L&R Master Question: Motor Housing Removal

[WhaleWatchM7]

I picked up an L&R Master that needed an overhaul a few weeks ago and have been slowly disassembling and cleaning it, but I've hit a snag: I can't get the motor cover to separate. I've removed the retaining ring from the motor shaft, the setscrew from the side of the housing, and all the screws from the underside of the motor housing. When I first tried moving the lower housing, it was stuck tight--no rotation and no ability to pull it straight out. After attaching a temporary handle to the lower housing with the existing screws, I got enough leverage to get the two pieces to wiggle, but the housing still won't separate. 

I've watched a few videos of people restoring these units, and those who bother servicing the motor are able to wiggle the housing halves a bit and then just pull them apart. Anyone with experience with these units have any advice for next steps I could try? Heat? More leverage? Judiciously applied dead-blow hammer? My goal is to do this, of course, without damaging anything.  Given how brittle every wire in this unit seems to be, I want to get the motor apart and replace the power cord as close as possible to the coils. Thanks!

[tomh207]

My first thought would be to try a car oil filter wrench to get grip and leverage to avoid damage. It would be worth using magnification to examine the seam to see if glue/paint/gunk is filling the join and making it difficult to release.

 

Tom

[WhaleWatchM7]

Thanks @tomh207. I've now tried the wrench, and the housing does move maybe a quarter inch side to side but hits a hard stop at either end of the travel. So it doesn't seem to be gunk build-up. And I'm not seeing any separation at the seam. Going to get another wrench and try working with two of them on either side of the seam to see if that gives me enough leverage to make things come apart. 

[LittleWatchShop]

I have done a few of these...one very recently. Please show pictures of the bottom.

The set screw holds the stator and has no role in holding the two halves together, but it is ok to remove it.

There is a bearing race that mounts at the top. Usually it separates from the housing, but not always. I have never tried this, but you might heat the top and see if it releases.

I cannot recall if the two halves have freedom to rotate a full 360 degrees. Probably not. Could be a hard stop based on design.

I feel confident that you need to break the bearing race loose. Be careful. If you decide to do some tapping with a hammer, use a rubber mallet or jewelers leather mallet.

Edited March 5 by LittleWatchShop

[WhaleWatchM7]

@LittleWatchShop. Photo attached, thanks. I contemplated a few dead blow hammer taps but definitely don’t want to damage anything. It feels like I’m missing something obvious and simple. 

[LittleWatchShop]

I am certain that the bearing has sized to the upper housing. Try wiggling the post back and forth while pulling.

Also try the heating idea

[WhaleWatchM7]

@LittleWatchShop Success!  I applied a little heat with my gun and used my bearing splitter under a couple of the housing screws, and it came apart like a charm. No beating necessary. The bearing was definitely frozen to the back of the housing. Thanks for the help!

[LittleWatchShop]

Hey that bearing splitter is pretty cool.  I will be on my way to Harbor Freight next week to get a set!!

[WhaleWatchM7]

Yeah, it worked perfectly. The smaller splitter was *just* wide enough, but I feel like I can make my own custom add-ons down the road if I need something odd sized. Well worth the money. 

[WhaleWatchM7]

And now a new issue: the rotor won’t come out.  It spins, but it seems attached to the top of the housing. Another situation for the bearing splitter or is there a better solution?

[HectorLooi]

Not the bearing splitter but a bearing puller or bearing press. A pretty long one at that.

Clamp the legs of the puller around the housing and tighten down the screw on the spindle and push out the rotor. Much safer than using a soft face hammer to tap out the rotor as what many repair shops would do.

[LittleWatchShop]

Same issue as before.  The bearing is seized in the top of the housing. Now, you have some room to wobble the armature back and forth.  Should be good enough to break free.  OR...pour a copious amount of penetrating oil into the housing and let it sit a day or so.  Kroil, for example.

[WhaleWatchM7]

I managed to safely remove the rotor from the bearing, but the bearing remained stuck in a blind hole, so I tried the old bread trick, and it worked!  Physics--it's not just for physicists!  The bearing were pretty bound up, and rather than try to repack 75-year-old bearings, I've ordered a couple replacements.  

