Removing brass/bronze swing arm bushings?

Paul LeClair

Paul LeClair

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Calgary, Alberta, Canada
more on the swing arm bearing/bushing topic. I want to fit the 4 inch gold Astralite wheel to my 79 1200 180, and it is too wide to fit in the stock 180 swing arm.

as usual, Wolfgang had what was needed, and I just took delivery from him of a well used but wider swingarm. modified to fit a 180 pivot point, but the bike it was originally made up for used a larger swing arm pivot.

I am not interested in modifying my frame to accept a larger swing arm pivot diameter, and am going to use this wider swing arm with brass/bronze bushings rather than needle bearings.

so, attached re two photos of what I am working with. I have the new bushings ready and to size, both od and id for what I need to fit my 79 1200.

the old bushings presently installed are exactly the same size as the inner tube in the swing arm, meaning there is absolutely no way to get behind them to drive them out. I have a Pro Motion bearing removal set which has an insert perfectly sized for the bushings, I drove the wedge into it with a small sledgehammer, then proceeded to try to drive the bushing out. When it wouldn't move, I heated it with a high temp heat gun until the paint blistered and stuff came bubbling out from between the bushing and the swing arm, and tried again, but it just isn't budging, not even a fraction.

with needle bearings I would just mig weld something to the bearing and use that for purchase to drive it out. I might even grind flats onto a washer and slide it in behind, but with these bushings the id of the bushing is exactly the id of the swing arm, and there is nothing to get a purchase on. I am presently out of oxygen in the tanks of my oxy/acetylene rig.

I was just eyeing my Dremel with the thought of maybe cutting a couple of slots in the bushings..... but I thought I would ask here first. I don't mind buying a new tool if necessary, I just don't know what to try next.

Paul LeClair
 

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Poor designing on the part of whoever built the swing arm, Paul.

Guess your only option will be the good ol' Dremel...

When installing your new bushings, provide for a means to get at the rear to use a puller of some kind, then no smart arse can make a similar comment in 20 years time. :D

piet
 
Paul, would it be possible to drive one of the bushings further into the pivot tube thus pushing the opposite bushing out and upon removing the inner spacer allow you to then drive the remaining bush out from behind? Never done it, just a thought FWIW.

Stu
 
Dremel away Paul. I've got a triple swingarm that I threw under the workbench in disgust. I spent a couple of hours making up an expandable puller/whacker for this job.

On first attempt, there were needles falling out everywhere  :D  and the expandable whacker hit the workshop floor. No cage though  >:(.......... tunover swing arm .......... all I managaed to do was knock off the radius' off the cage >:( >:(.

Tried the dremel and gave up and threw the swinger under the bench >:( >:(. Looks like I'll be out with the welder next ::).

Good luck.
 
I?ve not tried it on bronze but when we had trouble removing iron liners from marine diesel engines we would run a line or two of weld down the liner. When the weld cools it shrinks pulling the liner in and making it easier to remove.

If you haven?t got the gear for brazing then go to a workshop that has and ask.

I?m not sure of how much brazing shrinks as it cools but it is worth an ask.

Rod
 
Using just the blade hacksaw a slot into the bushing as deep and down as possible then use a sharp chisel to roll the old bushing edge down, it will eventually tear and separate reducing tension on the swingarm and allow for removal.
 
It's not easy to cut an internal bush lengthways with a Dremel. The bush is quite long in relation to the diameter, and there's not a lot of room to work in there.

If you have a half-decent drill press, you would be better off clamping the swingarm to the drill press table with the bush axis vertical and running an end-mill cutter down the side of the brass bush. Much better control than with a Dremel and less risk of chewing chunks out of the swingarm bore.

It may also be worth experimenting some more with heat/cold:
Put it in the freezer for a few hours. The brass will contract more than the steel and loosen it a wee bit and might make it easier to knock out.  The colder you can get it the better.
Better still if you can freeze the bush while the swingarm is hot. Try heating the whole thing then hit the inside of the bush with freeze spray. With a bit of luck it'll fall out.

Cam
 
thanks for the suggestions, guys.

I walked away for a while before I could do anything stupid..........

having not had any luck with heat, I am going to throw the swing arm in the deep freeze overnight and have another go tomorrow.

