Removing Press Fit Jackshaft Bearings

#1
News-Flash!!!!

...Getting ready to ship this Bonanza 1300 frame to Smallbore ..the jackshaft bearing were toast so I decided to take them out (save on shipping weight :laugh:) and use the opportunuty to show Kk jr. a trick or two.

Of course this may be old hat for the seasoned veterans....so you smarty-pants' can change channels now...this is for the folks who may be tackling it for the first time or who have struggled with it in the past.

Now's a good time to spray the area with some penetrating oil...grab a cup of your favorite beverage and psych yourself up for the job at hand.....

The bearings are a press fit in the frame....no retaining groove/clip ....but to try and beat them out is a mistake, especially after all these years those baby's are really stuck...you run the risk of bending the flange or distorting the hole...:doah:...you could use "heat"...but maybe you don't want a flamed paint job or you think the bearings can be re-used.....there's an easier way...."press" them out.



The thing to remember here is you want to press on the outer bearing race to remove or replace a bearing of this type...never press on the center or inner race, especially if you are planning on re-using the bearing.....if you apply force to the inner bearing race you will destroy the bearing !!!

Start by rounding up a piece of 1/2" threaded rod, some heavy washers and two nuts....



On the outside you need "cup" that is slightly bigger that the O.D. of the bearing...it should be made of steel or aluminum or any material strong enough to withstand the force that is to be applied....I don't recommend wood or plastic.

I have some fancy ones I made over the years of turned aluminum but I'm gonna use just a pipe fitting here just to show you can use whatever you might have on hand. Even a short length of black pipe or a "close" nipple will work, as long as it is perfectly "square" ... by that I mean flat and parallell on the ends. Don't use a piece of tubing or pipe that is crooked or tapered on the ends...The idea here is to provide strong even support around the outside of the bearing yet allow room for the bearing to press out. You will also need a large diameter, thick washers or piece of steel with a 1/2" hole in it to cover the end.
On the other (inside) you will need a piece of round stock that is just slightly smaller than the OD of the bearing (1-3/8" in this case) ....this will also need to have a 1/2" hole in it for the threaded rod to pass through. An impact socket works perfect for this as they are usually heavy wall....a short one would be perfect but I'm using a deep socket....in this case I chose a 15/16" socket. (Measure the outside of the socket to be sure it's not greater than 1-3/8" because it has to pass through the frame). A socket also works well because it wont press on the inner bearing race as was mentioned above....many times the inner bearing race stands proud of the outer race so you want to be sure you are not pressing on this...you want to press on the outer race.

Ok assemble this whole deal as shown here...



use a heavy washer on top of the socket so the nut bears down on it....good idea to grease the threaded rod and nuts with some high pressure wheel bearing grease, never-seeze, etc...so it operates smoothly under load...run the nuts up by hand while keeping everything centered ..



..again make sure the socket wall or driver is bearing against the outer race of the bearing only....then get two long wrenches and start cranking on the nuts to draw the bearing out....some of these suckers are tight so be prepared to go at it in small increments...usually once it "pops" free it will start to move easier. When the socket nears the frame flange be sure it is still centered so it can finish pressing the bearing through and pass through the frame itslelf...

Presto....done and you didn't (hardly) have to use any bad words.....:rolleyes:



You can also use this same process in reverse to replace the bearings.....just be sure everything is clean and aligned straight before pressing them in...again...always press on the outer race only!!!

There is a chance the new bearings can be tapped in if you support the flange ....or maybe there are better ideas out there but this is how I do it.....:shrug:

Now back to our regular scheduled broadcast....



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george3

Active Member
#2
Presto....done and you didn't (hardly) have to use any bad words..... :laugh::laugh::laugh:. good info. you can use sub. parts but bacically the same thing.
 

Scottessey

Active Member
#3
Great tip, KK. :thumbsup: I used a similar technique to reinstall bearings after paint. Fortunately, my frame was rigid enough to not require a spacer in between the frame members.

 
#5
........ I used a similar technique to reinstall bearings after paint. Fortunately, my frame was rigid enough to not require a spacer in between the frame members.

yeah looks like Scott used 5/8" threaded rod (same size as axle) which is even better but sometimes hard to find at your local hardware store....and like he said his frame looks super rigid so he could "pull" both new bearings in at the same time without fear of distorting the frame....

>>>> also notice how he used a nice thick washer with a hole in it that's big enough to drop over the inner bearing race so it bears down on only the outer race...this is key!!! :detective:

....if the bearing plates had been of a lighter guage or further apart you could bridge between them with a length of pipe or bar stock to keep it rigid while you draw them in.....

Thanks for the added info, it's always interesting to see the different solutions people come up with...:thumbsup:



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Scottessey

Active Member
#7
....if the bearing plates had been of a lighter guage or further apart you could bridge between them with a length of pipe or bar stock to keep it rigid while you draw them in.....
True! You just have to make sure if you use a pipe in between that you can pull the pipe out after your bearings are in. :doah: :laugh:
 
#8
True! You just have to make sure if you use a pipe in between that you can pull the pipe out after your bearings are in. :doah: :laugh:
Yes should have mentioned that !!!:laugh:

or place the spreader bar directly above or below the bearing hole for support...if it's fancy-schmancy new paint like Scott's, use some tape or thin rubber pads on the ends of the spreader to keep from marring the finish.. :thumbsup:
 
#9
should also mention if you are painting or especially powdercoating you may want to leave the bearing holes in the frame bare metal....or the bearing will just fight you more when installing...if the bearings fall out of your bike you may want to purposely leave the powdercoating to help with the press fit.....get it :blink:
 
#10
As a kid I remember my friend's saying "you don't want to race so and so...he's got a jackshaft in his bike!!"" :eek:hmy:

I'd be like "No way...a jackshaft....really??!!"...."I'm not messin with him"...:blink:.

meanwhile the whole time I was thinking what the hell is a "jackshaft"..:shrug: I think I even went home and asked my older brother but that stoop didn't know anything..:glare:

I think it was only until I found the OldMiniBikes that I actually figured it out.....:laugh:
 
#17
How bout if you drilled and tapped the end of the jackshaft....say maybe 5/16-18 or 3/8-16....or weld a deep nut onto the end of it.....then thread a big ol' slide hammer into it and start slamming !

You'll want to soak things in penetrating oil for a few days prior....and find a way to hold the frame solid while you do it...but you should get the shaft and maybe even one bearing out this way.....
 
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