Thread: Ironhead Special tools
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Old 1st January 2009
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Default Transmission countershaft needle roller bearings drift

The two needle roller bearings on the counter shaft I replaced, heating the cases and trapdoor gently with a propane torch and gently tapping them out/in with a stepped drift I turned up on a mate's lathe.



They are two different size bearings so each end of the drift is differnt. The one for the trapdoor end includes a step on it the right thickness to locate the bearing the correct amount in from the surface, as specified in the manual.
Be sure to make the drift a few thou smaller than both the inner and outer diameters of the bearing so you can get it out after tapping the bearing in.

The propane torch needs to have the big burner head to get enough heat happening. Heat cases until you can spit on them and the spit boils and sizzles - 212 degrees F - and no hotter. It will not distort the cases if done gently and you keep the torch moving in circles all the time. Do not use oxy acetylene, it is too hot and can cause warpage.
I also found an electric heat gun will do the job, just takes longer.

Like all bearings, they can be changed cold but all you are doing is tearing the hell out of the aluminium and setting it up for the bearing to spin the housing due to the resulting loose fit, specially if the job has been done once or twice before.
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