Author Topic: Drive side main bearing inner race removal  (Read 719 times)

Offline Steverat

  • Valued Contributor
  • ****
  • Join Date: Aug 2018
  • Posts: 251
  • Karma: 1
Drive side main bearing inner race removal
« on: 16.10. 2018 20:41 »
Difficult! I have several pullers but nothing with long enough reach, and even if they did I couldn't get them between the race and the face of the crank. Any ideas what to do without investing in expensive equipment?

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS

Online RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 504
  • Karma: 4
Re: Drive side main bearing inner race removal
« Reply #1 on: 16.10. 2018 21:10 »
Whenever I've had a ball / roller race that's a problem, I've done the following:
Remove outer race and balls / rollers - easily smashed with a sharp blow from a hammer if it doesn't come apart naturally. Wear protective glasses.
Heat the inner race in one spot quickly - ie with oxy acetylene. The idea is to get part of the inner race red hot without getting too much heat onto the shaft.
With a sharp cold chisel, give the red hot area a sharp smack. This will expand the inner race so it'll slide off even after it cools.

I forgot to add: the bearing should be a push, not a press fit on the shaft. It should be able to be fitted with only very light persuasion. Remember the new bearing has to be removed after fitting to shim the crank, so you don't want to have to wreck that as well. If the shaft / bearing fit is too tight, clean the shaft with emery. The cush drive nut is what holds it tight.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Offline Swarfcut

  • Resident Legend
  • *****
  • Join Date: Oct 2018
  • Posts: 700
  • Karma: 9
Re: Drive side main bearing inner race removal
« Reply #2 on: 17.10. 2018 09:22 »
 Steve...worth investigating local tool hire for bearing pullers.   Have a look at Machine Mart. Not the cheapest, but good range of options. Once the bearing is off and your crank is sorted ready to be reinstalled, you have the delights of setting the crankshaft  end float, a theoretically simple operation which has brought many A10 owners to the edge of insanity, me included. There is more than enough information elsewhere on this Forum.

 Swarfy

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 5537
  • Karma: 29
Re: Drive side main bearing inner race removal
« Reply #3 on: 17.10. 2018 09:42 »
the delights of setting the crankshaft  end float...
This was me six years ago

Offline Steverat

  • Valued Contributor
  • ****
  • Join Date: Aug 2018
  • Posts: 251
  • Karma: 1
Re: Drive side main bearing inner race removal
« Reply #4 on: 19.10. 2018 00:18 »
We finally got the old inner race off the shaft mostly by cutting it with a slitting rotary cutter.

The next message is obviously that I now have to find a way to pull the inner race on and off the shaft several times without destroying it, in order to adjust the endfloat! Do you have any tips for me?

Steve

1951 BSA A10 - now returned to Germany
1972 Triumph T100R Daytona
1924 B-S SS80
1965 Triumph SH Cub
1960 AJS M18CS

Offline berger

  • Resident Legend
  • *****
  • Join Date: Nov 2017
  • Posts: 802
  • Karma: 5
  • keith from chesterfield 500ss cafe morris 8
Re: Drive side main bearing inner race removal
« Reply #5 on: 19.10. 2018 01:18 »
you might *smile*be lucky if you clean the crank shaft up  find a new bearing will slide on and off providing you offer it up very square, the only time I got one stuck it was a japanese made race that must have been very slightly different even though the supplier said it was the same but  made in japan.  the SKF that I fitted  snuggly slid on and off. the only tip I can give is don't eat yellow snow *bash*

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 5537
  • Karma: 29
Re: Drive side main bearing inner race removal
« Reply #6 on: 19.10. 2018 08:25 »
I was able to shift my main bearing by using an old wood chisel to get it moving, then a tyre lever. I have some levers from an old Volvo tool kit, they are really useful! Used the same method when setting endfloat.

Online RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 504
  • Karma: 4
Re: Drive side main bearing inner race removal
« Reply #7 on: 19.10. 2018 12:36 »
Steve, I wouldn't have risked a disc cutter. Awkward place to get and a high chance of nicking the shaft, which would then cause a fracture point. Re getting the bearing on and off, like I said in an earlier post, the bearing needs to be a push, not press fit. If it is tight, clean up the shaft with emery until it is a light push fit. Then you will have no problem.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 4918
  • Karma: 45
Re: Drive side main bearing inner race removal
« Reply #8 on: 19.10. 2018 13:17 »
We finally got the old inner race off the shaft mostly by cutting it with a slitting rotary cutter.

The next message is obviously that I now have to find a way to pull the inner race on and off the shaft several times without destroying it, in order to adjust the endfloat! Do you have any tips for me?

