oil after reading many threads which owners said was a worthwhile modification and had been done sucessfully.
If I was to do this job again I think I would have used grease,
Can anyone please tell me why there appears to be this vacume now in this rack,
Also Owners with these Steeringracks fitted and thinking of switching to oil instesd of grease pleased be advised of my experience.

Many Thanks, Malc
M Brady

The rack acts as a double ended piston, with the gaiters being the cylinders. There needs to be a pressure balancing vent between the gaiters and the centre of the rack housing. On the steering side, the rack teeth cutaway lets air/oil move past the bush, but on the non steering side you need a hole or a channel cut in or around the bush, so that the pressures can balance. It could also be a flat cut on the rack, just like the other side but no teeth. This action is what causes the oil to move around and lubricate everything, which the grease does not do.

This venting is even more important when some idiot pumps a lot of grease into one of these racks, or even the OE ones. When "grease lubricated", there should be only a smear of grease on the bearing points, and there is enough leakage past the bush to allow air to move. The problem then is that, after some time, the grease moves away from the actual critical areas and the thing wears out - hence "lubricated for life"; life is until the lubrication fails.

I've never seen the repro rack, so I do not know what sort of seal is on the pinion shaft, but relieving the pressure should reduce if not cure any leakage there.

FR Millmore

At least 10 years ago, I purchased an Argentine rack from Moss. I saw it was filled with grease. At that time Moss did not advise about the grease. So I fell back on the old oil filled rack directions which warn against using grease.

I removed and flushed the grease a best I could. Then I filled it with 90 EP. I did notice there appears to be no seal on the input shaft. A few drops of oil came out at this area initially but since then no problem. By the way there appeared to be way too much grease in the rack.

My rack does not have any collapsing gaiters or noise when moved from stop to stop. I suspect you are gong to have to solve the pressure/vacuum problem if you are going to stop the oil loss. Could be some grease has clogged balance paths.

If I bought a new reack I would just leave it greased and adjust the preload. I believe all contemporary auto racks use grease not oil. They likely use plastic inner tie rod sockets. Also, the preload mechanism is now plastic rather than metal. Hence, they can get by without oil. They probably won't last as long thought.

If desired, you may be able to drain the rack, dissassemble and go back to grease. Getting grease into the inner tie rod assembly may be a problem depending on the design.

Best of luck.
Robert McCoy

Many Thanks FRM,
So what I need to do,if I am to understand you correct,is to remove steering rack, and put a notch in the rack where it passes through the bush on the non steering side or drill hole,or cut slot in the bush, on the non steering side, to relieve this pressure
Have I got that right!

I may be wrong but I did not see any type of seal where the pinion shaft engages into Rack housing.

I wonder why on all the previous threads, I read up on, this problem was never mentioned,or seemed to be encounted by anyone.

Many Thanks
M Brady

Unlike your rack, When I dissasembled mine, I found There was not much grease left in there at all, especially on the non steering side,
I think the way to go is as FRM has explained, and personally think the oil is the better lubricant than the grease, as long as I can keep the damn stuff in there.

Thanks Malc
M Brady

Malc -
Yes. Be careful about cutting slots in the bush, as if you overdo this the bush will fall out!

As stated, I have not seen inside one of these racks, so don't know if the design is such that there is a good way to drill around the bush. I'd probable grind or file a flat on the rack, corresponding to the flat where the teeth are cut.

Pinion are usually sealed with a felt ring or O-ring in a groove in the housing.

The inner tie rod ends are lubricated by the oil as it gets pumped back and forth by normal use.

I've had the problem on an MGA I built. It once got serviced in a shop where they pumped the OE rack full of grease. I was very familiar with the car and one frosty morning set off briskly, only to find that the steering no longer returned after a tight fast turn. Way too exciting!!

As a general rule, I've encountered all sorts of "lubricated for life" things that come with no grease whatsoever in them, and no easy or automatic way to add any. Sealed Ball bearings, gearboxes, ball joints, tie rod ends, etc. Third World power tools are really bad on this.

FR Millmore

To the question of racks: How can you tell what type of rack you have? I bought a new rack for my MGB in 1988 when I first had to get it through the TÜV (German MoT). The adjustment has always been fine.

I have just changed the boots and was surprised to find a fair amount of grease in the rack. I always thought it was a NOS rack but now I'm not so sure. I had added oil in the past. I have removed a blob of sticky grease-oil-coagulation and refilled the rack with oil. I also get this pumping effect. I assumed it was normal.


FRM: "Lubricated for life" is more like "lubricated for death". It seems like there's a fair amount of equipment which really is designed to fail when it's just out of warranty.
Mike Standring

My rack had a white sticker,( MGB Made in Argentina) stuck to it, that was the giveaway.
The way of identifying original racks and the Argentine racks,is that the original racks use shims to adjust the pinion and rack, via the damper
Where the steering pinion shaft enters the rack you will see a plate,that has two bolts,bolting it to the rack assembly.
This plate will have a slotted screw and lock nut in the middle, if your rack has this it is probably the Argentine rack, and if your rack does not have this screw and lock nut in the middle,it is probably the O.E.item,
I do like the way adjustment is accomplished on the Argentine rack, which is very easy, and many people swear by these racks,and there are people that swear at them, if you get my drift,
Personally speaking if I had to replace this rack, I would go for the original one, but seeing that my rack seems to be working well apart from the problems I posted originally, I will try to maintain it the best way I can and make the appropriate modifications as suggested by FR Millmore as I think he hit the nail on the head.
M Brady

This thread was discussed between 14/02/2012 and 19/02/2012

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