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MG Midget and Sprite Technical - Frogeye rear radius arm fitment

Rear suspension and axle all fitted on my slowly being reassembled Sprite a few weeks ago. But on going over it all to check bolt tighteness I realise that the end of the trailing arms are free to "float" laterally on the special bolt that attaches them to the rear axle. One consequence is that tightening the bolt simply bows the sides of the welded-in axle bracket.

This doesn't seem right to me. Should there be some spacers alongside the metalastic bush at the rear end of the trailing arm so it is clamped as the bolt is tightened?

Checking the Moss catalogue drawing it shows a spacer bush (item 17) AHA5224 at the front end of the arm, where on mine there is no room for one. I wonder if this is an error on the drawing and this should in fact go at the rear end of the arm?
GuyW

Guy, On both of the frogeyes that I have owned there has been no spacer at the axle end of the radius arms, so I assume that this is correct. Seems a bit rubbish to me...
Simon
Simon Wood

Neither end should float. Use either spacers or washers.
Alan
Alan Anstead

Thanks Alan,
Front clamps up nicely without additional spacers or washers. Rear probably has 1/2" or more of "freedom". Didn't seem right to me! Lathe to the rescue then.
GuyW

IIRC mine had spacers so the metalastic bush at the axle end was clamped securely. The front end also has spacers but they're usually welded to the bracket that bolts to the body.
David Billington

Frogeyespares list them http://www.frogeyespares.co.uk/item.asp?cID=15&scID=35&iID=128&page=Austin_Healey_Sprite_Rear+radius+arm+spacer

Looks like that link will have to be copied and pasted.
David Billington

That's interesting. My original BMC Mechanical Service Parts List AKD3566 Pages MH2 and ML2 don't show any spacers. Were they fitted as original equipment?
Simon Wood

The bush listed on Moss should be used at both ends of the radius arm, there should be 4 per car, both arms, both ends. Check item 9 on this sight, they list 4 needed per car: https://www.ahspares.co.uk/sprite/Suspension-Rear/default.aspx
Stan Kowznofski

GuyW, here's a photo of two of the spacers AHA_5224, I hope sufficient to show the dimensions. Early frogeyes with the early front bracket needed 4 of these little charmers, cars with the later top brackets (including all HAN6/7 and GAN1/2 cars) needed only two of them (one at the rear end of each link arm).


J.E. Davies

Thanks all. Mine is a later Sprite with the different front bracket, not requiring an extra spacer at that end. So I just need 2 for the axle ends. Looks like they are 7/16" X 5/8" x 7/16" bore.
GuyW

Stan,

9 is the radius arm bush, the metalastic one, item 11 is the spacer at the rear.

The front spacers can be seen in the attached image as part of the front body bracket


David Billington

My parts book AKD829 dated June 1960 indicates 4 bushes AHA 5224. Mine has one bush at the axle end. the chassis end does not need one.
Bob Beaumont

Whilst I am asking about this area of the car . . .
Mine has the later style radius arm mounting bracket that also carries the damper bolts. Where it bolts to the rear bulkhead there is a 1" wide horizontal stiffening swage about half way up the face of the bulkhead. The bracket bolts up against this.

Should there be some sort of packing pieces above and below the swage to stop the bracket from crushing it when the 3 mounting bolts are tightened up?
Or maybe my bulkhead panel is wrong? I made it from a flat steel sheet and spent a considerable amount of time adding that swage in 'cos that is how it is on my '71 car and also I could see it in several photos of that area on Frogeyes. But maybe it should have been left flat behind the brackets?
GuyW

Guy,

My car had 3 D shaped spacers there so the bracket was spaced off the panel and didn't crush the rib.

Frogeyespares sell them called "radius box spacer"
http://www.frogeyespares.co.uk/item.asp?cID=1&scID=1&iID=1188&page=Austin_Healey_Sprite_Radius+Box+Spacer
David Billington

When I rebuilt my frog I found evidence of packing pieces. I used washers to accommodate the swage.
Bob Beaumont

Guy, this photo of my shell might help. The bracket bolts to welded on spacers which are proud of what you refer to as the stiffening swage i.e. so the bracket will only contact the raised areas.
Bill Bretherton

Good. Thank goodness the time spent making the swage rib was worthwhile!

I didn't say this before as I wanted to hear the answers but when I bolted up the brackets I made a spacer to span the two top fixings from a piece 5mm flat bar and used some large wide washers as spacers for the bottom bolt.

It does however make an awful muck trap between the bracket and the bulkhead! I am inclined to seal around it with a mastic gun and frame sealant. Thoughts on that?
GuyW

Photo disappeared from my edit Guy so here goes again. Sealant sounds an excellent idea!


Bill Bretherton

Thanks Bill.
The other idea was to put a thin rubber gasket between the bracket and the spacers. Maybe something like inner tube.
Or an "engineering development" of that is a gasket cut from leather that extends down below the bracket and cut to fit as a dirt- excluding curtain around the spring and spring box opening.
GuyW

My parts manual is dated 1966. Odd that the spacers appear in an earlier edition but not in mine. Looks as though I will have to buy a couple. Anticipating outstanding handling improvement! :-)
Simon
Simon Wood

Simon, the spacers ARE listed in your BMC Service Parts list AKD_3566. They are item 19 on page ML2 (facing PLATE L1). Part AHA_5224. This list is not quite perfect because it doesn't say that only 2 are needed for the later style front bracket. In the 1st Edition Parts list for the Mk1 midget (AKD_1579) this same part is item 13 on page L1 - this correctly states '2 only required').


J.E. Davies

Here's plate L1 from AKD_1579


J.E. Davies

JED, yes I see that now, they are listed in ML2 but the illustration Plate L1 only shows item 19 at the bracket end of the link and not at the axle end.
Simon Wood

Simon, it's the same illustration that Moss use. I also thought the rear spacer wasn't shown. But the spacer is there at the rear end too, but it's not numbered and it looks as if it is a boss fixed in place to the axle bracket. Certainly an ambiguous drawing!
GuyW

Hi Guy,
As the above. Metalastic bushes include the spacer, but washers or DIY will do well. I use nylon bushes which are split into two 'top hat' sections and work well., but may be a bit harsh for road car.

I spaced the top bracket form the shell and sealed, Has worked well. Used same sealant to secure an 'inner tube' curtain hanging form the bottom of that bracket over the spring box, but before that I wrapped the spring with the same material to try to reduce the muck etc getting in.
Regards
Slowly

Hi, thanks. On mine the Metalastic bush at the front fits the bracket closely so no need for a spacer. At the rear it needs a spacer. Now all sorted.
GuyW

This thread was discussed between 14/09/2017 and 15/09/2017

MG Midget and Sprite Technical index

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