Steve


If you had the old inner race you could have ground out the ID a touch to use it as the test race. I din't think you should try to reduce the shaft diameter with emory, or any other way. When installing the new bearing for good, freeze the crank and bake the race. You could get over to the topic "Home Made Tools" and see a couple of different pullers, including mine. While puller force us applied you hit the race with a propane torch and it should come off.  I'll share the link with the pullers when I am not thumb typing. If you end up with a loose fit of the inner race, you can use Loctite bearing retainer, clamping  the race and shim stack against the web with the cush nut and spacers while the Loctite cures.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Offline berger

  • Resident Legend
  • *****
  • Join Date: Nov 2017
  • Posts: 802
  • Karma: 5
  • keith from chesterfield 500ss cafe morris 8
Re: Drive side main bearing inner race removal
« Reply #9 on: 19.10. 2018 14:22 »
aha Richard I tried that method of old inner race to get end float correct and it came back and smacked me in the face *problem* because I had the new outer in the crankcase there was a difference,[ not very much but enough] between the outer races and where the inner races sat in the outer races even though they were the same number. so to use this method you will have to carefully do bearing measurements with our friend mic and get the maths head on *pull hair out* hence I cleaned the crank until as RD fella says it was a nice push fit , after all this race is or should be clamped tight up to the crank web------ ok enough of this I am racing off to the barley pop shop cheers *beer* thanks for listening byeee *wink2*

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 4918
  • Karma: 45
Re: Drive side main bearing inner race removal
« Reply #10 on: 19.10. 2018 15:00 »
I cleaned the crank until as RD fella says it was a nice push fit..."

I'm open to being corrected (and, somehow, expect to be), but I think if you can push it on by hand it's too loose, Mr. Lautrec.

Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 504
  • Karma: 4
Re: Drive side main bearing inner race removal
« Reply #11 on: 19.10. 2018 15:26 »
A push fit does not mean it is loose or slides easily. It means a light force is required to fit the item. Maybe by hand, but usually requiring a gentle tapping for persuasion. A press fit requires a greater and varying degree of force depending on interference, certainly a hammer and drift or a press. The point with the bearing in question is that if it requires a lot of force to fit (ie a press fit) then something - certainly the shims - will be damaged when it has to be dismantled. Probably the bearing too, if it required driving on with a hammer and tube or in a press. And a press will distort the crankshaft unless it's carefully supported. But there's no need for that grief because the cush drive nut holds the bearing tight so, as long as it's not a rattling fit on the shaft, all will be fine. At least that's what a few years as a toolmaker and fifty odd years in mechanical engineering taught me.

I forgot to add:
When a bearing is a press fit, it closes up or expands by roughly half the interference. Therefore, when you have a ballrace or roller bearing that’s an interference fit on the outside (as ours are) and a press fit on the shaft, there is every likelihood the bearing will have lost its running clearance. In which case an extra clearance bearing should be used – such as C3.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online RichardL

  • Outside Chicago, IL
  • Wise & Enlightened
  • *
  • Join Date: Nov 2007
  • Posts: 4918
  • Karma: 45
Re: Drive side main bearing inner race removal
« Reply #12 on: 19.10. 2018 15:56 »
RD,

For "off," I suggested heat with a puller. For "on," I suggested cold on the crank and heat on the bearing. Maybe this fits your description of gentle persuasion, but experience with this bearing on my bike tells me it can't be gently persuaded off the shaft if the fit is right and tight. When dismantling with a puller, you need a puller that avoids the shims. This is what I tried to accomplish with my crude home-made puller, which has worked successfully several times now, despite its shortcomings.

Now. it might be that the cush nut is supposed to hold it all tight, but there are plenty of cases of wasted shims here that are not all due to a loose cush nut, I think.

If the following pictures come through, I have a feeling I will get some admonishment from a real toolmaker.


Richard L.
Plan on signing up for the world-wide 2017 DISTINGUISHED GENTLEMAN'S RIDE on September 30, 2018. Watch website at https://www.gentlemansride.com for details.

Online RDfella

  • Resident Legend
  • *****
  • Join Date: Aug 2017
  • Posts: 504
  • Karma: 4
Re: Drive side main bearing inner race removal
« Reply #13 on: 19.10. 2018 17:04 »
Neat job Richard. Dunno if several years in a toolroom making precision dies (punch and injection moulds) qualifies me as a 'real' toolmaker but I can't really fault your puller. Only difference I'd have made would have been cross-bolts rather than straps. That way, with a countersink on the plates, the puller could be forced in behind the race.
Only part I don't understand is it seems you have it where it should be - behind the inner race and not on the cage - but surely that involves damaging the shims to get it there? The whole point of my argument is that at some stage one is going to have to pull the new bearing off to place shims, so why give oneself a load of grief when it's not necessary?
As for the cush nut / shim argument, that's been covered in depth elsewhere on this forum. Suffice to say if the bearing is held tight to the crank web, no harm can come to the shims. It can only happen if the bearing inner race moves and I suspect tightening the nut with a spanner (as some do) when there's no safe way of locking the engine may well be the cause of failures. I recall when I first started with BSA's in the early 60's the main dealer warning me to do the cush nut up 'bloody tight' or else the crank would disintegrate (the singles are the same set-up but the mainshaft is riveted to the flywheel). In 50 + yrs of riding on the road and c. 20 yrs of racing, I've never had one come loose. And I don't bother with a split pin. What's the point? If the nut comes back that far, the crank is already damaged.
'49 B31, '49 M21, '53 DOT, '58 Flash, '00 Firestorm, Weslake sprint bike.

Online Greybeard

  • Jack of all trades; master of none.
  • Wise & Enlightened
  • *
  • Join Date: Feb 2011
  • Posts: 5537
  • Karma: 29
Re: Drive side main bearing inner race removal
« Reply #14 on: 19.10. 2018 17:32 »
I would say that my old and new bearings were a push fit. I didn't have any real trouble  *bash* (this is Richard and others bashing me over the head for being a smug git!)