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MG MGB Technical - Argentinian Steering Racks.
|I have one of "those" replacement Argentinian racks on my 76 Rubber Bumper GT and quite frankly the steering is absolutely awful.|
I have the rack alignment checked twice and it is still unacceptably stiff, and only just about self centres and the steering is incredibly heavy and spoils the whole driving experience.
I know that there are shims which tension the rack to pinion clearance, has anyone resolved the problem by adjusting the shimming and is it a thinner or thicker shim which achieves this?
I have a new refurbed crossmember with Moss coil over suspension with the B&G castor reduction kit ready to fit, but would like to cure the rack problem prior to installation so to achieve a proper solution to the problem.
|Kevin, I have never had the need to purchase a replacement rack. However, you are not the first person to complain about the replacement ones. It would be interesting to know a little more about what was wrong with the original one and the extent to which they can be repaired. |
In the past I have changed the pinion oil seal, adjusted the mesh pressure shims and changed the track rod ends and gaitors.
I assume the bush in the housing is replacable. Has anyone ever changed them? Does it need reaming?
The factory workshop manual shows the seats for the innner ball joints as being a seperate part. Has anyone ever cured slackness there by changing the seats? Do these joints suffer from wear?
It should be possible to change the pinion bush and bearing, but I have never had a rack where there was identifiable wear to these parts.
Would I be correct in thinking that it is wear to the pinion and rack themselves that will put a rack beyond repair. These are major parts and none of the suppliers, with online catalogues, seem to have these parts available.
| I have heard but not seen that some Argentine racks were cast or machined wrong. The angle that the steering column comes out of the rack may be the problem. Check the angle and rack alignment while installing. They have been used by the HOT-ROD set and apparently worked well. I have one but have not installed it yet. It appears to work smoothly by hand,|
|Wow thats a quick reponse,|
The rack is new and has only done about 500 miles, the problem is that the steering is just too stiff and I was wondering if adjusting the internal shimming would improve matters.
The original rack was failed on MOT for wear in the ball joints on the rack ends. in my innocence I thought buying a new rack would solve the problem.
Apparently the Argentinian racks although similar in appearance to the originals, have no exchangeable parts in them.
The rack is correctly aligned and has been filled with the correct oil so neither of those is the problem.
This is apparently a common problem and mine is about average,apparently some are much worse and must be quite dangerous to drive.
Please please, re any suggestions adjustment would be most gratefully received.
|Have you tried going back to your supplier?|
Yes this is the second rack, the first was much worse.
Thew Argentinian racks are the only ones available from any of the MG parts suppliers so no point in trying another source.
My main question still is can the internal shimming be adjusted to reduce the pressure of the rack on the pinion and if so what is the best way to do it?
|Kevin to answer your question, the shimming can be adjusted. Check the steering wheel effort with no load, car off the ground or better still the tie rods disconnects. If the there is little effort required then the shims are OK and your problem is else where.|
If its still tight you could try the shims (loosen the plate and see if it frees up and if it does ADD shims. Good luck. Denis
Just to be clear, if I loosen the cap and that frees up the steering, would I not need a thinner shim or am I missing something?
|You would need a thicker shim or an additional thin shim. I thought those racks were filled with grease. |
|First of all, these racks do not have shims for adjustment, like the original racks do. I bought one a couple of years ago and it was stiff, and had poor self centering. The adjustment is the small screw on top of the rack where the pinion goes in. It is held by a locknut. Loosen the locknut first, then you can turn the small screw. Loosening the small screw will alleviate the problams. It is an experimental thing. Adjust and drive until you are satisfied. Just to let you know, in the end I rebuilt my original rack and it is much nicer.|
|My Argentinian rack improved quite a lot when I filled it with proper 90 oil through the lid covering the pinion. A very slow process. It was only lubricated with grease from the factory.|
Now, after a few thousand miles, I can easily turn the steering wheel from lock to lock with my little finger when the front wheels are off the ground. No stiffness in the system any more.
So you think they may just need the correct lube and bedding in time?