[LittleWatchShop]

I've got those bearings if you need a source

[WhaleWatchM7]

@LittleWatchShop I'm all set, thanks. They seem to be pretty standard, so I ordered some Ezo bearings off the Bay. 

[LittleWatchShop]

Be sure to post how you do the install!!

[WhaleWatchM7]

@LittleWatchShop I've been thinking about that, actually. Any advice?

For the one in the top housing I was going to use my arbor press and a disk sized to fit the outer edge of the bearing--poor man's bearing press. I have some dies from a cheap watch case closer, one of which is an excellent fit to the bearing.

Then I was thinking about using the bearing puller to pull the other one on to the long end of the motor shaft down to the point where the old one was living.

Then I'm a bit stuck. I've contemplated using the case itself as a press--lining everything up and then using the housing screws carefully, turning bit on each side, to close the case and insert the bearings at the same time. 

I'm always open to suggestions!

[LittleWatchShop]

13 hours ago, WhaleWatchM7 said:

@LittleWatchShop I've been thinking about that, actually. Any advice?

For the one in the top housing I was going to use my arbor press and a disk sized to fit the outer edge of the bearing--poor man's bearing press. I have some dies from a cheap watch case closer, one of which is an excellent fit to the bearing.

Then I was thinking about using the bearing puller to pull the other one on to the long end of the motor shaft down to the point where the old one was living.

Then I'm a bit stuck. I've contemplated using the case itself as a press--lining everything up and then using the housing screws carefully, turning bit on each side, to close the case and insert the bearings at the same time. 

I'm always open to suggestions!

Definitely do not use the case!!

I have yet to do mine, but I have read where people put the armature in the freezer and then heat up the bearing before slipping it on. I will probably do that. I may also take some 1000 grit sand paper and remove some of the arbor surface...at least toward the long end-- the bearing only needs to fit tight where it is seated.

[WhaleWatchM7]

Ahh, thanks. The heat/cold option sounds like a good one--will have to figure out the best heating option. Now that YouTube has presented me with "induction bearing heaters" it makes me wonder if an induction cook-top might do the trick or at least be worth an experiment on an old bearing. 

https://www.practicalmachinist.com/forum/threads/induction-bearing-heater-idea.314565/

[HectorLooi]

Do not heat the the bearings. The heat can affect the temper of the bearing steel and also melt the packing grease inside the bearings.

The motor shaft needs to be clean and rust free. Sandpaper and steel wool would do an adequate job. You will need a pipe that fits over the shaft loosely to tap the new bearings into the bearing seat. Watch the video below for a clearer explanation. 

 

[mbwatch]

On 3/11/2024 at 6:02 PM, WhaleWatchM7 said:

so I tried the old bread trick,

The WHAT?

Well okay, today this place taught me one can drive seized automotive bearings out with a hammer and bread.

[LittleWatchShop]

Today, I bought the Harbor Freight tool. It worked to remove the bearings. Needed a little help though.

I used it to install the bearings also. I think I damaged them. I need some washers that snugly fit the shaft so that the tool exerts pressure in the inner race

Edited March 17 by LittleWatchShop

[LittleWatchShop]

12 hours ago, LittleWatchShop said:

Today, I bought the Harbor Freight tool. It worked to remove the bearings. Needed a little help though.

I used it to install the bearings also. I think I damaged them. I need some washers that snugly fit the shaft so that the tool exerts pressure in the inner race

Success.

[LittleWatchShop]

On 3/13/2024 at 4:37 PM, WhaleWatchM7 said:

Then I was thinking about using the bearing puller to pull the other one on to the long end of the motor shaft down to the point where the old one was living.

That is what I did. However, you must flip it. Also you need to find a washer that interfaces to the center race so that the puller pulls on the washer and not the outer race.

I ruined my first attempt because I had the puller grabbing the outer race.

[WhaleWatchM7]

6 hours ago, LittleWatchShop said:

That is what I did. However, you must flip it. Also you need to find a washer that interfaces to the center race so that the puller pulls on the washer and not the outer race.

@LittleWatchShop Thanks for that advice!  I'm going to give it a go this weekend and will keep that in mind.