Gday all, stripped down our rear suspension and checking over the trailing arms there is some piitting and wear on the pivot pins, i am thinking that we need new pins, needle roller bearings and bronze bush if so is this a costly job for a mechanic/machine shop to do or shall i tackle it myself??

Cheers TSB
Central Coast NSW

It isn't rocket science, once you get the old needle bearing and bronze bush out.
But you need either a piloted 13/16" adjustable reamer, or put the reamer in a lathe to hold it centred. Otherwise the bush won't be concentric with the needle bearing, and the shaft won't go through.

Most Mini repair shops (eg Mini Classic or Mini King) have the right gear to do it.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

Stu,

Caught caught up watching the MotoGP last Sunday so did not drop by. Can catch up this weekend. Have been through this process but had Greig at MiniClassic at Ermington do mine. As the good Doctor has indicated, it can be done with an adjustable reamer so long as it can be held square to the bearing on the other end.

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Dave K.
1979 Moke Californian + 1981 'Coke' Moke

Thanks Doc and Dave It all makes sense but how do you set up the reamer in a lathe so that it is concentric with the needle roller end. Bought the reamer and and found that Suttons no longer make the long series pilot Bought the short series but still havnt worked out how to ensure that any add on extension is in line with the reamer
Any clues would be much appreciated

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Mk1 Cooper S
Mini K Rally car

When I did mine, I tapped a true centred hole in the reamer body and made a pilot that screwed into it.
In the other end (where the needle bearing was) I made a neat fitting shouldered nylon bush that the pilot fitted into.

But someone recently did theirs in a lathe, they held the reamer in the lathe chuck and used the tailstock to centre the other end of the arm.
Looks an easier method to me (if you have a lathe).
There is a pic of that setup in here, somewhere...

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I did both my swing arm bushes a few weeks ago with a short ream and was very careful and took my time. The 1st bush was ever so slightly at an angle which I managed to straighten out to fit the shaft in and run straight with the bearing, the sedond one was almost spot on. Just need to try and keep the ream square and straight.

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

I see nothing at all wrong with this. They are not a high speed bearing - far from it, if it does bind a little, so what? It won't take long to sort itself.

Interesting the 13" wheel mokes run bearings both ends, but IMO Mini's and Moke's should run bushes both ends.

Thanks Doc. I had assumed that the reamer was hardened and would not be possible to drill. I will set it up in the lathe and centre drill then drill and tap
Advise appreciated

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Mk1 Cooper S
Mini K Rally car

In 1959, the UK Minis DID have bronze bushes both ends. But, the load on the inner one (where the suspension strut pushes) was too great, it resulted in the arms seizing on the shafts (maybe more greasing would have helped).
So, very soon they put a needle bearing in place of the inner bush, to take the load.
With the Oz bigwheel Moke, they replaced the outer bush with another needle bearing, again to take the extra load.

IMO, needle bearings are better, IF the shaft is at least 61C Rockwell hardness. If not, the rollers flake the soft shaft surface up.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

So what you are saying doc is that we could throw away the bronze bush in the kit and replace it with another roller bearing and thereby do away with the need to ream out the bush?

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1969 Cooper "S"
1967 Mini Deluxe
1973 Clubman Van (the fleet spare)
1978 ex 1275 LS ("Wizard" Eaton Supercharged)
2015 HSV GenF GTS(occasional drive & tow car)
2019 MINI F55 Cooper S

Only IF you can bore the outer end of the arm (bearing is bigger diameter).

Needs machining accuracy, and there may not be enough metal there for strength. I've not checked this aspect.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

The Morris 1100 has proper tapered roller bearings instead of the silly bodge up that the Mini has.

And I bet the Landcrab does too.
This is called PROGRESS....

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

You should see what they did to the Montego.

I've actually found that it's the depth of hardness rather than the actual hardness that is the produces this particular problem.

The problem with the needle rollers in the swing arms is the diameter of the needles themselves (hence why the 1100's and 1800's cope - bigger balls!). Needle Rollers are fine at higher speeds but a swing arm is sub-slow speed. Even with the high hardness of the needles and shafts, the needles shatter, I've seen lots and lots of them. No amount of grease helps either. I did fit bronze bushes into the Moke about 22 years ago. They are still there now and giving good service.

I am aware of the early failures that BMC had, but I suspect that it was the type of bushing that they use, some hard backed sintered crap.