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MG Midget and Sprite Technical - Can't fit trunnion

I'm rebuilding the front of the new car. I can't get the lever arm to line up with the trunnion by some way. Have i got something wrong or could the arm be bent?? (it's a Peter May unit so I suspect the former and I had a glass of wine or 2 before i went to the garage) Advice much appreciated before I tackle the other side.


John Collinson

That looks to me like a lower pan alignment problem to me. Are the pins and bushes in correctly?

Check when Sober...!

Mark.
Mark T. Boldry

You HAVE one of 2 things reversed....not sure which is the front of the car.....

shocks are reversed (on the wrong side of car) or the pans are reversed...cant remember if the pans are reversable or not


but thats my take


prop
Prop

I had a similar problem (though not as bad) I was able to correct it by narrowing the tabs on the inner A-arm pins. It seems they were to wide to properly set in the slots and thereby allowed the bushings to be misaligned.
Trevor-Jessie

The wishbone, a-frame, or what ever one would call it is interchangeable side to side. The picture looks like it is the left side. If so the shock is correct. Are the trunnions symetricial?
J Bubela

I think the A-arms are symmetrical... also, the shocks can only be mounted one way.

Good question! I can't think of any reason for those parts not to line up.

-:G:-
Gryf Ketcherside

Your A-arm wouldn't perchance be twisted, would it?

Grasping at straws,

-:G:-
Gryf Ketcherside

Where did the shell come from?

I had one the same where originally the shocker mount had been welded on incorrectly positioned. It was a heritage shell.
Bob (robert) Midget Turbo

Looks to me like you have the stub axle on the wrong side,
Noel Copping

Since the wishbone and axles are interchangeable, side to side I would swap those with your other set. This will at least eliminate or narrow down the problem.

Maybe your problem is the bottom fulcrum pin isn't worn out enough to allow the kingpin to tilt backwards?
Guy Weller

Which car is it, John? I don't recognise anything.
Nick

The pic is of the left hand (UK car) side. I did the other side after a cup of tea - pic below - and that all went on brilliantly - just a couple of shims needed under the top link and all slid together. Therefore nothing is reversed. I'll check pan alignment and everything else again tonight. The bushes (all nylatron) went in relatively easy, but may have become dislodged I supposed before i tightened things up.
The shell is a completely rebuilt early 1/4 eliptic so not Heritage, although most of the panels have been replaced.


John Collinson

John,
The stubaxle and surface where the oil seal runs look rather rusty in that picture.
David Billington

Looks like a misaligned shell to me (didn't the early heritage shells have this EXACT problem?), but have you tried slackening all the various bolts off? as everything will be acting as a long lever it might be possible to muster up quite a bit of adjustment. What all this will do to your suspension geometery I wouldn't like to comment.

p.s. where have your inner wings gone?!
Nick

Accident damage can result in a twisted lower wishbone, (which is easy to untwist for the matter).
Is the shock new or recond? The arms on those bend as well. I'd suggest that beofre you go stripping the suspension, do some careful measuring to establish where the problem is:

Set up the shell so the sills are level and the car is level side to side.

Measure the distance from the rear wheel rim (or any other reference point on the rear axle) to the centre of the wishbone on each side and compare.

Ditto to the shock arm. Use a spirit level or plumb line at the rear to extend your reference point into a vertical line rather than just eyeball.

If these all measure to be the same, measure the kingpin castor against a spirit level (no need to do degrees, for this comparison a difference between top and bottom of the kingpin will do.) If this is different, the wishbone is twisted.

Somewhere in the above measurements you should find your answer. Doing so makes it easy to target the rogue component when you strip it.
Paul Walbran

Yes, stub axle needs a clean up but looks worse than it is.
Have ditched the inner wings - lighter and easier to get at everything. This is my racer for next season.

Have had a thought - if the additional top link fits to the side of the trunnion and the original arm doesn't, then it must be a bent arm rather than a chassis issue. Does this make logical sense?
John Collinson

Why not drop the n/s shock off your other car and check again, at least you'll know if it's the chassis or not

cheers
Neil
Neil Williams

Normally there is a little play in the threaded fulcrum so that the kingpin top can be aligned with the damper arm...

A
Anthony

I dont think its the shock arm...because the rubber bump stop aligns perfectly under shock lever arm...

IMHO... if the perch was twisted for truoin to be that far off,,,,it seems the damage would be evident with the eyeball....

Im woundering if "Anthony, Malvern" may have nailed it and the fulcrom pin was inserted (built) wrong or is way out of adjustment...beyound that, Im stumped.

Id find a common referance point on both sides and measure the horizontal distance from the center of the axle to your common referance point on both sides of the car and compare....Much in the same vain as "Paul Walbran" porposed.

prop
Pro P

HA and HA......

I FIGURED IT OUT>.......oh so simple....as they say look for the simplist and stupdist first...but wow, that is hard to see.....

what is it.....you got 2 right side pans (or the wrong pan,,,diffreant model car)....notice the 3 anti roll bar holes on the front of the pan on the side that went togather correctly....they aint there where they should be on the side thats not happening....


Oh yes, OH YES ....I DO love those pats on the back!!! the swelling of the head has truly begun....just in time for spridget 50....LOL.

prop
Pro P

Sorry, Prop there are holes front and back. The pans can go on either side.

