MG-Cars.net

Welcome to our resource for MG Car Information.

Recommendations

Parts

MG parts spares and accessories are available for MG T Series (TA, MG TB, MG TC, MG TD, MG TF), Magnette, MGA, Twin cam, MGB, MGBGT, MGC, MGC GT, MG Midget, Sprite and other MG models from British car spares company LBCarCo.

MG Midget and Sprite Technical - Lower wishbone issues

One thing that has long irritated me is that one of the weakness of these cars is that you cannot easily rebush the lower wishbone (you know, on the kingpin end). It is weilded on or something. these seem to wear out over time. I try to grease this up once or twice a year (or every oil change, I dont drive more than 3000 miles a year typically). The welch plug on one pupped off so I havent been able to properly grease that for some time and I couldt fit a new welch plug because moss doesnt sell the right part etc. Anyhow, its time to replace these again because of the worn threaded bushings. I hate having to shell out 400 bucks for an aftermarket set, or 600 bucks for a pair of BMH ones from moss. Can the home mechanic rebush these by any chance?
S.A. Jones

SA.

They have been re-bushed in the past but you are still on an uphill struggle.

Contact Barry King here in the UK, his Dad makes the wishbones and Barry sells them for him, I'm sure they supply to Moss and the likes.

They also do an uprated pan with modified lubrication for the fulcrum pin.....

Chat to Barry on +44 (0) 7774 729369

Mark.
Mark T. Boldry

SA,

At times people in the US and UK have sold pre-threaded bushes to braze into the wishbone once the old ones have been removed, I've seen them on ebay in the past. Not ideal but it works. You have to insert an old trunnion pin into the new bushes to ensure alignment of the threads as the helixes must be coincident.

I have been told the correct method, or best anyway, is to braze in plain bushes and use a special tap to cut both threads at the same time and make sure they're coincident. The tap is available IIRC, but costly.
David Billington

David b, do you know by any chance where one would get those plain bushes and the special tap? I may be able to convince the club to add it to their tool chest
S.A. Jones

SA,

I've seen the prethreaded bushes on ebay but never the plain bushes, the tap I think has been available from some of the usual specialist suppliers. I was told the way to do it properly by a local guy that used to do them when they were far more common and he did loads. I personally have never looked for either the tap or plain bushes as I modded the standard design in the late 1980s to suit easily replaceable bearings. Easy with the time, machine tools, and welding competence. The way I did it http://www.metal-arts.co.uk/sprite/frontsuspmods/index.html at the bottom of the page.
David Billington

how does tis solution look? http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=320339595680&fromMakeTrack=true&ssPageName=VIP:Watchlink:middle:us
S.A. Jones

I've seen that arrangement before on race cars and a general comment is it is considered bad engineering practice to put threads in bending which those joints will be. It is done successfully on a number of cars, even road cars, but more typically on the much more lightly loaded upper joint. I'd stay away for road use.
David Billington

Also depends on how well the plate is welded to the wishbone. It also makes me wonder about overall strength of a relatively thick (at least that's how it looks) plate welded to sheet steel on the 'pan.

As they say, 'failure here isn't an option'!

A
Anthony Cutler

A friend of mine uses an oilite bush with an unthreaded fulcrum pin. It's still very serviceable after 25,000 miles.
Now if only he can overcome the wishbone's desire to crack.
Mike Allen

Mike,

I've modded my wishbones years ago to take oilites and replaceable trunnion parts as linked above. What has your friend done, what does he do with the car, and where is he suffering cracking. I've put about 65k miles on the wishbones after modding with 185/60 x 13 tyres and no signs of any problems.
David Billington

David
It only gets (very) enthusiastic street use. He lives at the top of a nice winding mountain road.
Pans crack behind the outer fulcrum and near the inners.
Mike Allen

I am starting to REALLY like your solution david, its too bad that your website only has pictures but no instructions. I use 145/80/13 (stock size) and if you have it at 185 with that mileage I really want to try this. I don't know where to source parts, but I know this would make a great tech session in my local club if I could get the parts. I have no idea what an oilite bush is or how this mod is carried out. Oh and the best part for me is that it almost looks stock, and it looks very strong too.
S.A. Jones

Hey SA,

Why not make some tubular A-arms....give me a bit of time But I have some photos somewhere

prop
Prop***The End in 2012

Hey David Billington,

Do you still make those upper link suspension parts, if so how much are you asking for a pair???

I like them vary nice.

Prop
Prop***The End in 2012

Prop. Is this what you meant? Still the same problem with the shear on the lower heim joints. Better to make bronze bushes for the bottom link, in hindsight.

http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=q3

http://www.spritespot.com/gallery/view_photo.php?set_albumName=toomanyspridgets&id=qa2
rob multi-sheds thomas

Rob,

Thats a great looking set-up, more advanced then I was thinking, but yes I like it, Id imagine this set up would be much better then stock by any comparison, even with the built in problems of this modified system, Granted, I dont have a real problem with the stock set-up, I just hit it with the grese gun every 6 months, and its still as good as it was 6 years ago,

BUT if you going to go the hassle of making new modified pans, Id go the extra mile and do a tubeular lower A-frame and a Upper link like david billingtons, and use a good coil over AVO adjustable telescope shock.

I wouldnt recommend hiem joints unless on a true race car for the track, as pointed out you cant go wrong with a good set of bushings.

Prop
Prop***The End in 2012

HEY SA

Try this place, they have the replaceable bushings your looking for, I think they will even install them for you

http://www.spridget.com/catalog/

prop
Prop***The End in 2012

Mike,

Has your friend had a succession of wishbones crack?. Is the suspension particularly stiff, or is the environment prone to cause corrosion, seaside. I'm not aware of wishbones cracking being a common occurrence on road cars so wondering if there is some other factor effecting them.

SA,

I have provided details to people that have asked in the past, last time a couple of months ago to a US guy. The work does require machining of the parts and wishbone and of course welding which has to be of high quality. As mentioned on the website the bottom of the kingpins need to be faced, I used the OE spec ones that are like that but I don't think they have been available since the early 1990s. I do think though that as others have said, the short life you're experiencing must be caused by something as normal life is much higher especially with regular greasing. The ones I modded were 2nd hand when I got them and they saw about 15k miles of use before I altered them and they didn't gte the 1k mile grease often recommended.

Prop,

I only made the one set and haven't any plans to make any more at the moment. With the £ $ exchange rate being in your favour now compared to a few years ago you could buy from FL for about $450 + shipping unless they have some restrictive agreement with US sellers and can't sell directly to the US.
David Billington

David
I don't know if it has been a succession of cracked wishbones on one car or a collection from several cars. And yes, the suspension is quite firm. If there's an underlying cause it's no big deal as the car is soon to be re-shelled.
Mike Allen

15k is once every 5 years at most. Shelling out 600 bucks for new a arms every 5 years is unacceptible. If you could email me the instructions on modification, i do have some spare lower a arms which have worn bushings I could try it on. I also have access to a mig weilder.
S.A. Jones

SA,

I sent you some information I sent to another recently, if you need further information please ask. Regarding the 15k miles I did on the wishbones before modding them, they didn't need doing at the time, I just took the opportunity to change them while doing the upper link assembly and had access to the equipment. Regarding the MIG welder as well as having access to one hopefully you can set it up correctly and run good welds as this work requires them.

BTW what's your first name, it would be nicer than just referring to you as SA.
David Billington

My name is Seth
S.A. Jones

This thread was discussed between 09/02/2009 and 13/02/2009

MG Midget and Sprite Technical index

This thread is from the archive. The Live MG Midget and Sprite Technical BBS is active now.