First do no harm (new oil leak at rear)

TO-30 Z129 engine.

Attempting to identify the cause of low oil pressure, I pulled the bearing caps to check clearance and also opened up the oil pump. Clearances were well within range, pump gears were quite sloppy. A pump rebuild is on the list now. I put it back together to use until I get the rebuilt kit ordered.

My problem. I now have a leak around the rear main seal that I did not have before. In reading the archives and also re-reading my manual (I-T shop manual) I suspect that I messed up the seal itself or more likely the packing along the rear bearing cap.

Confession. I never fully removed that cap. It was loose but didn't want to drop; I couldn't figure out what else was holding it in place. By then I know the pump was sloppy and that all other bearings were near perfect. Figuring I'd let it as is to avoid causing problems, I just retorqued it and quit. So what did I do?

Does someone have pictures or at least a better description of how this all goes together? Not knowing what I did I'm not sure how to correct it. It's certainly useable, but it didn't leak a drop before.
 
Here's a pic of the rear seal which has bolts attached from the maincap to the seal. The maincap has ope seals along the sides.
 
Where is it?
a106250.jpg
 
Try this
http://www.ytmag.com/cgi-bin/viewit.cgi?bd=ferg&th=62676

Search this site for packing and 222 hits come up.
If it were mine I would plastigauge the bearings to know better what you have for clearance.
 
Thanks for all your time. The pictures help a lot. When reading the archives I missed those great pictures. I guess I was searching for the wrong words.

Plastigauge results: connecting rod bearings all between .0015 and.0025 and other main bearings a hair under .003. But note I did not plastigauge the rear main since I didn't take the cap off.

Should that cap come off easily after removing the cap screws to the rear oil seal and then the bearing cap screws? When it didn't come off easily I figured I'd skip it to avoid damaging anything. But apparently I'd already messed up the seal and now it needs to come off. What's the appropriate method?
 
Rear main cap does not come off real easy because of friction from the packed in string on the sides of the cap. I assume you have the 2 small bolts removed form the main cap that holds the rear main oil seal. I wiggle the cap loose by squeezing the two main caps bolts together.
I have seen the rear main worn and front 2 mains ok. I assume this is due to out of balance clutch flywheel assembly. .003 is a little more clearance than I would prefer. .001 ,.002 is what I strive for. It has been a long time since I did my TO20 and hope I have not forgot anything.
 
Duner-- Thank you for the excellent help. It sounds like I really ought to pull that cap both to redo the packing and to check the clearance. It also sounds like maybe the main bearings should be on my project list at some point. That said, while I'm obviously new to this type of work, when I had the oil pump apart it measured out of spec to my reading of the manual. I've hoped that after rebuilding it the oil pressure may be enough better to serve me for some years yet given I don't work the tractor terribly hard.
 

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Back
Top