re-power or junk it?

Marcintosh · Mar 20, 2012

Howdy-I've been trying to find a place where I could ask about this. It seems this is a likely area :thumbsup:
I've got a 1970 JD500 Series B TLB. Sadly, as far as I can tell I've spun a main bearing. I'm not sure I was able to save it and haven't had the time to have a good look.
Has anyone done an in-frame bearing swap in one of these? Does anyone know if it's possible?
It's sitting, stuck in the mud right where I started hearing the knock so I'm not looking forward to it but I'll do whats necessary, just like anyone else would.

How would you figure out if the machine just isn't worth fixing anymore?
At 19k #'s it's worth quite a bit as scrap though I'd have to disassemble it first just to get it out. Not looking forward to that either, front counter is 3800lbs so it's gonna be a back breaker no matter which way it goes.

It's not going anywhere so if you have a moment but don't rush, I'd appreciate any ideas you might have on any of this mess I'm in. I'd hoped to get rid of it before it came to this. I was about an hour too slow

Thanks for your time,
M

20 20 · Mar 20, 2012

This is a tough one. I had an ole excavator that I really liked that blew the engine. Well I figured if it's going to be fixed it should be done right, by the time I got all the parts added up it was cheaper to say goodbye. How many hrs are on your machine? What else is worn and will need fixen before long? You could fix one issue and have another part go, the old nickle and dime pain, not counting down time. It comes down to how much does it need, what does the machine mean to you and it's overall worth.

Bob Rooks · Mar 20, 2012

Can you do an in-frame if it has spun a bearing? Seems to me you may want to grind the crankshaft too.

crazyal · Mar 20, 2012

If you drive around some of the back roads you'll find the answer to your question. You'll see things like tractors and dozers parked out in fields where they died or at best where they could be pushed out of the way. Of course the price of scrap steel wasn't as high as it is now.

I would wait until it dries out and see if I could get someone with a small dozer to pull it to a spot where you can work on it. Once there you can see about pulling the oil pan and get a good look at the crankshaft. Chances are it'll need to be removed and ground down. If it has deep grooves carved in it then it may be too far gone.

But if one bearing was worn enough to spin then there's other parts that should also be replaced. Bushings for camshafts wear and leak too much oil which drops the oil pressure. That drop could have cause a lack of pressure needed on the rod bearing. So if you don't fix it you may just spin another bearing sooner than expect.

A third option would be to sell parts off of it.

Oldtractorfixer · Mar 20, 2012

You normally can't inframe a spun main. That being said you don't have to replace every part in the engine either. You will need to pull the engine and grind or possibly replace the crank and bearings. Should have the line bore checked and possibly rebored. You will need to strip the block and clean it and replace the cam bushings. You may not need to replace the following parts unless you want to: pistons, rods, cam, tappets, anything in the head, fuel system parts. These parts would all be replaced in a rebuild but for light use will probably go a long time. At a later time you can do the head etc if they need it. I just did a search and found a JD500b on machinery trader for $14000. I would think that might make it worth fixing if you have any use for it. I am not sure what AG tractor that is the same as this but you might get a used engine from a tractor salvage yard.