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MG Midget and Sprite Technical - Front suspension pivot bracket
|The picture attached show the front right hand side rear most front suspension pivot bracket.
This is what was revealed when having removed a thick
layer of greasy dirt.
Not only the small hole is damaged, but allso the big hole lacks approx. 2mm in the lower part.
So together with a very worn joint between the stub axle and the wishbone A-pan it's no wonder I wasn't impressed by the handling during my first season as a midget owner.
My question is if any of you know the dimension of the small hole for the PIN & WASHER, inner wishbone pivot. Is it a tight fit with the pin, I think it's 3/8", the thread is.
|Mmmm... I'm wondering if that's someone else's bodge job repairs|
I want to say there is a rubber bushing that goes in the small hole that should be the same size as the other side
|The large hole fits the inner fulcrum bolt. The diameter of the large part is 1.260. The hole will be a few thous. bigger. The inner fulcrum bolt fits into the small hole which is .500. The bolt then steps down to 3/8 inch. This is a critical part of your front alinement. There are rectangular holes that the inner fulcrum bolt fits into and on the small hole side the inner fulcrum bolt washer. Look on Moss for a diagram. This is going to require some careful welding and grinding to return the holes to the correct size. You have enough of the original hole on each side to make the repair. The area will have to be degreased and all paint removed. The hard part will be getting the car to a welder or the expense of having a welder come to you. You could drive it in as is condition but I would never be a passenger. Good luck. John|
|Don't look on Moss for a diagram, as it's wrong. |
The bolt goes through the small hole. The stepped washer fits into the big hole.
People have been known to fit them the wrong way round, which may be what has happened to your car.
|Dave O'Neill 2|
|As Dave says, the bolt goes into the small hole, but there should be a slot for the tang on the bolt head to fit into.|
I am no stress engineer, but my understanding is that the large washer end takes all the strain, that is why it is a tight fit, and also why the large washer is on the outside of the wishbone in all cases.
I would have thought that the small hole could be welded, as you have 3/4 of it there to give you a guide, and as I said, I don't believe the small hole size is that critical.
|The welding around that flange of the pivot point looks particularly nasty. The other doesn't look as bad. And why is the lower edge profile different like that. Has this bit already been replaced once before?|
|I'm wondering why the small hole has elongated downwards (instead of upwards). It's almost extraordinary. You'd think that the weight of the car would always be bearing on top of the bolt. Or am I missing something?|
|The weight of the car is taken on the spring. If the car rides over a bump, the outer end of the wishbone goes up, the spring acts as a pivot and then inner pin is forced downwards?|
|Does that look like wear to you?|
|Nick and Cherry Scoop|
|No it doesn't Nick, does it! |
It doesn't look quite like rusting out either - the edges are too well defined. It looks more like someone has attempted to rebuild that bit with weld, has failed to fuse the metal and the bit has torn out. The other welds around that bracket look wrong too, with lack of penetration. Also, why is the paint part blue and part green?
|I think it could be wear, if the pin had been fitted back to front.|
|Dave O'Neill 2|
|If you elect to weld the damaged areas to get a snug fit be mindful of the rectangular slotted locations. I thought I'd be clever and make these an interference fit, adding weld to the big washers. Not a great idea - the bushes squeaked. I think these slots are intentionally made oversized so the inner pivots can self align. You'd probably need to measure a Heritage shell to be sure, but it looks pretty generous on this image.
|You have 3 others on your car that you could measure up|
Just weld it up and finish it off to the same size as one of the others------------
|The car obvious has been blue once.
What has happened over the past 47 years we can only guess, but what I disassembled here, I think, was a mix of bad work, wear and maybe rust too in one of the 1/2" holes.
One of my working collegues, a Sprite 1961 owner actually, inspected it yesterday. The small holes on the other side of the car is worn to large too and the brackets are forced out of shape too, not as much as they were on the right side though.
The picture of it was taken after I reshaped the very bend brackets.
The plan now is that we will cut the bad pivot brackets off and weld new ones on again, all four. I have ordered new brackets today.
My buddy will use only the triangular sections of the brackets, since he consider it would be quite a fumbling job to cut the brackets of in one piece.
He will make an alignment tool to fit in the A-arm pivots, and he suggest to cut one triangle at a time off and weld a new one on again.
I'm quite lucky that I know him, he has made many, many cars during the years, a very big part of them being MG's.
He will bring the nescessary tools to my workshop and we will succeed for sure, but it's not excactly what I expected, since the rest of the car's structure is in quite good shape.
on classic cars I can't remember the last time I've heard or seen "That was less work that I expected." To avoid disappointment expect worst then if it isn't you're better off than expected.
This thread was discussed between 05/02/2018 and 08/02/2018
This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.