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MG MGB Technical - Steering rack wear?

How would you measure this? The situation is that I have no play in the steering. When the front wheels are off (or on) the ground they turn freely and smoothly from the steering wheel, but if I turn a road wheel it gives a rough feeling and sound as it moves from lock to lock.

In the event of the rack neeeding changing, does anyone know of a good guide to this job? The Haynes description left me scratching my head a bit.

Thanks,

Steve
Steve Postins

Is there the correct amount of EP90 in the rack? Are the king pins OK ?
S Best

Hi Steve
Mines exactly the same - no real wear visible, no free play in the straight ahead position, no binding in the rack either side of straight ahead after checking the shims.

I put it down to the fact that turning the steering by swinging a road wheel from lock to lock is a lot faster than when you turn the steering by using the steering wheel, and that any rumbles in the rack, universal, and steering column are amplified by this.

WRT servicing a steering box, dismantling and reassembly is pretty self evident. The one thing is that the rack itself must be held in a vice with soft jaws when removing the inner ball joints. Do not hold the rack housing and depend on the pinion gear to stop the rack from rotating.

Cheers
Ian F
Ian Fraser

I'd check out the rack in place first. Pull the left side boot and see if you can wiggle the rack up and down. If so, removing a shim (or two) from under the cover may take up your slack. If having done that you still have too much play, then consider rebuilding or replacing.

In any event make certain you have plenty of EP90 in there.

My "B" has been on the road more or less constantly since it was built in '67. Rack is A-OK.

Mike!
mike!

You may want to bringthe car to an alignment shop. See if they will put the car on the rack for you with the front tires on the "lazy susans." Eliminating the tire scrub might give you a better feel for where the grinding is coming from.
I agree with Mike about checking the shims in the rack. Under the top cover is a brass steering damper than needs to be shimmed to the right tension. Disconnect the tie rods from the spindles and remove shims until you can freely rotate the pinion (steering) shaft by pulling the rack back and forth through its housing. Each time you remove a shim, retorque the cover plate. When you get to the right tension, top off with S.A.E.90, use a good sealing compound on the shims and reassemble. The sealing compound will give you the extra .0005-.003" clearance you should add to the shim thickness, per the Bentley manual.
Jeff Schlemmer

The rumble is from the rack itself, as opposed to the kingpins or wheels, but there is no discernible play or roughness at the wheel so I'll try the suggestions of adding oil before examining the shims.

Thanks
Steve Postins

I don't think you have a problem here at all Steve. In my experience if you move the road wheel from lock to lock with the car jacked up it does sound a bit rough. Remember that the whole assembly is being driven in reverse and is actually moving much quicker than normal. When it gets "motored" in this way it is always noisier and that tends to be amplified by the car body. You say you have no play in the system so as long as it appears well lubricated it should be fine
Iain MacKintosh

I found noticeable improvement with use of Redline 90w in turn effort.
vem myers

BTW , always be careful not to slam the assembly against the stops , you can damage the rack. Mine is original and covered 100K+ miles all it has had is one shim removed and it is as smooth as silk with the front wheels off the deck .
S Best

Roughness could be anywhere, you may have to start disconnecting things (like at the UJ and the track-rod ends) to find out where. Changing the rack is simply a matter of disconnecting the track-rod ends and the UJ, and undoing four bolts.

The first is very glib, the nut and shaft of the track-rod could be well corroded and be difficult to shift.
Resetting the tracking could be problematic as with a new rack you will have lost the points of reference to get back close to what it was before (which may not have ben right anyway). So at the very least count the number of turns you unscrewed the track-rods out of the track-rod ends and screw them back in the same amount as a starting point. A couple of straight-edges across the wheels poking far enough forward should also allow to take measurements and adjust for zero tracking which should be enough to get you to a local tyre place for a proper check.

For the UJ on my cars one shaft (the column I think) has a groove all the way round to allow the UJ to be fitted in any position whereas the other only has a notch and the UJ only fits in one position. The shaft with the groove all the way round will allow you to get the steering wheel and lock back in the same position it was before. You will have to push the rack into approximate position from the front, then get the splines of the UJ aligned and inserted by leaning in over the wing, pulling the rack into its final position as the splines engage. Then refit the four rack bolts.
Paul Hunt

That all seems pretty straightforward and I take the point that all may be normal. The track rods have been undone in the last few months so should be easy. It was the Haynes warnings about alignment and special tools that bothered me with replacement, but I guess that comes clear as you do the job. I'll lube the rack this weekend and see how it feels.

Thanks again
Steve Postins

I had the same thing and found that the rack had been packed with grease. When I replaced grease with EP90 the noise disappeared.
Mark
Mark

Ah, the alignment issue is a good one and relates to replacement of the steering column or rack, or loss of the adjustment of either. If refitting the same rack you should be OK as long as you are careful to note where the shims on the mounting bolts come from and put them back in the same place. However simply removing and replacing the column means that realignemnt is necessary, but it is not as complicated as the books make out even without the proper tool.
Paul Hunt

This thread was discussed between 24/11/2004 and 27/11/2004

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