H main bearings

Anonymous-0

Well-known Member
I'm preparing to re-babbitt the rods from my '41 H but the mains need it too. Has anybody done this? I melted out the old babbitt and the mains have a steel bushing that looks like it's pressed into the housings. I didn't want to heat the whole housing so I made a puller to extract the bushing on the RH. A real dumb-a?? move. I thought the bushing was moving but all I did was pop the end off the casting. Does anyone know how those bushings were put into the housings? They won't budge. I haven't tried heating the housing yet. Bushings are only about 1/16 wall thickness so I don't get why they're so tight.

Any hints or suggestions welcome.
 
Send the rods & main housings to an experienced babbit guy now, OR the whole tractor to the scrapper (china) real soon. In the first place pouring babbitt is quite hazardous & if their not done right theyre useless & need redone again.
Im not saying your incapable, just something that in my opinion takes lots of experience and/or apprentice to do correctly :)
If you can afford to screw it up and do it over- then go for it &have enjoy learning a nearly lost ART
 
I had a few of those cranks turned or built up and turned ? and then the machine shop fitted them with bronze bushings for the main bearings.
Center Automotive in Akron Ohio did this.
 
I know it"s a little off the subject, but I have a Brand new H crank here some where that I will never use, last I saw it it still had cosmoline on it...
 
Why not replace the bearings with a more conventional bearing? There's no rule that says the bearings need to be poured babbit.

Far as that sleeve goes... I don't know what you're looking at. Do you have a parts book that show the sleeve as a seperate part? Are you certain it isn't just a shoulder machined into the casting? If it is indeed a sleeve then what I'd do is take a measurement of the location of the sleeve and write it down so you know where the new one needs to sit. Then grind / cut a slit in it and pop it out. Then get accurate measurements of the bore. Measure across a few different places. Odds are it won't be dead round. If the bore is way out of round that's another story. Then buy new bearings (see below) for a light shrink fit to the bore. I don't know what diameter your bearings are but figure somewhere around 4" O.D. on your bearings? Close enough.... I'd shoot for .002 to .004 interference fit. Remember that your new alloyed up aluminum bearing Inside diameter will shrink a breath also so have it sized to the baggy side of whatever clearance you want to your crank. Myself... if the bores are round within say .002... I'd ask for a bore about .007-.008 shooting for the 8... over your crank journal diameters. After installation you'll be around .005-.006. I don't think you want to go any tighter than that on these old girls. Better to error to loose than tight. You can run these up as baggy as .012+ without any issue. Wouldn't go that high but just saying...

Pressing the bearings in would be good enough but a shrink fit would be nicer. So you toss your bearing in the freezer and heat up the casting. When you go to install be quick and accurate. If you miss the mark then you'll simply need to press the thing home. Guessing there's a oil hole that'll need lined up too? A pair of thick plates and a bolt through the middle could pull the bearing in. Might need to turn a shoulder on one plate if the bearing is recessed a bit.

I would call or e-mail these folks...
Manitowoc Motor Machining and Parts.

http://www.motormachining.com/html/john_deere_main_bearings.html

They make new bearings for these old tractors and I thought their prices were very reasonable.
You can still buy babbit... and wood bearings... and all sorts of antiquated materials but doesn't necessarily mean it's the best for the application.

Good Luck,
Bob
 
Mike:

To remove the pressed-in RH (Blind) main bearing, I have scored & cut through the bearing with a Sawzall metal blade being careful not cutting into the bearing housing.

I sent my rods to Paul's Rod & Bearing (Russ Schworer 816-587-4747) for rebabbitting.

For the mains, I ordered new press in bearings from Sharp's Antique Tractor Works In MO.

I then had my local auto machine shop turn the crank main & rod journals then machine the rod & main bearings to 0.002" > the machined crank rod/main journal dimensions....It's a little tricky with the right hand bearing being blind...

Hope this helps.....Good Luck!
 
It was in with some parts I got years ago, at first I didn't know what it was (they are a bit unusual) I have a 41 H thought it may be good to keep,but I will never use it I'm sure..It is brand new..
 
When you sawed those bushings, did they come out easy or was something else holding them? I'm going to try some heat on the housings and maybe some kroil, but if they're that tight it may not penetrate. I was a tool and die maker for 20 yrs and another nine in tool design, so the machining and fixturing is no problem for me. As far as the babbitting goes, It's not a lost art but rare, and I just want to try my hand at it. I've already made a mandrel for the rods, researched babbitt procedures and contacted the JD historical to get the proper grade of babbitt.

Thanks for the input.
 
Mike:

It has been a few years now, but I think the RH main bearing cane out easily once cut...I may have made two cuts....I did not have to use heat.

For the con rod bearings, I assume you are working on an H after S/N 21500. Pre 21500 tractors had shell type automotive type bearings & 21500-on tractors had "spun-babbitt" bearings that have adjustable clearance by controlling shims in the rod bolts.
 
Just wondered if it came from the old Killbuck Eq. When they had a sale. They had boxes and boxes full of goodies.
 

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