Radius arm end float

[Daz1968]

Has anyone experienced end float on radius arms after fitting new bush, bearing and shaft, I have had to machine approx .020” from the end shoulder of the shaft to get them to fit correctly. Was easy enough to do on a lathe held between centres, just used my dremmel with a small wheel to cut it back. I can only presume that the width of wet radius arm is either smaller than a dry one or mine have worn on the ends due to lack of greasing in the past. I didn’t have any issues on my mk1 that was dry.

[1071bob]

Had the same problem on mine, the bushes and bearings were so bad on mine that the thrust faces on the end of the radius arms had worn away. I had to reface the ends of the arm which made the new shaft too long, I found it easier to put a 13/16" counterbore into the thrust washer to achieve the correct endfloat.

[Daz1968]

Thanks at least it has an explanation, my shafts and bushes were badly worn, almost worn through the bush and shaft had large step, so not surprised they are worn elsewhere. I chose to machine shaft as it was easier to hold in the lathe but counterboring the washer is probably better if it machines easier, the shaft is pretty hard and I had to revert to using the dremmel to get an effective cut. I don’t have any tipped tools.

[Peter Laidler]

But don't forget that now you've taken .020" off the length of the shaft, the outer brackets will now have to be moved INWARDS a further .020" to compensate. Nothing to concern you unduly as the holes in the outer brackes will (?) be able to cater for it. But just be aware.

To solve this undue wear in the future make sure that you modify the shaft so that in future, the grease you pack in from BOTH ends gets DIRECTLY into the bearing/bush AND across the thrust washer faces. End of any future problem

[Daz1968]

holes still aligned ok, but I doubt the geometry has been disturbed too much it’s effectively 0.010” off centre to original position. I will check geometry after car set up anyway. I haven’t modified shafts as per your guide but i have retained the steel inner tubes they will be filled with grease until it comes out both ends. Think issue was they had never been done before so had been in use since 1968 in all sorts of weather and probably not greased to correct service intervals,

[dodge44]

Surprised no-one has mentioned the obvious. Many moons ago I asked our sheet metal shop to bash out a few 20swg stainless shim washers to take up the slack in my radius arms. Only needed a pair but they went between the arm and outer washer with the usual rubber seal over the top. It was supposed to be a short term expedient pending replacement of the arms but such is the way these things go it must have lasted well over 10 years in the end and even then it was wear in the bearings / shaft that led to their retirement!

[scooperman]

revisiting this old thread. I have not found any specification for how much end float the arm should have. It seems like the clearance does increase with time and wear, so initially should it be close to zero, maybe just a few thou?

[Peter Laidler]

I'm not sure that the end-float of the swinging arm on the fixed axis shaft does increase with wear....., certainly anything in excess of, say, .010 or so. That's because while the swinging arm does rotate, it can rotates by some 20 degrees* or so, up and down. And even then, the swinging arm isn't loaded left or right - unless you are cornering hard. Each end also has a thrust washer that is greased to allow for ease of rotation.

I say that each end is greased. This is not actually correct unless you have modified axis shafts. That's because....... Anyway.....

* just a guess so feel free to correct me

Good to see Daz mentioned within the thread. Are you still with us Daz......?

[Spider]

revisiting this old thread. I have not found any specification for how much end float the arm should have. It seems like the clearance does increase with time and wear, so initially should it be close to zero, maybe just a few thou?

Factory clearance was a nominal 0.005" total (0.0025" ea side - in theory !). If greased regularly and best done 'unloaded' (while jacked up), the grease will get between the thrust washer and the thrust face on the arm - but only if there is decent grease tubes in the arms.

[Peter Laidler]

Thanks for correcting my end-float guess Spider. If you modify the the axis shaft, you can leave the grease tubes in place but they are redundant as each bearing/bush is greased independently

[scooperman]

thanks for the clearance info. Replaced the front hydro hoses on the 68 Elf in 2011 https://elf-hornet.forumotion.com/t1303 ... o-dry-cone , the right rear hose recently gave up so had that corner all in pieces. As I was finishing reassembly I noted a lot of side play, measured >.015" , thus my question. I will think on what to do for a long-term fix, but since dodge44 above had good luck with shims, I will add a shim for now to get down to less than .005".

[Peter Laidler]

Not really part of the answer but Dodge is right. There's nothing wrong with using shims to achieve exact/close tolerances in engineering. But we were taught during our old apprenticeships that IF there was a tendency for a shim to rotate (unlikely in this case) then it's good practice to use a thrust washer machined to thickness. There was another rule of thumb but I forget what it was!!!!!