Layshaft bearing again

Paranoia finally got to me and the thought of going down the road sideways with a locked up gearbox did not appeal!
Gearbox stripped down in situ with no problems but the layshaft complete with bearing came out with no effort at all, and it looks like it's been doing a dance in the casing! When the old bearing (Not the nasty Portuguese type so it could have stayed there) is refitted it's not slopping about so the new roller bearing might just need some bearing loctite to keep it tight (JB Weld maybe?) Has anyone had this and what was your particular remedy?

Loctite bearing fit!

From old britts

"If your bearings were loose in the case when you removed them, you will have to use Red Loctite or Sleeve Retainer to make sure they do not rotate in the case (see Loctite for information and prices). I make it a habit to Loctite the bearings in the gearbox shell, but do not worry about the bearing in the inner case, for it does not seem to be a problem. I apply the Loctite to the outer race of the bearing, making sure that I do not slop any into the bearing."

willy mac said:

(Not the nasty Portuguese type so it could have stayed there)

Click to expand...

Any (steel/brass cage) ball bearing is likely to break up eventually, not just the Portuguese bearings, so is still a job worth doing.

kevbo82 said:

From old britts

"If your bearings were loose in the case when you removed them, you will have to use Red Loctite or Sleeve Retainer to make sure they do not rotate in the case (see Loctite for information and prices). I make it a habit to Loctite the bearings in the gearbox shell, but do not worry about the bearing in the inner case, for it does not seem to be a problem. I apply the Loctite to the outer race of the bearing, making sure that I do not slop any into the bearing."

Click to expand...

So no need to heat up the casing to re-insert the new bearing then?(unless the new bearing's OD is just that tadge bigger) Just glue it back in place and we're good to go?(After shimming that is!)

willy mac said:

So no need to heat up the casing to re-insert the new bearing then?(unless the new bearing's OD is just that tadge bigger) Just glue it back in place and we're good to go?(After shimming that is!)

Click to expand...

Here is the rest of the assembly article from old britts, I didn't buy the Mick Hemmings DVD so this page was my bible while rebuilding (along with this site) some guys also stick the bearings in the freezer for a few hours for a drop in fit

http://www.oldbritts.com/gearbox_a.html

I had a lot of grief pulling the layshaft bearing out of the case, even after heating it up in a gas grill. Maybe I didn't heat it up enough? Anyhow, I made a simple puller out of some long small bolts and finally pulled it out with the heat. I did that on mine and sidriley's.

The main bearings in the crank cases pretty much fell out in the same gas grill.

Just an observation.

I wonder if someone could give us a max temperature that can be used on the AL cases. I have a good Fluke meter with the thermocouple that will measure well over 500 deg. F. I even put it on the wood stove that was getting red hot one winter and as I remember it was around 550F. I don't think I want to get the AL cases red hot.

Dave
69S

DogT said:

I had a lot of grief pulling the layshaft bearing out of the case, even after heating it up in a gas grill. Maybe I didn't heat it up enough? Anyhow, I made a simple puller out of some long small bolts and finally pulled it out with the heat. I did that on mine and sidriley's.

The main bearings in the crank cases pretty much fell out in the same gas grill.

Just an observation.

I wonder if someone could give us a max temperature that can be used on the AL cases. I have a good Fluke meter with the thermocouple that will measure well over 500 deg. F. I even put it on the wood stove that was getting red hot one winter and as I remember it was around 550F. I don't think I want to get the AL cases red hot.

Dave
69S

Click to expand...

http://www.harborfreight.com/blind-hole ... 95987.html

DogT said:

I had a lot of grief pulling the layshaft bearing out of the case, even after heating it up in a gas grill. Maybe I didn't heat it up enough? Anyhow, I made a simple puller out of some long small bolts and finally pulled it out with the heat. I did that on mine and sidriley's.

The main bearings in the crank cases pretty much fell out in the same gas grill.

Just an observation.

I wonder if someone could give us a max temperature that can be used on the AL cases. I have a good Fluke meter with the thermocouple that will measure well over 500 deg. F. I even put it on the wood stove that was getting red hot one winter and as I remember it was around 550F. I don't think I want to get the AL cases red hot.

Dave
69S

Click to expand...

That article on old britts said 300-350 in the oven. I used a propane torch and the mick Hemings method of spitting on it to test doneness (which doesn't work as well in the kitchen...)

Spitting is not my idea of temperature testing. I'm sure Mick has many hours of doing it and he knows, but for us commoners that don't have 80 hours of experience, it's not enough. Just my take.

Actually the puller I made worked fine, I put it in a bag and put it in with my other bag of tools, I'm sure some day when the other half sells the stuff, some one will look at it and wonder what the hell this thing is for and it'll be thrown out. I've got a lot of stuff like that.

I also work on antique tube (valve) radios and have a lot of esoteric equipment and jigs that no one in their right mind would ever figure out what it is. That's life. If you like look up 'mechanical filters' on wiki,I repair them. I thought it was impossible but it's amazing what you can do with a bit of anal persistence. You can look at my work here as a side option from the Norton. http://s251.photobucket.com/user/DogTi/ ... t=3&page=1

I hope I'm not preaching.

Dave
69S

Just heat the goddamn snot out of the shell upside down until the stoopid ball layshaft bearing drops out. Spit test good. Flip it over with BIG leather gloves and drop in the Frozen new roller bearing. Tap bearing inner onto layshaft. Reassemble with new sleevegear bushes and 1 st gear bushes. Freeze those too. Cold is your friend.

yeah spit worked just fine for me. Once it was hot enough to sizzle my flem i pulled on the layshaft and the bearing came right out with it.

