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MG MGB Technical - Steering Wheel judder

My '78 gt is susceptable to steering wheel judder when running over rough surfaces. Advice welcome perhaps worn king pins or play in the steering rack may lead to the juddering? could there be any other contributing factors.
si robathan

Worn steering column bushes.
Dave O'Neill 2

si. Dave has one answer. But, it is only one answer and may not accurately reflect what you are feeling. I had a similar problem with my 68 GT and the answer was, in that case, the universal joint linking the steering column and the shaft of the steering box. This U joint does not have a zerk (grease fitting) associated with it, thus it is never lubricated. After 31 years (the last of the MGBs made), many of these U joints are beginning to show some wear--at least on the cars which have been regularly driven over the years.

The first place that some form of "judder" can start is the mounting of the cross member to the frame--the rubber pads deteriorate over the many years and the cross member becomes loose. Then, there are, as you note, the king pins, the stub axles, wheel bearings, and tie rod ends. And, do not forget that a worn hydraulic dampener (shock absorber), or one which has become loose on its mounting tower, can induce some judder which will be felt in the steering wheel.

Start by tightening the cross member the frame, then move on through the system checking to see which parts are still tight and which may have loosened up over the years. Cross member, steering rack, dampeners, in that order, will then allow you to begin to check out the other parts of the system to see which might be less than optimal. End up with the steering wheel, ensuring the nut holding it onto the steering column is tight.

Les
Les Bengtson

Adding to what Les said,you may find it necessary to jack the front corners up at different places to check different things. Grasping the wheel at 1/4 to 3 and 6 o'clock tends to show play. For track rod ends the weight of the car needs to be on the wheels. Under the spring pan for kinpins bearings top and bottom joints and security of the damper mounts. (bearing play -some is necessary- can be shown if the play is eliminated when you apply the brakes). Under the central crossmember may show play in the inner mounts.
Michael Beswick

The steering column UJ - and many other parts - *should* be an MOT failure in the UK if they are exhibiting play, but it's not guaranteed, and there can be other sources of wear. The first step is to move the steering wheel up and down at a standstill to check the upper bearing, next lightly rotate the wheel back and fore, short of turning the wheels, and see what free-play or noise that generates (needs one to turn and one to look/feel).
PaulH Solihull

Maybe Si could define 'shudder' more clearly?
John Bilham

Gentlemen, all very sound comments. What a clever lot we are! If we were a team in politics, I bet we could sort things out! However back to the shudder through the steering. I also had this shudder, most characteristically while going over rough roads, or a pot hole. I do have some play in the steering outer to inner tube, and being a chrome bumper no collapsible column so I will attend to the bushes. But my recent full front suspension overhaul allowed me to examine other areas. The king pins did show quite some wear so overhauled units have gone in. I noted that I could detect the play by hand, the new units turn nicely, but absolutely no other play. The steering ball joints seem very good no detectable play. The A frame bearings rubber, yes, gone hard and play detectable. The upper swivel joint, where it afixed to the lever shock, well one side was rubber, the other urathane. Some PO had only renewed and updated one side. The car is a 38 year old chrome bumber. So if your car is similar in age, I would supect all these areas may be tired. I found the subframe to chassis rails ok, rubber may be hard, but no gap or play. It is not a hard job to renew all, bit fiddly, but a nice project. Currently I am waiting on some new track rod ends and rubber gaiters (old were shot.) The steering rack while off the car was tested for play and notchyness, perfect, so it will go back on. all the best Mike
J.M. Doust

Just to add to my last comment; Why do we have to aling the inner steering column with the racks' mast if we have between them a universal Joint? Plenty of front wheel cars today have a universal joint transmitting steering wheel action to the rack and in no way are the parts aligned? One might even say on the MGB if both the column and mast are so well aligned, why not connect them with a hollow tube with a pinch bolt at each end ( It would have to be stout I know, and not able to slip. )But do you follow me? Is the alignment purely so as not to make the steering heavy? Mike
J.M. Doust

The geometry of the common u joint requires that the centerlines of the shafts intersect at the centerpoint of the UJ. A lot of this is built into the parts, but the centerlines of the shafts must in fact intersect. That's what you are adjusting. Some WSM have a picture of the setup and the tool 18G1140, which should make it clear, but others just give a verbal description. Most FWD cars have two UJ, so the center shaft is self-aligning.

FRM
FR Millmore

Also with the later energy absorbing column you have to get the up and down alignment of the whole column correct as well as the side to side and up and down of the UJ end, as the inner is 'fixed' in relation to the outer in that dimension. With the earlier solid inner columns the inner moves up and down the outer at will, so automatically takes up the correct position. Incorrect alignment, particularly up and down and side to side, causes rapid UJ and rack pinion bearing wear and can cause breakage. The column and rack shafts are significantly *un*aligned, hence the need for a UJ rather than a rigid tube, which articulates as the steering is turned.
PaulH Solihull

Thanks for that last comment. I have 'Turned up' on the lathe a couple of alignment guides. Mike
J.M. Doust

This thread was discussed between 26/08/2011 and 04/09/2011

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