11 replies to this topic

[BJst416]

Hello everyone, I've got a question for the mini experts.

With regards to the Radius Arm repair Kit:



"The bushing must be reamed/honed parallel with the centerline of the pivot hole, so it requires assistance of a machine shop"

Could someone explain what that means? I can't find reference to that install in any of the manuals.

Is this in reference to the brass insert? does it need to be resized to the shaft diameter? (bottom left in the picture?)

The ever so helpful Haynes estates:

"The removal and refitting of both the bearings and the line reaming of the bronze bearing to suit the outside diameter of the pivot shaft, entails the use of several special tools. As there is no other way of satisfactorily carrying out this work, it is strongly recommended that the arm is take to a Rover dealer for the complete bearing removal, refitting and reaming to be carried out" Ch 10, Art 19

I don't know if today is my slow day and i'm not understanding the language so well or I just don't know squat about these procedures.
Please understand that there is no such a thing as "mini especialist garage" in this lame country.

Thanks in advance

[Bungle]

i think most places sell exchange arms

saves all the problems of finding someone that can do the work

[RobG295]

Basically you have to remove the old brass insert, and put the new one in its place. Then using a reamer of the correct size ( don't know what size this is as i used an adjustable one) ream out the brass bushing so that the shaft fits snugly.

[Dan]

You need a special tool to line-ream the bronze bush to the finished size of the shaft after fitting. Reaming is a machining process for creating an exactly round hole (which drilling or honing will never do in some materials) of an exactly accurate size. It is supplied rough finished but cannot be finish machined to size before fitting because it gets compressed into place slightly and this changes the internal diameter. There are a few methods of bodging it in but they are best avoided. You need to find a machine shop that has reaming equipment capable of finishing the exact size, exactly in line with the roller bearing at the other end. That means the need a reamer with a long shaft of exactly the size of the radius arm shaft that will extend through the bearing to keep it aligned wile cutting the bush. Good machine shops should have such tools even if they don't have the official Rover special tool.

[dklawson]

Over here Minis are few and far between so parts like professionally reconditioned radius arms are quite expensive.

I made (modified) my own reamer for this task and you could do the same if you have access to a lathe , some round stock, and a welder. You can see a picture of my reamer at:
http://home.mindspri...ArmReamer01.jpg

Buy a 13/16" reamer (0.8125"). Cut a piece of 7/8" diameter steel rod and drill it out so it fits on the shank of the reamer. Tack weld the steel rod the the reamer shaft (3 spots on each end). Then mount the reamer on centers in a lathe and turn the 7/8" rod down to 13/16" and turn down the reamer shaft (if necessary) to fit your hand drill.

After you've installed all the rebuild parts in the arm you insert the reamer through the needle bearing. The rod you welded to the reamer shaft will support the reamer in the needle bearing guiding it straight through the bushing as it is cut to size. Always use reamers on LOW speed and use lots of oil for coolant. Once the reamer passes through the bushing, do not pull it back... release it from the drill chuck and pull it out the bushing end so all the chips go out with it.

[fastroadie]

You can use a drum brake cylinder honing tool, it is narrow enough to fit in, get it on the drill and try for fit every so often, use a bit of soft wood and gently tap it in. PS take your time.

[fastroadie]

forgot to say, do internet search for radius arm recon, there is a pictorial step by step guide out there somewhere, I printed it out, came in very handy.

[dklawson]

Honing the bushings is often presented as a DIY method for sizing them. However, there are two issues at hand. If the bushing is NOT exactly concentric with the needle bearing... the bushing has to be opened up excessively to allow the shaft to pass without binding. The other issue is that brake hones can be difficult to use to remove the amount of material involved. You may find that you end up with a tapered or oversized bushing bore. In effect, you install a new bushing and promptly enlarge it to the point its "more worn" than the part you removed.

If you choose to hone the bushing work carefully and check the fit of the shaft frequently during the process to remove the minimum amount of material.

[BJst416]

Ohh, this is way more understandable than before.

13/16" is that the shaft O/D or the neddle bearing I/D?

I have explained the process to the machine shop and they say they could do it.
So might as well do both sides since the machine shop will charge just a bit more for 2.
Meanwhile i´ll entertain myself painting and fitting new brake hoses on the subframe.

I´ll do a seach on the procedure as fastroady mentioned, maybe we can put something together for the FAQs, ideas...

Thanks again everyone.

[dklawson]

I don't have a radius arm shaft to measure and my reamer is presently packed away in the attic. (It's not a tool you use every day!). From memory, the shaft is 13/16". To confirm this for yourself, measure the shaft supplied with the rebuild kit.

If the shop is willing to do this for you, take them the shafts from the rebuild kit. They will ream or bore the bushings to fit the shaft and there will be no question about the size.

[fastroadie]

Found the site. www.eunos.com/keith/mini/files/radius_arm_short.pdf. pictorial step by step.

[BJst416]

Found the site. www.eunos.com/keith/mini/files/radius_arm_short.pdf. pictorial step by step.

Yes that´s the one. I found it too, very helpful guide. Thanks for posting it.

DK: yes, I´ll take the shafts to the machine shop that way there will be no room for errors.

As always, TMF is just outstanding. Thanks.