DogT, my brother has a couple old zenith consoles from the 40's i had to get running again (just replacing a few tubes and leaky caps, i'm no expert) we even rigged an ipod and sonos unit into the one to replace the phono so purists like yourself could curse my name! :twisted:

As stated if bearing in as tight as designed - must heat the smoking oil out of it till race either falls right out or with a thump on wood. Heating the shell or even engine case to over oil burning temps 7-800'F does no harm to them as long as whole thing heated up that hot. Famous Nortoneers known the loctite is a joke and worse than waste of time to hold tranny or engine bearing stable at operating temps vibes and loads. Ask Fred and he may tell ya the site advice there has not been updated in a few decades. Hi temp JBW or low temp solder is about only glue in method that will work or stacking by a machinists. Bore and race surface should be roughened for these to get a grip on or may still spin again.

hobot said:

As stated if bearing in as tight as designed - must heat the smoking oil out of it till race either falls right out or with a thump on wood. Heating the shell or even engine case to over oil burning temps 7-800'F does no harm to them as long as whole thing heated up that hot. Famous Nortoneers known the loctite is a joke and worse than waste of time to hold tranny or engine bearing stable at operating temps vibes and loads. Ask Fred and he may tell ya the site advice there has not been updated in a few decades. Hi temp JBW or low temp solder is about only glue in method that will work or stacking by a machinists. Bore and race surface should be roughened for these to get a grip on or may still spin again.

Click to expand...

Yeah what he said and i'll add. Just like all bearing bores aren't the correct interference fit they should be, you can't assume all worn bearing bores are the correct size to work with bearing retaining loctite, jb weld or bunch of center punch dings. Anything more than .001" loose fit should get a sleeve repair.

Yeah, well to translate hobot'enese, if engine or transmission bores are even questionable loose issue of spinning the races, then loctite absolutely still will not retain them from spinning > as any and everyone ever tried it reported sooner or later finding. Not my opinion, just repeating what I read and learned over the years from those whoose simpleton hopes were dashed. How bad can the bores get before its much an issue on non raced Commando.

JBW is really just a hardening in place agent not an adhesive so I'd not even trust it when heated and vibed and oiled to stablize w/o some decent texturing of both surfaces and even then would not trust it past my drive way until it set up 3+ days and heated to well over anything it'd see in usage. I am handy with JBW saving my cold weld bacon but also know its downsides and heat softening is a biggie and thin layers cracking is another. To remove a well JBW'd in race you'd heat it to 500'ish F to get it back to honey like, if using the 600'F rated original version. Judging amount not to get back side pile up into race might be tricky though oiling that part 1st would be wise. I know JBW ways so much I shudder to use it for this and can't bring myself to do it, in case that worries ya to read. Comstock does it. Ugh crumble dusts in the cogs comes to my mind if it fails to hold.

I'm thinking more like Inca did, make cuts in two stone facing each other and pour or beat metal into the space locking joint in place. Get some 400-ish F melt metal and pour in 2-3 notches in race and bore. After all the alloy welding Peel's had done, feet of it, I no longer think 500-600'F is getting cases very hot any more, so the metal will flow out like hot water followed by the bearing. But as its locked in place, removal should be delayed to next generation.

Hi,

If you are having trouble with removing the layshaft bearing after heating - it may be that you are heating the alloy section too slowly. This allows the steel ball race to expand at a similar rate to the alloy. The alloy must be heated quickly so that it expands faster than the transfer of heat to the the steel bearing. it is during this period that the steel bearing can be extracted with little mechanical effort.

There is a great set of you-tube clips on rebuilding an "MZ 250 etz" engine that exemplifies the use of heating and cooling bearings for trouble free rebuilds. Although the rebuild has obviously been pre prepared, a friend and I have just followed the examples and voila - no heavy pressing, no hammering, just perfect fits for every bearing removal and re fit.

regards
Tyborg

Even if heated slowly if heated enough the alloy will out expand the steel every time. About only thing that can trap the bearing is if seated crooked which is not the case if was actually in use prior. I used to be heat timid as most of you so only heated into 300'F range to have bearing get cockeyed and absorb heat out the shell so bearing expanded and shell contracted ugh, then took oil smoking into 500'f to free it again, with hard thumps on wood. Can place in oven so bearing and shell same heat and bearing should just tip out. So to me the issue is can I get the thing hot enough w/o wasting time and gas. Heating alloy to near its melting point is a way to destress it not damage it.

I agree, if it's a bugger to drop out ( thats good because you want tight) then hit that P.O.S. bearing with an icecube ,it'l drop out. Use BIG leather welder's gloves cause things are gonna be hot.

Well, I put the 2 GB I did it a little gas grill I had around and got it up to maybe 400-450F and it wouldn't drop or come out with a whack on the wood, so I ended up pulling them. I guess if I do it again, I'll let it heat up some more. But like I say, same temp for the crank cases they just fell out on the grill, just like the movies.

Dave
69S

I have not been in the gearbox so don't know if this would even apply here, but in the April Classic Bike they show someone TIG welding around the circumference of a crankcase bearing race to cause it to shrink, and allowing it to be lightly drifted out. I'm not understanding the logic of that as I would have thought the race would expand.
Brendan