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MG Midget and Sprite Technical - Surely not!

The bump steer in my 1500 midget has been getting steadily worse.

Track rod ends, steering rack and column etc all seem to be ok.

I found fore and aft play of about 1mm in the shocker arm as it enters the shock body. I took it off to see if there was any way of taking up the play. When it was off, I could rock the stub axle assembly back and forth in line with the direction of travel of the car. I know it should be able to swing in and out at right angles to the direction of travel but surely there should be no movement fore and aft.

Do I have a badly worn king pin/fulcrum pin or wishbone bush?

I'm disappointed in my MOT guy. The car passed just a month ago! I don't mind him missing trivialities but this looks like serious wear to me.

Allan
Allan ('76 Midget 1500)

I've just stripped the other side and, as I thought, no fore/aft play.

Allan
Allan ('76 Midget 1500)

Can anyone suggest what's stopping me from lifting the stub axle assembly off of the kingpin?

I've removed the trunnion, thrust washer and shim. I can lift the stub axle assembly up about an inch then there is a clonk as it comes up against something solid. I can spin it around but can't lift it any higher. From the drawings in the Moss catalogue it looks like the kingpin is stepped thinner towards the top so nothing should stop the stub axle lifting off.

Any ideas??

Allan
Allan ('76 Midget 1500)

Hey allen,

I went to a shock tech session a few weeks back, and was surprised to learn that those shafts are just pressed fitted in the bolt with the cotter pin really does nothing except to postion the arm in the correct position...that shaft may have pulled out of its socket....unfortantly, im a fraid your looking at a new shock or at least a rebuild.

there is a thread currently ongoing on the midget genral sect. titled "Front shockers frogeye" that will be on much use to you.

good luck

prop
Prop

HMMMM
What a refreshing change. Normally members of this BBS moan when the MOT man fails their car for play in the king pin/front suspension! you are the first to my knowledge of someone not happy when their car has passed with play in the front. :-)

Anyway if I understand your description corectly I can understand why the MOT tester failed to find it.

You appear to have a shot bottom fulcrum and a seriously faulty Shocker. With a good shocker even with the problem of the bottom fulcrum you would not feel the play too easily.

Regarding removing the stub axle assembly it should just lift off, perhaps it is hitting a wear point somewhere on the pin, Anyway I can not see a reason why it would not come up.
Bob (robert) Midget Turbo

Allan,

Have you removed the disc and hub from the stubaxle. IIRC the bottom of the kingpin fouls the disc when you lift the stubaxle up preventing removal unless you have already removed the disc and hub.
David Billington

david is correct about the disc and hub, IIRC...

BUT.....If the disc and hub have been removed, and still cant get the king pin to remove...Ill bet the ocsalatiing shock has caused the king pin to create an offset grove/ lip and is now locked the king pin into postion and being held by the offset of the grove/lip


prop
Prop

Thanks for the replies guys,

Doh! I have been trying to remove the stub axle with the disc and hub in place.

I will do the standard punishment exercise of twenty lines:-

I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
I must read my Haynes manual properly.
Allan ('76 Midget 1500)

Alan -- another mistake on your part, the punishment is 200 times, and by hand CUTTING AND PASTING NOT ACCEPTED!! lol
Mick - I have started painting!!!

>>> Do I have a badly worn king pin/fulcrum pin or wishbone bush? <<<

I have a bit of wear in my fulcrums as well, noticed when I was replacing my shocks. I could also rock my kingpins forward and back a little bit.

But since a front-end rebuild won't be possible for a while ($$$$$, or lack of same), I just reassembled everything and I grease all the points at the beginning of each driving season. The car handles fine, with no hint of slop in the front end. I do want to rebuild those areas eventually, but if I do, I'll probably just get the full rebuild kit - the one with new wishbones and everything - rather than try to piecemeal it.

Best of luck,

-:G:-
Gryf Ketcherside

IIRC, the dust shield needs to be removed before the swivel will come off the kingpin. Of course, in order to do that, you have to remove the hub.
David "pedantic" Lieb
David Lieb

I managed to get the stub axle off eventually, strangely enough after removing the hub. I also noticed that there was only one cork washer and no 'O' ring on the bottom dust shield.

I've been trying to get my head round how it all works. It seems odd to me that the kingpin is locked to the fulcrum with a cotter pin. I always thought that the kingpin rotated around the fulcrum pin and the fulcrum pin was anchored to the wishbone (sounds like the basis for an amusing song!).

Does that mean that any rotation in the bottom joint due to up/down movement of the suspension is catered for by the fulcrum pin turning in it's threads?

Allan
Allan ('76 Midget 1500)

I replaced the castle nut with a nyloc nut, when I rebuilt my front end.

The 2nd time (and last) I rebuilt the front end shortly after the 1st time,,,I didnt get the shim thickness correct, and it wore out the O-ring and cork washer fairly fast... that was 4 years ago...no problm sence...just a spot with the grease gun every 3 months

prop
Prop

Allan,

The stub axle rotates about the kingpin when you operate the rack left-right, the kingpin is locked to the fulcrum pin with the cotter, and the fulcrum pin rotates in the wishbone as the suspension travels up and down. Each one handles a different axis of rotation.

<<Does that mean that any rotation in the bottom joint due to up/down movement of the suspension is catered for by the fulcrum pin turning in it's threads?>>

Yes

David Billington

As I understand it Allan, the "Threadform" on the fulcrum pin gives a larger area for the bearing surface. We may even be naughty people for thinking it's a thread at all.

Because of this the base section of the kingpin with its dinky little cotter pin can actually move slightly sideways (either direction depending on whether it's a'going up or down) which is why the dust shield washers are made of pliable cork rather than solid nylon

Or so I have believed for centuries

any minute now someone is going to come along and tell me that I got it wrong again

I love it when that happens

:-)
Bill

Ya got it all wrong again, Bill!

I just couldn't bring myself to disappoint you, although I agree with your position. Think of how much more surface area the "threads" provide in comparison to the kingpin arrangement on the MGB!
David "double zerks" Lieb
David Lieb

Gee thanks Dave
Bill

This thread was discussed between 13/07/2008 and 15/07/2008

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