D31S Final Drive Repairs.

[JimInOz]

Hi Tony,
I just worked out that I might be able to fit the pinion/flange assembly in one piece.
The flange has a hole in it ,that will allow me to get to the retainer bolts,which was my worry previously.Will have a go at it tomorrow.

When I pulled this apart,the Komatsu fitters had been in there to inspect it for quotes.They left a few things out,thinking they would immediately get the repair job. So my assembly is a bit different to the dismantle job I did a while back.
One thing I did was to take lots of pictures during disassembly.I recommend this to any novice tackling a job they may only do once or twice.
Thanks again Tony.
Hope you are keeping busy over there...

Jim

[tctractors]

Hi Jim, the thing to do on the pinion thing is try to fit it in all built up loose, that is all the component parts but not pressed together, if it will fit then press the pinion into the flange with a simple shop style press and the jobs good, I always torque set the nut or bolt holding the flange to the pinion after the final drive is all back together, its just my way??.
The Firm "me" is still fairly active, been working on an I.T.L. shuttle gearbox today, thats a manual speed box with a F/R shuttle, I have a few jobs on the go but things are slowing up a good bit, lucky for me I have some big tasks ahead of me for the new year that are months of work that are not suffering any Euro rubbish, the customers are "Money Made" and never start something they cannot finish, so as my old Dad would say "never worry about work, cos the rich dont want it, if it was any good they would have the lot"
God Bless tctractors

[JimInOz]

OK ,I'm back onto this machine again,after another long diversion.
Tony,thanks for your insight.I really enjoy reading about your repair work & how you solve problems in the field.Thanks also,to the other guys who advised me along the way...
I have sourced good Jap bearings,new final Housing gasket & Sprocket seal.

At the moment,I'm about to SHRINK FIT the bearing onto the Bullgear shaft.

D31S Final. (1).JPG

I've never had to do this job ,& have been advised that I can "boil" the bearing in oil,to heat it up,before pressing it onto the shaft.
Is this the best way,or are there better ideas for a non-professional workshop.
I've heard about liquid nitrogen,but not sure about that option either.

Any suggestions & fitting tips are most welcome.

Thanks,
Jim

[Jeremy Rowland]

Hi Jim we shrink fit plenty of bearings where I am currently employed and they use a bearing heater to fit them, and usually use liquid nitrogen to freeze the shaft before the warm bearing is put in place, I appreciate that you don't have a bearing heater I would say the trick here is to gently heat the bearing so yes I guess you could put the bearing in some heated oil.

As for the liquid nitrogen you would need to contact a cryogenic contractor they will best advise you and give you an idea of cost too, hope that helps you.

Jeremy

[Julian]

As for the liquid nitrogen

An alternative would maybe to use a CO2 fire extinguisher, the dry-ice it emits is an effective coolant.

Julian.

[JimInOz]

Thanks for the tips...
So,once the bearing is warm,do I need to get it pressed onto the shaft in quick time? I imagine it needs to be fitted within minutes...
I have an old fridge in the shed...thinking of putting the shaft in that for a few days . ..just to keep it cool as I can.
I was going to take this part of the job to a shop & get it done,as I'll also need to fit shaft,bearings & housing together.There is a special jig used by Komatsu Techs for this,but I'm hoping I can stumble through it. I'll give it a shot for myself.

Jim

[tctractors]

Jim, your parked up in a hot part of the globe, so the freezer/fridge will do a good job of chilling things, on the bearing heat up job I use propane-oxy cutting set put on a very mild flame, hang the bearing on a thin bit of bar, then heat up enough to make spit sizzle, all that boiling oil crap is dangerous and not worth the trouble, just use your brains and heat the big metal bit of the bearing only, then with gloves on and a bit of speed place it onto its location, you dont need any Cryogenic stuff on this little banger, just a soft steel/iron drift and a good hammer and the job is done, I must have done well over a 100 F/Drives on track type tractors using the above method with no trouble, all that cryo freezing and boiling is time wasting and risky to bits that are part of your body.

[JimInOz]

Hi Tony,
I tend to treat bearings with kid gloves,& didn't realise that you could safely heat them up like that.
Looks like both bearings are 2 piece type,so that makes life easier.The large bearing is a 2 part Spherical Roller type & the small bearing is a 2 part ball type.
This job is at the larger end of what I usually play with,but I'm sure it's about the smallest stuff you deal with.
I'm impressed with the heavy build of this old Komatsu.

Hope you are keeping busy Tony. Thanks again..

Jim

[tctractors]

Jim, I did check into heat damage to bearings with a local C'o that make and modify bearings like grinding the inner race (C1 C2 C3 etc) the damage done with a gentle flame is nothing, if you take it say up to Pale Straw colour in the heat scale, dont expect it to be good for owt' you are only taking its temp up enough to aid fitting, not melting it onto something, I have had a few people say "I would not do that" well I tell em "tough" then they see how easy the bearing fits sliding easily to its location with no hammer crap and no harm, I have worked with the Komatsu fitters from Japan, let me tell you they are Dog Rough, they dont even clean off the protective gunk on shafts and gears, they just press it all together and throw it into place, nothing is heated, the only thing I have ever used the Cryo man for is fitting of Dead shafts in 155 dozers, that was years back and the Cryo man was the local cattle freeze brander, who let me dip my thing in his foaming pot for a fiver.

[JimInOz]

Hi Tony,
I see what you mean....some gentle,even heat saves time & hammer stress.

I hope to get this part done in a week or 2. Been busy doing other stuff,but am keen to get the old girl moving. I have a few tree stumps to move ,plus a dam that needs cleaning out.

Jim