Replacing the swinging arm bushes on a ’59 Triumph Thunderbird

Discussion in 'Northern Thailand - General Discussion Forum' started by ianyonok, Mar 31, 2012.

  1. ianyonok

    ianyonok Ol'Timer

    Dec 9, 2008
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    It was high time to do something about the swinging arm bushes on my old Thunderbird. They had never been done properly when I restored the bike years ago, due to lack of the correct tool. To do the job properly, it is necessary to line ream the two bushes as they reduce in diameter after insertion.
    After sniffing around on the web I found the perfect tool for the job. Taylor and Jones in England make a spiral fluted reamer which attaches to a pilot rod holding a sliding conical bush. The spiral flutes glide over the splits in the bushes without jamming and the cone bush and pilot rod keeps the tool in line. This company would not sell to me directly, but I found Shaun Burke at Cromwell Tools in Bangkok, who could get the tool for me. Shaun was extremely helpful in supplying what was needed. The original quote was about 7000 Baht and 10 weeks wait while they make the tool. I was in no great rush so I asked Shaun to get me the tool. Not cheap, but top quality and exactly what was needed. Shaun then managed to pull strings with Taylor and Jones and they delayed their other jobs to make my reamer! Someone from the company was coming over to Bangkok and hand carried the reamer over to Thailand. Someone else who worked with Shaun was then coming up to Chiang Rai, so they carried it up here. I took a run down to Bahn Du and met up with this guy’s sister who gave me the tool. So, actually, I got the tool within 10 days! Thanks Shaun, you’re a star.

    This is a big job on a pre-unit machine involving a major strip down. So far, footrest, exhaust, rear shocks and seat off.

    I don’t use a gasket here as the mating surface profile is small. Gasket sealant works well and the outer primary case comes off with judicious taps with a hide mallet.

    All looks good inside.

    I fitted a cartridge oil filter below the swinging arm on this bike for engine longevity.

    Pretty gungy looking…

    Alternator stator and rotor off, pressure plate and clutch plates out. Clutch locking tool in. Chainguard, mudguard, rear wheel, rear wheel brake hub and torque arm off.

    This special puller takes the clutch centre off the gearbox shaft taper.

    Engine sprocket, clutch centre, chainwheel, primary chain and shaft keys off.

    Inner chaincase off. The primary chain on the pre-unit bikes has a split link which makes life easier. Now I can see the end of the swinging arm pin.

    After removing the two end discs and holding rod, then slacking the gearbox adjusters off and rocking the gearbox forward, I was able to easily tap the pin out the with a brass drift on right side of the bike.
    Definitely a bit gungy…. This bike gets used a lot….

    You can see the swinging arm pin holding lug which is brazed into the frame upright tube. Bike frames of this era were made with cast iron lugs brazed onto the frame tubes.

    All these parts needed removing to get the swing arm out.

    Swing arm and pin for cleaning and inspection.

    Just a few of the tools used…… The hydraulic work bench is home made but is very useful.

    I had made this bush removal tool some years ago, with an old pre-unit gearbox adjuster rod.

    The pusher on the left squeezes the bush into the hollow tube on the right. The double ended Whitworth ring spanner was inherited from my Dad. It’s a “King Dick”, probably at least 60 years old.

    The original right side bush just about out.

    The replacement split phosphour bronze bushes, acquired on ebay from England needed enlarging a little to be a tight fit in the sockets.

    Red loctite ensures the bushes will be secure in the swing arm.

    Bushes in, ready for reaming.

    The new pin, complete with central hole for grease to enter the centre of the hollow pin and end holes for the grease to come out to meet the bushes.

    Internal bush diameter.

    And external pin diameter, so about 12 thou to ream out.

    Here is the beautiful tool from Taylor and Jones. The spiral fluted adjustable reamer attached to the pilot rod and sliding cone. Real quality item.

    I didn’t have a tap wrench large enough, so used a socket and T bar to rotate the tool.

    The inside finish after line reaming. The spiral flutes gave a nice smooth action as the tool passed through the bushes. The small scratches help hold grease inside the bush.

    The reamer going through the bush. A quarter turn of adjustment on the reamer took out about 2 thou per pass.

    All cleaned up, ready to re-fit the arm.

    The socket cleaned and ready for the pin.

    It transpired that the new pin was loose in the frame socket, so I decided to re-use the original pin, which was 8 thou larger in diameter and a good interference fit in the frame. Thus, I had to ream some more material from the bushes.
    My frame was modified by having two bolts fitted that pass through the frame and screw into the pin to ensure it cannot rotate. The central hole is inline with the external grease nipple and the two securing bolt holes are either side.

    Copper headed hammer to drive the pin into position.

    A nice snug fit.

    Here you can see the securing bolts either side of the grease nipple.

    Internal rod and end discs in position.

    When grease is pumped into the nipple, it fills the external cavity between pin and frame lug, then travels into the centre of the hollow pin out to either end and back out through the 4 holes each end, to meet the bushes.

    Engine and gearbox cleaned up, ready to re-fit the inner primary case.

    Inner primary case, engine sprocket, primary chain, chainwheel, and clutch centre fitted.

    Alternator rotor, stator and adaptor re-fitted.

    Clutch plates and pressure plate, final drive chain, brake hub and torque arm all back on.

    The 54 year old bike rebuild complete and ready for the Chiang Rai April Fool’s Day Run.... I wonder if there will be anyone there at the meeting point...?


    So, if anyone needs any quality tools contact;

    Shaun Burke
    Cromwell Tools, Bangkok.
    [email protected]

    Cromwell-Tools (Thailand) Co., Ltd.
    2070 Moo 1, Old Railway Road,
    T. Samrong Nua, A. Mueng Samutprakarn,
    Samutprakarn Province 10270

    Opening Times
    Monday - Thursday 8.30 am - 5.30 pm
    Friday 8.30 am - 4.30 pm
    Saturday /Sunday Closed
    Tel +66 (0) 2 743 5353
    Fax +66 (0) 2 743 5350:
    Mobile +66 (0) 81 803 2653

    Best wishes
  2. ronwebb

    ronwebb Ol'Timer

    Jul 25, 2010
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    Looks like a surgical procedure Ian and a bit techie for me but I am pleased that you managed to put that very fine reamer to good use.

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