Trevor-Jessie

Must be the wrong pan!!! ... anti roll bar holes are not there AND there is a lip ledge along the bottom edge thats not there in the other photo as well...."clearly" the front edge of the 2 pans are NOT the same.

prop
Prop

John, I ran into a similar problem years ago rebuilding the front of a friends Frog. Using refurbished pans on one side the trunion came out slightly out of alignment with the shock arm. I believe that either the pan was bent or twisted, or that the lower trunion bushings had been installed out of alignment. The only other thing I could think of is that the kingpin is damaged and not true to the bore of the lower trunion. Are you using refurbished kingpin assemblies as well?
Bill Young

The odd thing is that in the photo, the lever arm for the off-side looks as if it is dead straight, without the two bends in it. I guess that is just the angle of the photo because it should have bends.

As for the nearside, although I said it in a jokey way, there should be some slack in the bottom fulcrum pin to allow it to lean backwards slightly to give the correct castor angle.

I also think that the lower pans are not that stiff and should twist to allow the pin to lean backwards. So, if you slacken off the damper mounting bolts it may be possible to pull the trunnion into position, load the suspension and then tighten everything up. Come to think of it, you shouldn't have tightened up the inner wishbone pivot pins before loading the suspension anyway.

I think Nick had it earlier when he said try slackening everything off first, and then see if the trunion will fit.

Guy
Guy Weller

Panic over. It is the damper arm that is bent. The additional top link fitted the trunnion fine so I dug out an old lever just to check and that was no problem. Can't see the bend with the naked eye though, so i will be back in the post to Peter May tomorrow - first timeI have ever had issues with their stuff though.
The wishbones btw are from the guy selling them at Gaydon - the "uprated" versions which look really good. Thanks for all the comments.
John Collinson

Well Obviously, That was going to be my NEXT consideation,,,If the pan thing didnt work out.....So see Im still right....LOL


glad you found the problem....what a fun challange that was.

prop
Prop

A laptop, camera and connection to this bbs should be a part of an essential spridget toolkit!
John Collinson

John

Have you got the inner fulcrum pins fitted the wrong way round? Both sides.

They only fit one way and I'm sure they aren't right.

I'm away at the moment, so have no car or books to check.

You will have very wayward wishbones if you have!
Dave O'Neill 2

Joihn I am sure Dave has it right

My new pins are tightened from the back end at the bck and the front end at the front, so the nuts cant be seen where yours are, only the "bolthead"

And that was the way they came out (eventually after god knows how much grief)

the pivot pin lockwasher has a locating "extra big washer" that sits in the hole at the open end of the setup doesnt it

that locates the unit at the proper place then when you bolt it all up

Bill

Dave/Bill,
Many thanks for the heads up. Simple answer is I'm not sure! I have not done this before, so it is all a big learning curve. I thought the pins only could go in one way, but i'll have another look tonight and take the Haynes with me.
John Collinson

Funny how you can't remember, despite having built it less than a year ago, isn't it? The back end nut should definitely be at the back. But I thought the front end nut was also at the back.

I shall have to look now.

Good spot, Dave.
Nick

I don't think it makes a difference to the wishbone alignment, but there is a right and a wrong way. The large, loose stepped washer always goes into the large mounting hole. So the pin inserts through the small mounting hole first.

This means that the front one inserts pointing forwards, with the stepped washer and nut on the front end. This makes it easier to remove when the time comes because you can align a drift with the end of the pin and tap it out towards the rear.

Conversely, the rear one inserts from the front, pointing rearwards. Thus making it posible to drift it out from under the car - though not quite so easily.

I always felt that the idea of relying on the larger stepped washer to stay located accurately in the larger hole in the chassis bracket was a bit wishful thinking. The brackets are very thin and easily distort so that the thin step in the washer never seems that firmly positioned. An odd arrangement!

Guy
Guy Weller

The large washer-ey bit acts to centralise the whole bl**dy issue so it is actually very important in the scheme of things.

I became mentally scarred trying to separate them when I went polybush/autobush this spring

So I knew there was summat wrong when I looked at the picture, it just didn't hit me what it was.

It is definitely nut at the front, at the front. And nut at the back at the back.
Bill

yep Guy and Bill's latest are correct, just checked against my car.
David Smith

Yes - so they are (I checked too).

When I was rebuilding - scraping, straightening, painting - I was surprised at how bendy everything was in that area. I had to do some careful work to get everything straight, so that the pivot pin lockwasher with the "extra big washer that sits in the hole" was nicely located all round.
Nick

Mine are also "nuts to the outside"

http://www.eatworms.org.uk/album/album2.php?album=midget-FrontSuspension&mode=page&index=12

Very good spot !
Dean Smith ('73 RWA)

Thanks guys - out with the spanners then!!
John Collinson

As I said, the reason is fairly obvious. It would be quite awkward to get sufficient access to drift them out if they are fitted the wrong way around. Inserted from the insides of the wishbone means that they can more easily be drifted back the way they came.

Guy
Guy Weller

easily!

"hey everybody, that bloke up in Cumbria said easily to Mr Birkenshaw"

I had to hack the blooming boltheads off the bolts with a nanglegrinder because they were all rusted into the sleeves. So then I could get them out of the BIG holes.

"Easily! You were lucky, we lived in a hole in the grou........."

Sorry

wildly Python moment there

But I wish I had been that lucky
Bill

This thread was discussed between 22/06/2008 and 25/06/2008

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