John Deere 750 Tractor SPUN Front, 2nd and 3rd Bearings

Paul Campanis · Dec 21, 2022

On my John Deere 750 Tractor the oil pump housing broke and the engine failed.
We currently have the engine apart and it is sitting at a machine shop.

All four main bearings spun. The rod journals on the crankshaft look fine.
The Rear bearing was the worst effected but we now have a good rear main housing (diagram below).
So I think we are fine for the rear.
Diagram of Rear main bearing housing https://partscatalog.deere.com/jdrc/sidebyside/equipment/78833/referrer/navigation/pgId/17603698

Now I need advice please regarding the other three bearings since they all spun.

The 2nd and 3rd main bearings sit inside of holders
See here: https://partscatalog.deere.com/jdrc/sidebyside/equipment/78833/referrer/navigation/pgId/17538088
Do I need to replace these or could they be machined and fit with fatter bearings.

The Front Main Bearing rides inside of the block and it spun as well. How should I have the machine shop work the block? Is there an oversized bearing or sleeve made for this perhaps.

I have already spent over $2000 worth of parts and labor. Parts purchased are new oil pump, injection pump and engine rebuild kit.

So, I would like to resolve these issues without trying to find a used engine.

Thank you!

Hoss710 · Dec 21, 2022

If it were me I'd get the block line bored . I would either have the crank turned , or a new crank. as expensive as a new tractor is. I'd fix it up and get it running again if it were me.

Paul Campanis · Dec 21, 2022

Thank you Hoss710.
We are having the crank turned.
Thanks for the advice on Line boring the block. I just don't know if we can get a sleeve for the larger diameter needed for the front bearing. I have inquiries to that end.