D7 17A with Stuck Engine

I have a 1956 D7 with a stuck engine. It hasnt been started in about 6 years. Initially I thought the starter was bad because it smoked when I tried to turn the engine over. I had the starter rebuilt and purchased new batteries. That didnt solve the problem. The ground terminal on the battery melted when trying to start the dozer with the rebuilt starter and new batteries.

I thought about removing the radiator and hydraulic fluid tank to gain access to the crankshaft pulley so that I could manually rotate the crank using a large socket wrench and pipe for leverage. Instead I used a tool that I made using a starter mounting flange, a pinion gear, and a shaft with a welded nut. I then used a breaker bar, socket, and pipe for added leverage to turn the nut, pinion gear and flywheel. When I wasnt able to turn the flywheel using the breaker bar, that confirmed that the engine was stuck.

I removed the injectors and valve covers. I didnt see any rust or water. There was a thin coating of oil on the components under the valve covers. I then sprayed PBBlast into each cylinder. After unsuccessfully trying to manually rotate the flywheel I then added a cup or more of Lucas Oil treatment diluted with mineral oil to each cylinder and let that sit for two days. I tried again to manually rotate the flywheel but to no avail. I made sure the clutch was disengaged and the transmission in neutral.

After unsuccessfully moving the flywheel with a breaker bar I then resorted to using a come along and pipe for leverage and ended up breaking the end of the breaker bar. I then used a large adjustable wrench, a pipe for leverage and the come along, and left things in tension. I plan on getting back to the dozer in a couple of days.

The large adjustable wrench is all I had left in my arsenal of tools after breaking the breaker bar. I can see that the adjustable wrench doesnt have a firm grip on the nut. Anymore cranking on the come along may end up stripping the nut. Im thinking about making another tool by welding a 1-1/8 12 pt wrench directly to the leverage pipe.

A question I have is can I access the underside of the piston and cylinder by removing one of the side plates? If so I could I then spray lubricant into that area?

Any help, insights and responses greatly appreciated!







This post was edited by PinionGear on 08/18/2021 at 05:49 pm.

Myself I would fill the cylinders with ATF
and set up a bar like you had on the
flywheel with a come a long on it set pretty
tight and let it sit for a few days to see
if that helps

I was given a Case 930 with a stuck engine. I filled the cylinders with 1/2 and 1/2 atf and acetone. Took a month of soaking and bumping the wrench on the crankshaft every day when I would get home from work. Once it moved a little, I started working it back and forth till I made a few full rounds. Hooked the started up and she fired up. Blew all kinds of crap out the exhaust for a long time. I ran that engine for 10 years afterward. One of the cylinder liners let go at the bottom and filled the crankcase with water overnight. I could fix it, but I don't want to put the money into it now.