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MG Midget and Sprite Technical - Poly Bush Fitting

Afternoon
I'm trying to fit the Polybushs on my 1500.
I have got to the point where I'm stuck
I've scoured the archives but still not sure.
I'm replacing with Superpro Blue bushes. I have double checked they are the right ones. They came from moss & the part numbers from Moss & the originator concur. They are also identical in size to the old rubber ones removed.
There are no instructions on the manufacturers website only "general" instructions on the back of the packet.
In the archives the are doubts about fitting the inner sleeve or crush tube.The general instructions state: always use crush tubes & spacers where supplied - so I will use them.
The proble:- I've tried to fit the inner bushes & then"offer" the wishbone into place. No chance of getting it into place. I levered between the face of the bush & housing & the wishbone partially went in & that's as far as it goes. It's absolutely stuck solid & so I have now left it for the day.
I have put the inner sleeve in, should this make any difference? or should the inner sleeve be put in after the wishbone/bush is in place.
The archives talk about putting a paint scraper between the bush & chassis. Given how tight it is ~I find this difficult to see if this would work. I suppose It's more likely to work as looking at the bush as it. is now. The half that's not in is splaying out as it is slightly taperd and therefore nothing is moving.
Tips, help, advice would be very much appreciated
Regards
Nigel
Nigel Axtell

Chamfer the leading edge of the bush - if not already.
Ensure all mating sufaces are clean. It is such a tight fit that it will pick up on any any minor high spot. Suggest emery paper wrapped round a drill bit for the inner surface of the eye. and perhaps take off a small amount from the bush itself - attach the bush to the drill chuck somehow - i.e. clamp a long bolt through the bush - and use 80 wet and dry. For each method don't take off too much! It still needs to be a tight fit. Use the lube supplied or a dab of graphite grease. Use of a G-clamp to pull it in may help. I have always inserted the sleeves after the bush is in place.
Oggers

Nigel, you may be assembling them wrong. Refer back to that previous thread where Dave identified whch way round to assemble the pins and large washer. Done right, you only fit the inner polybush of each pivot leg of the wishbone. Then offer it up into position on the chassis. Insert the pin and then slip the second polybush on through the large hole in each of the chassis brackets. Then add the large stepped washer, align the hooked bit with the slot and tighten the nut up. This will push the polybush into its receiving hole in the lower wishbone.

I think you are reusing your wishbones, so this may not apply to yours. But some/many/most aftermarket wishbones are wrongly made. The holes that the bushes go into should taper inwards from either end, with a slight radius on the ends. The aftermarket ones seem to be mostly made with a short length of paralel sided tubing, so there is no taper and no self-aligning effect. Anamnesis may comment, or add a photo.
GuyW

I concur with Nigel - inner bushes first, A-pan in place, pivot bolts in position, outer bushes through the holes then the centre tube then large washer and nut. I wouldn't want to be cutting or sanding the bushes, they should fit as they are. The only thing I can add is to smear some of the supplied grease on the inner face of the pivot bracket before inserting the A-pan.
David Smith

Thanks for the comments.
Guy, that's exactly what I'm doing as your first paragraph. I only have the inner ones in place to each leg. But the wishbone won't go up into position as it too tight. They are the existing/original wishbones
As you can see from the attached photo, they have a slight taper, so any amount of squeezing them in, they naturally want to pop out.
I'm trying to do it as the sequence David suggests as it is probably the only way it can be done which is why one side of the chassis has a larger hole so the bush can be fitted through the outside.
Not got past the first stage yet!


Nigel Axtell

Nigel, sorry to repeat back to you what you were trying anyway! I misunderstood what you said
The paint stripper trick does work. Thin flat blades positioned between the face of the bracket and the bush then allows the polybush to squash into their holes in the wishbone as the wishbone is pushed against the chassis rail and into place. You can either use 2 and juggle all the various bits, or get one bush in place with the wishbone skewed and then hold the paint stripper blade in position as you push the second pivot bush in towards the chassis.
It may need a bit of lube on the stripper (whoops!) and needs a bit of force!
GuyW

Cheers Guy
I’ve taken them back out. I’ll give it another go with the paint scraper method and see how we go
Regards
Nigel
Nigel Axtell

Can’t really offer any tips on fitting - I remember it was a nightmare though - but one thing you must be sure of is that the large stepped washer is properly located when finished. Years ago when I fitted the blue poly bushes to mine they were so tight that I didn’t get them located properly and they subsequently wore the holes in the chassis.

