9 replies to this topic

[gazza01]

Hi all. 

I have a small amount of play on one radius arm. Whe greased it hardly moves.

However i have read some threads where a lot of the more experienced guys say changing the pin may sort it.

Can someone please give me a run through procedure for changing this the easiest way please. 

[David128]

Hi   IMHO it much easier to get an exchange unit. Changing the pin may not solve on its own as some times the bush wears and then needs to be replaced also. Then needs reaming to size.

[Carlos W]

Hi   IMHO it much easier to get an exchange unit. Changing the pin may not solve on its own as some times the bush wears and then needs to be replaced also. Then needs reaming to size.

 

Completely agree

[nicklouse]

The bush is softer than the pin.

Guess what wears first?

[xrocketengineer]

Having rebuilt the the radius arms and replaced them myself, I would say, that if you are in the UK, the exchange unit is the way to go. Here is what I did to rebuild them since it was cheaper on this side of the pond than the exchange unit:

 

http://www.theminifo...th-radius-arms/

 

Just replacing the pin could turn into a nightmare and might not fix the problem. There is a lot of work involved taking the radius arm out, particularly on the left side since the fuel tank has to come out to undo the top shock mount and if it is an injected car, the fuel filter might be in the way also. Don't forget brake lines and hand brake cable that need to be disconnected. Also, I lucked out and only one attachment bolt broke off for a radius arm which I fixed with a thread repair kit. So, I would do the work only one time with a good replacement part. 

[tiger99]

Actually, because the bush is softer, the pin often wears more. One of these surprising things. But when worn, they both need changing and an exchange recon arm is the practical way for most people, as has been said.

[nicklouse]

Actually, because the bush is softer, the pin often wears more. One of these surprising things. But when worn, they both need changing and an exchange recon arm is the practical way for most people, as has been said.

I was kinda wanting this response but I was hoping for the reason which I have forgotten. But I am guessing it is the wiping action is spread over a great area on the bush so it wears less? Cause when you look at a well worn pin it is a nice arc section.

[xrocketengineer]

Apparently there is also corrosion of the pin in the bushing area due to dissimilar metals. One of the bushings is still stuck on the pin. The other came off but the bushing area is badly corroded.

 

[Ivor Badger]

The bush is softer than the pin.

Guess what wears first?

The pin and that is not a guess.

[tiger99]

Correct, and indeed no guess to many who have had to overhaul their radius arms. Likewise a crankpin can sometimes wear faster than the relatively soft bearing shells. Not the nitride hardened crank of a Cooper S perhaps. One of the reasons is because hard particles will embed themselves in the softer surface and scratch the harder one as they slide across it. And, if the Mini is not greased regularly, ideally every 2000 miles, there is indeed dissimilar metal corrosion of the pin, because water gets in.

 

If the radius arm bushes are correctly reamed and the front balljoints correctly shimmed, regular greasing gets very high mileage out of them. Much of the trouble we see on this forum is as a result of various previous owners having never attended to the greasing, because it is something that you don't do on modern cars. Yet it takes only a few minutes to do all 8 nipples.