Paul LeClair
 
IAG said:
Using just the blade hacksaw a slot into the bushing as deep and down as possible then use a sharp chisel to roll the old bushing edge down, it will eventually tear and separate reducing tension on the swingarm and allow for removal.
Click to expand...
It is a bit hard to see in your photo but it doesn?t look like there is a step in the swingarm. In the old days we just assembled a hacksaw through the swingarm and did as IAG says. The bronze is easy to cut with hacksaw. Elbow grease and an eye on when to stop before you hit steel.
 
hi Paul, I know what its like to be out of oxy/acet, since I have signed my gas account (BOC) over to my son who uses it in his fabrication business, the trouble is he uses lots of mig and argon and hardly any oxy/acet, so now that we are out of acet, I cant use it, and he wont buy any more, so much for giving him free electricity for the workshop, free gas (4 types) for years and no rent for his scaffold lorry and storage rack,all of that must be worth 400 quid a month, all I want is a bit of gas!

What I would do is tap a thread in it, any thread at all, whatever fits the bush, even a pipe thread, then make a simple spacer, and useing a bolt (or a pipe end) screw it in and pull it out, if it feels like it is not going to play, then a thump with hammer, from the other side (remember it is now plugged) might help or a push in a press, Dont use any heat, as the non ferrous will expand more than the steel and make it an even tighter fit, dropping it in a bucket of liquid nitrogen would be realy good (-197 degrees C) much better than a domestic freezer (-18 degreesC)
CLEM
 
Get yourself a big old tap, I use a 1 1/8 Whitworth I think but anything of a suitable size will do, run it into the bush then press the whole lot out from the opposite side. Dremmel indeed.....great for doing your nails apparently  ;)


  Keith
 
Hey Paul

''Whilst you are at it'': How about bracing the arm with an under and over  brace, may as well slip in a space frome too........ :LOL:

Plenty of ideas here and good luck with your bush.

                              Cheers
                                      Matt
 
thanks, all!

there is a "step" inside the swing arm, so the bush is a flush fit inside, no way to get purchase or to cut the bush without also cutting steel.

swing arm has been in the freezer overnight, I will have another go at bashing the bush out with the expanding bearing removal tool, if that doesn't work I think I'll go shopping for a suitably sized thread tap, as I don't presently own anything anywhere near that big.

oh, and Clem, I own my large oxy and acetylene tanks outright, but they are over ten years old now and have to be "recertified" every ten years as safe for pressure before anyone will fill them, the recertification process is not cheap, and I just haven't gotten to it, yet.

Paul LeClair
 
I see what you mean Paul.

The bloke that made the ID of arm and bush the same size wants shooting.
However, the new bushes will obviously be much easier to belt out with a drift when the time comes.

When you press the new bushes in - assuming they are a transition or interference fit, don't forget the bush will shrink just a little bit and may be tight on the swinging arm spindle, or just reduce the clearance a bit.
 
The new bushes will need to be reamed after fitting. You need to ream through the bore using the opposite bush as a guide for the reamer.
Last time I did a set of bronze bushed (Ducati) I took the swinger and pivot shaft to an engineering shop to get it reamed to fit. The bloke who did it reamed one bush, turned the swingarm over and reamed the other bush, independently of each other. The bloody things didn't line up! The shaft was a nice fit in each bush but wouldn't go right through both.

 
laverdakeith said:
Get yourself a big old tap, I use a 1 1/8 Whitworth I think but anything of a suitable size will do, run it into the bush then press the whole lot out from the opposite side. Dremmel indeed.....great for doing your nails apparently  ;)


  Keith
Click to expand...

That's lateral thinking ......... good idea.

Paul, when you've done yours, can you pop over here and do mine for me. :LOL:
 
overnight in the freezer didn't do me a bit of good, bushings still wouldn't move with the bearing remover tool.

off I went to Princess Auto for an inexpensive set of pipe taps, the 3/4 tap was a perfect fit in what I was working with.

threaded the bush, left the tap threaded in, bashed the nose of the tap with a rod and a small sledgehammer from the other side of the swing arm, thought I was going to break the tap or strip out the threads, but eventually the bushing started to reluctantly budge a little bit with each bash, got one side out, then repeated on the other. Turns out the tap survived OK, but I should have bought a pipe end plug or something to thread in and bash on, will know for next time.

attached two photos. Thanks to those who suggested the tap/thread approach, worked really well, no damage to the swing arm. now that the old bushes are out I am able to measure properly, the new bushes are too long, need to cut them down to proper length, and I am going to figure out how to cut a couple of removal reliefs in the step(s) inside the swing arm to be able in the future to get the new bushes out without all this drama...

Paul LeClair

ps now need to somehow fix the pick up feed on my sand blasting cabinet, with my new compressor I have lots of air volume but the glass bead isn't being picked up properly, guess it is what I get for buying a really inexpensive but large blast cabinet....
 

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