I ended up replacing with nylatron (much better in my opinion) a few years later and had to weld up and repair the worn holes.
John Payne

When I did it I used a vice to push the inner bushes in a far as possible. I seem to recall my SuperPro were supplied with sachets of silicone lubricant but don't recall whether I used it on the wishbone bushes. I may have used WD40 on the inners but silicone on the outers.
The paint stripper blade should make it easier, well lubricated. If you have some help you could try 2 paint stripper blades.
Rob

MG Moneypit

Nigel
I realise poly is stiffer than rubber but did you put something slippery on the end of the bush and inside of the bracket e.g. fairy liquid or swarfega? It certainly helps with rubber bushes.
Bill Bretherton

Easiest to leave the spacer tube out initially just have the two half bushes in the arm--The spacer tube needs to be left out while pushing the arm up into place-- lube the faces of the bushes with the lube supplied in the kit and poke it up using a blade (paint scraper)to start it in
Then when it's in place lube the sleeve and poke it in through the hole along with the outer bush
William Revit

Afternoon all
I have successfully fitted the bushes to the drivers side - used wallpaper scrapers. Many thanks for the advice & tips.
However, I have come to do the passenger side and discovered a problem which I didn't notice when I removed the old bushes.
Someone has welded the large or what looks like the large washer over the large hole. The condition of the metal is sound and no different to the other wishbone mounting points so I don't know why this has been done. (Someone in an earlier post picked up that they thought the bolts were fitted the wrong way round. What I did also discover is the none of the bolts had the large 'tabbed' washer. As I say, the drivers side is now fitted correctly with the right parts.)
The problem is unlike the other side you can't get the outer bush & inner sleeve in because the hole is too small & only accepts the bolt. Even if you squeezed the two bushes in at the same time you can't put the inner metal/crush tube in afterwards as it won't pass through the holes. The tubes have to be fitted as there would be about 2 - 3mm 'slop' without them.
I was thinking would it be possible to drill out the hole with a step drill, the o/all diameter of the bush is 29 mm.
Screwfix do a step drill bit 3-36mm.
Access is the next problem, my drill won't get in horizontal due to the length of the drill , it looks about 10 - 15 degrees off horizontal. Screwfix do an angled chuck adaptor that would then allow the drill to be horizontal.
Your comments would be greatly appreciated or maybe other solutions
Image 2 shows what the hole should be like - this is the left side of the wishbone (passenger side)
Mant thanks
Regards
Nigel





Nigel Axtell

If you look at the inside of that web, does the large hole (behind the washer) look like it is the right shape?

If so, it would probably be best to grind off the washer and fit the correct parts.
Dave O'Neill 2

Hi Dave
Thanks for the reply.
Yes, the hole is there the right shape - see attached image. The black spots are reflection from the flash. When I looked at at the photo I wondered what it was- just been back out & checked. All the metal is sound.
So, to grind it off, how would you go about it. I’ve only got a large grinder & it certainly wouldn’t be able get it in there. But I like your idea of grinding it off

Nigel Axtell

I would grind it off, but the question is why was it welded in the first place? What were they trying to fix?

The "good" hole that you illustrate looks as if it is badly worn oval, and the inside view if the washer doesnt look concentric with the original large hole. and where are the holes for the tangs? All suggests to me bodged attempts to rectify wear which probably occurred because of use of wrong parts or wrong assembly.

Final point, although the metal might look sound it is thin and they aren't the most robust of suspension mounts! I would be inclined to replace both mounts on that side, even if you need to get someone else to weld them for you.
GuyW

To grind the welds off I'd use a Dremel; a bit slow and painstaking but as you say an angle grinder won't get in there. However I think I agree with Guy that going back to the chassis leg and welding in new flanges would be the best solution. Then you can guarantee the fit, the strength and the geometry. If you want some correct bolts with tangs and the stepped washers etc I've loads of very good used ones, happy to send you a set for postage.
David Smith

looks yo me like PO didnt have the correct tanged washer and just botched it .
mark heyworth

Without the tangs properly located, the lower wishbone bushes will grip the pivot pins and rotate them back and forth in the large holes in the chassis brackets as the suspension moves. Add road grit, salt and water to make a grinding paste and the locatiing holes will wear very quickly. Even the good holes in the photos appear to have worn oversized and oval.

It just shows that the assembly detail of making sure that the tang on the washer does locate correctly into the little slot is really important.
GuyW

This thread was discussed between 03/01/2021 and 10/01/2021

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