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replacing stubborn castor housing bearings

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    replacing stubborn castor housing bearings

    I'm trying to replace the gritty bearings in my Kuschall K-4 but can't figure out how to get the old ones out.

    I've tried the screwdriver and hammer method with no success at all, it hasn't budged at all. I've also tired heating it with a hairdryer, but it didn't help and i don't feel confident with a blowtorch to heat it any more. All I've managed is to make it feel even more gritty and turns even less easily!

    I have new bearings ready to fit but I have to get the old ones out before the new ones can go in. Are there any tricks for stubborn castor housing bearings? If I can't do it then would it be more appropriate to take it to a bike shop or would a garage be better?

    Thanks

    #2
    Look to see if there is a snap ring in there somewhere.

    Comment


      #3
      Are you referring to the caster wheels, or caster fork bearings?
      Rollin' since '89. Complete C8

      Comment


        #4
        It's the fork/housing bearings. i.e the ones in the chair, where the castor stem mounts. Not the ones in the castor itself.

        I've looked for a snap ring but there is no sign of there being anything holding the bearing in.

        Thanks for any help anyone is able to give me.

        Comment


          #5
          I just replaced some on Quickie 2 Frog Legs. There were no snap rings on these like it shows there are. Got me worried because I saw the directions after I had them out. You need proper sized tools to do this. I used a 5/16 drift pin that has sharp edges instead of a screwdriver. I set the stem vertically on the corner of my table saw so that when I hit the drift pin with a hammer, I'd have a solid blow to the pin. Slowly working my way around the bearing it will work loose. Once it was down even with the table the stem could be held in my hand to finish the final drives. The second bearing could be done the same way or with a large socket (wrench). Installation has to be done with the correct size socket or other very similar tool. It has to be a socket that fits nicely inside the walls of the stem with no slop. But the socket also has to have walls thin enough to *only* touch the outside metal part of the new bearing. I think that part is called the race. These Frog Legs were especially difficult to pop the old bearings out of, so this time I slipped a little grease on the inner stems before assembly. One last note, be careful not to pound too long on any one side. That is keep checking the alignment, even with a perfect socket tool.
          I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

          Comment


            #6
            Doses this help? From the K-Series Service Manual:

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            Chas
            TiLite TR3
            Dual-Axle TR3 with RioMobility DragonFly
            I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

            "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
            <
            UNKNOWN AUTHOR>

            Comment


              #7
              As already noted, try driving them out with a drift rather than a screw driver. The handle of the screwdriver will absorb the shocking affect to drive them out. And angle the drift so your're contacting the other race, it sounds like you're driving the inner race, hence the bearings seem worse now. When installing them make sure you drive the outer race or you'll ruin the new bearings.

              Comment


                #8
                Thanks guys

                I've tried to get to the outer part of the bearing but can't get to it through the small hole in the other bearing. I've tried positioning the chair in all kinds of ways and using various tools to hit it through the hole in the other bearing but nothing is budging it. I've made sure that I'm not making it uneven and wedging it in place but it hasn't moved at all so I don't think that's the issue.

                The service manual is spectacularly unhelpful as it's the part which says 'check bearings and replace them if necessary' which is causing all this issue. It was a good idea to look it up though Chas and I appreciate that because I hadn't thought about it.

                I've made an appointment to see the bike shop on Saturday so hopefully they will be able to do something I can't. All I've achieved is to make the bearing worse and hurt my hypermobile hands through too much pounding with the hammer.

                I'm wishing I didn't start this job now though. I'm about to order a new TiLite and was just trying to get my Kuschall into a better condition ready to think about selling it. Oh well, now I've truly wrecked the bearing I'm going to have to replace it as I need the chair between now and whenever I retire/sell it. It was only supposed to be an easy job for the cost of a few new bearings!

                Thanks for all the help guys.

