repsolypf Posted February 17, 2007 Report Share Posted February 17, 2007 I have replaced the top bearing in the frame - no problem. However the bottom inner race that's fitted to the actual headstock is proving to be a real pain to remove. I dont want to be too brutal with it as I am worried about damaging the shaft that the new bearing will have to be seated on. I have already managed to destroy the cage and bearing races and am now left with the seemingly impossible job of getting the remains of the bearing housing off the shaft. Many thanks for any tips or advice on how to proceed Quote Link to comment Share on other sites More sharing options...
bilco Posted February 17, 2007 Report Share Posted February 17, 2007 get some heat on it and then they should lever off nice. Quote Link to comment Share on other sites More sharing options...
copemech Posted February 18, 2007 Report Share Posted February 18, 2007 These can be a real bitch! You must "split" the remaining race by cutting 2/3 the way through it with a grinding disc ,such as a Dremel tool, to score it. Do it at an angle as not to dig into the bottom yoke.Then take a cold chisl to "split" the race. You actually have to fracture it. Then it will drive off easily. Putting heat does no good as the ali shaft expands at a greater rate than the bearing! To go back with the new one, you may want to actually freeze the shaft in the frig, and heat the bearing. You can go as high as 300c on the bearing, and it should drop on, be sure to bottom it by hand or it will bounce up and then stick! You have approx 10 seconds to perform this operation! Rediculous, I know~ If it is a tight one, the only other install option is to polish down the shaft and even then, you need a good installer tube to drive the new bearing on! Hope that helps! Quote Link to comment Share on other sites More sharing options...
barrybaines Posted February 18, 2007 Report Share Posted February 18, 2007 These can be a real bitch! You must "split" the remaining race by cutting 2/3 the way through it with a grinding disc ,such as a Dremel tool, to score it. Do it at an angle as not to dig into the bottom yoke.Then take a cold chisl to "split" the race. You actually have to fracture it. Then it will drive off easily. Putting heat does no good as the ali shaft expands at a greater rate than the bearing! To go back with the new one, you may want to actually freeze the shaft in the frig, and heat the bearing. You can go as high as 300c on the bearing, and it should drop on, be sure to bottom it by hand or it will bounce up and then stick! You have approx 10 seconds to perform this operation! Rediculous, I know~ If it is a tight one, the only other install option is to polish down the shaft and even then, you need a good installer tube to drive the new bearing on! Hope that helps! In this case surely freezing the shaft would be a good suggestion for removal too? Quote Link to comment Share on other sites More sharing options...
mad4it Posted February 18, 2007 Report Share Posted February 18, 2007 As copemech say's the only way to get the bearing off properly is to grind it as far through as possible without damaging the shaft then get a chisel and give it a good hit in the slot you have just ground out it will then crack and just pull off. As for re fitting it just drop it on the steerer tube and knock it on using a punch it will not be to tight to get on. Quote Link to comment Share on other sites More sharing options...
boofont Posted February 19, 2007 Report Share Posted February 19, 2007 I would speak to John Lampkin but if is the same as a Scorpa it should just push out. On my SY the bearing was really tight but after speaking to Birks he assured me that it would push out. I used a bearing press and pushed it the rod through a socket, the bearing was supported by the socket. Quote Link to comment Share on other sites More sharing options...
repsolypf Posted February 23, 2007 Author Report Share Posted February 23, 2007 These can be a real bitch! You must "split" the remaining race by cutting 2/3 the way through it with a grinding disc ,such as a Dremel tool, to score it. Do it at an angle as not to dig into the bottom yoke.Then take a cold chisl to "split" the race. You actually have to fracture it. Then it will drive off easily. Putting heat does no good as the ali shaft expands at a greater rate than the bearing! To go back with the new one, you may want to actually freeze the shaft in the frig, and heat the bearing. You can go as high as 300c on the bearing, and it should drop on, be sure to bottom it by hand or it will bounce up and then stick! You have approx 10 seconds to perform this operation! Rediculous, I know~ If it is a tight one, the only other install option is to polish down the shaft and even then, you need a good installer tube to drive the new bearing on! Hope that helps! Many Thanks copemech - everything went exactly as you have set out here. The dremel cutter worked a treat. I put the headstock shaft in the freezer for about 30 mins and stuck the bearing in the oven (200 deg C Gas mark 6) for 10 mins and the bearing went on with no problems at all. Great stuff - now fixed and bike reassembled. Quote Link to comment Share on other sites More sharing options...
copemech Posted February 24, 2007 Report Share Posted February 24, 2007 Good job mate! Cannot figure why those things are so tight to begin with! But a bit of patience is better than beating the crap out of it! I learned it the hard way! Good to share, just a Paioli thing I think! Reminds you to keep the headstock in grease! Quote Link to comment Share on other sites More sharing options...
neillydoc Posted February 24, 2007 Report Share Posted February 24, 2007 Had problems with the removal of the bottom bearing on my Beta Techno, but now, thanks to ur advice, new headind bearings fitted, and lots of grease used. Thanks guys. Cheers Neillydoc Quote Link to comment Share on other sites More sharing options...
eddie_lejeune Posted February 25, 2007 Report Share Posted February 25, 2007 i spray the bearings around the headstock with wd40 every time after washing it. these are a ******* and although i havent had one off i guess they are put in dry at the factory. Quote Link to comment Share on other sites More sharing options...
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