I've looked at the Moss catalogue and see that the shims fit between the cap and the housing body and not inside as I'd thought, so adding a shim reduces pressure on the rack. I don't think mine has an adjustment screw but will check this weekend.
Yes the racks come with grease from the suppliers, but should be filled with gear oil, adding oil to mine did improve it from being undrivable to unacceptable, feels like an old truck at the moment but will try out the suggestion and see what difference it makes. will report back with my findings.
|Kevin - as was said above, to MAKE SURE it's the rack rather than alignment, kingpins or some other cause of stiffness, quickly jack the car up in the front (so the weight is off the front wheels). Then, disconnect each steering arm from the kingpins. Two large bolts each side hold the steering arms on, and are easier to remove than separating the ball joints or unscrewing the tie-rod ends.|
Hop back in the car - you SHOULD now be able to turn the steering wheel easily with just your little finger from lock to lock. If so, your problem is NOT with the rack.
|"So you think they may just need the correct lube and bedding in time?"|
Yes, if everything is correctly aligned, of course. I believe the worst stiffness will wear off quite quickly. Then there is a (too) long period when the self centering slowly returns to what it should be.
|FWIW, I bought one of the first of the Argentinian racks several years ago and have had NO problems with it from installation until now. But that is just my luck. |
My guess is that if there are frequent problems with stiff steering on these units that it is a matter of improper adjustment from the factory (who knows what their quality control is?). If that is the case, Emmanuel's comments should take care of your stiffness.
|I would point out that the mesh of the gears is controlled by the rack bushes and the pinion bearings. The adjustment is simply a friction damper on the rack, and should have no effect whatsoever on gear mesh. If it does, one or both sets of bushes (or the parts they locate) is too loose. I would check the fit and preload of the pinion in its bearings, and then the fit of the rack in the bushes, and check for burrs on gear teeth. Then assemble without the damper. It should be free but not sloppy, then you fit the damper, and make sure it still is so. Burrs on the teeth are about the only thing that you can change, and the only thing that will loosen up in a fairly short period.|
|Thanks for the further comments.|
I found in the archives about a year back, a thread re the Argentinian racks which i contributed to and forgotten about,that there was a posting by Kelvin Dodd (Moss USA) that they had found that the early racks from Argentinia were coming in with too much pre load on them. I'm going to try adjusting this first because I know the king pins are ok and the rack alignment should be ok because it was checked not long ago.
Will report back with results this weekend in between being glued to the box watching the Melbourne Grand Prix which should proove to be an exciting start to the season.
I found that the rack i have has the screw and lock nut in the cap to adjust the damping. I loosened it off one full turn and it has made a small improvement but nowhere near being acceptable. I will double check that the king pins are turning freely and also re-check the rack alignment but I will be surprised if that makes a difference as I'm fairly sure the problem is with the rack. I dug out my old rack and it turns from lock to lock as smooth as silk just by turning the pinion shaft with no play whatsoever. It failed an MOT on wear on the outer joints but i can't feel any play in them.
I going to take the old rack to a specialist to have them check it out, and if there is any wear, see if they can fix it, although I believe there are no spares from the usual MG sources, they may be able to find parts that will fit.
I'll let you know how I get on.
|Took the old rack into the steering rack specialist today, and they did a quick strip down and confirmed that any wear was well within tolerances.|
They are going to rebuild the rack for me and reset the pre-load, fit new gaiters and repaint all in for £50.00 which considering the grief I have had with the new rack and an over zealous MOT man, doesn't seem too bad.
I will now arrange to have my coil over front end with castor reduction kit fitted, fit and align the rebuilt rack at the same time, hopefully I should have greatly improved and lighter steering, probably won't happen for about a month because I'm currently fitting new trim and a set of leather seats I picked up off e-bay for £180.00 but looking forward to a much better driving experience.
Will report further when it's all fitted.
75 GTV8 Conversion
|Kevin, I believe you will be much happier with your rebuilt original rack. I know that I have been ever since I rebuilt mine and got rid of the Argentine rack. I got my Argentine rack to be acceptable, but the original is better.|
This thread was discussed between 12/03/2007 and 21/03/2007
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