                Comment


                  #9
                  Is it conceivable you're driving them the wrong direction?
                  Chas
                  TiLite TR3
                  Dual-Axle TR3 with RioMobility DragonFly
                  I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

                  "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
                  <
                  UNKNOWN AUTHOR>

                  Comment


                    #10
                    Originally posted by chasmengr View Post
                    Is it conceivable you're driving them the wrong direction?
                    I doubt that. I bet it's a tight fit.
                    But I wonder if a bike shop is the correct place to go. Those bearings should be the same size as automobile alternator bearings. An auto repair person is more likely better equipped.
                    I have had periodic paralysis all my life. I lost my ability to walk in 2011 beginning with a spinal block, which was used for a hip fracture caused by periodic paralysis.

                    Comment


                      #11
                      Thanks nonoise, I'll try a garage after work tomorrow instead, and if they sort it then I'll cancel with the bike shop.

                      I'm definitely trying to move then in the correct direction but I bought the chair second hand and have had it for two and a half years, I don't know when or if the bearings have ever been changed so I guess they are simply stuck. That's good info about the garage having the tools though so hopefully they'll be able to sort me out tomorrow.

                      Comment


                        #12
                        Auto mechanic is indeed a great idea!
                        Chas
                        TiLite TR3
                        Dual-Axle TR3 with RioMobility DragonFly
                        I am a person with mild/moderate hexaparesis (impaired movement in 4 limbs, head, & torso) caused by RRMS w/TM C7&T7 incomplete.

                        "I know you think you understand what you thought I said, but what I don't think you realize is that what you heard is not what I meant."
                        <
                        UNKNOWN AUTHOR>

                        Comment


                          #13
                          Removing the caster housing bearings can be a bit of a challenge, but several things may help. First, clean the inside of the housing to remove any dirt, debris that may have accumulated. Second, find a sturdy flat surface to rest the housing on (something that you are not concerned with damaging). Third, and most important, heating the housing will almost certainly be required to expand the housing and release any bonding agents (like loctite) that the mfr. may have foolishly applied to the outer race of the bearing. A hair dryer will not be sufficient here. A heat gun for wiring/electrical work would be the bare minimum depending on the tolerances the housing/bearing were held to. Be aware of the type of finish on the frame as paint may be damaged from heating. Also, this will work much easier on an aluminum frame where the CTE difference between the housing and bearing is greater than between a titanium frame and bearing. Once the housing is sufficiently heated, use a metal rod, screwdriver, etc. passed through one bearing and resting on the inner race of the opposite bearing and a mallet or hammer to gently tap the bearing out of the housing. Work quickly and tap evenly around the inner race to free the bearing. With one bearing removed, the second bearing can be removed with a long 1/2 DIA bolt, some washers, a nut and a few wrenches. Again, heating the housing before pressing the bearing out. Installation is much easier and you can place the new bearings in the freezer for a while and heat the housing to maximize the CTE difference between the materials. The new bearings should be pressed evenly and fully seated into the housing using the bolt/nut/washers or an actual press. Do not install new bearings by pressing on the inner races! Damage to the bearing grooves or balls will almost certainly occur.

                          Comment


                            #14
                            One more thing, in order to press the new bearings into place using a bolt instead of properly sized dies that will apply the force to the outer races, the old bearings may be used. If the caster housing was machined properly, the diameter of the bearing seat will be sized to the bearing for only the 3/8" thickness of the bearing. The rest of the housing inside diameter will be machined slightly larger. Confirm that this is the case before using the old bearing to press in the new one otherwise you'll have 2 bearings press fit into the housing next to each other and removing them will be a nightmare. If you have any question on how to confirm this, ask first but it should be pretty apparent.

                            Comment


                              #15
                              Thanks Black Alloy, that's all really helpful.

                              I've also spoken to Kwik Fit and they've given me some ideas. I'll have another go at it and if I'm not successful then Shane at kwik fit says he can do it if I make an appointment. Fortunately it's not exactly an emergency, I rattle everywhere I go but I can still go places.

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