620 main bearing removal

farmerjim72 · Dec 28, 2020

Got my dads 620 running the other day and quit after about 6 minutes of running it locked up tight come to find out it’s locked in the bearing behind the flywheel. We have it pulled apart to the point of the block and rods pistons are out and the fly wheel off just trying to see how you get the bearing and housing out of the end or do you have to pull the whole crank out first and the drive the housing out. Did a 730 diesel a few years ago and were able to just replace the bearing on the ends without pulling the crank. Any help would be great. FYI it sat for 25 years after the cows left do to a radiator leak and we fixed that part.

MSD · Dec 29, 2020

You have to get the bearing housing out first. Crank won't come out without the bearing housing removed. Hopefully the bearing isn't seized to the crank. That might make it tougher to get out. Why did it lock up? Always look at the oil pressure after starting to make sure you have some.

farmerjim72 · Dec 29, 2020

Thank you I’m assuming the bearing is stuck on the crank. And when we had it running the oil pressure was on the high side was gonna look at the line to the bearing when we got it apart. The rockers had oil the connecting rods had oil so not sure why this one locked up but it looks dry

Mike M · Dec 29, 2020

Those 20 & 30 series 2 cyl. models seem to have an issue with the rubber packing that seals the oil pressure to the bearing housings swelling closed and stopping oil flow. In the past others have posted pictures of a simple fix to help prevent this in the future. It involves screwing a electric lamp nipple into the hole to support the packing.
Depending on how bad it is stuck you might have a hard time getting the bearing housing off. IIRC Those aluminum bearings have a dowel pin driven in from the side to help keep them from spinning in the housing that would need removed before the bearing will come out.

JIM MN · Dec 30, 2020

What Mike M said, rubber packings?? Get both left and right main bearing housings off.. Do bearing and crank repair; but do put in new oil passage way seals between the main case and main bearing.. Part number A4847R called gasket, but are a small square rubber packing.. What happens to packings, is they flatten out with age, get hard and block off center hole carrying oil to main bearing.. New packings with Mikes fix would be good. Also, do check your oil lines inside the crankcase-- any cracks or loose fittings??

PJH · Dec 30, 2020

Everything Mike said.

Here's some pictures from the right side of my 630. There used to be a guy on this site who called himself Bushhog Papa. I haven't seen anything from him in a very long time. He was the first that I saw mention this idea, but others may have mentioned it before him.

The hole in the case is threaded. This picture shows a piece of tubing in the hole. I'm holding another piece of tubing to show how it looks, with a temporary nut to help get it screwed in.

In the parts book, the black piece is called a gasket. Part number A4847R. The tubing obviously has to be screwed into the case far enough to let the main bearing housing tighten up properly.

Mike M · Dec 30, 2020

I had hoped you would show up with those great pictures showing what is going on !

NoDakInMN · Dec 30, 2020

(quoted from post at 11:28:06 12/30/20) Everything Mike said.

Here's some pictures from the right side of my 630. There used to be a guy on this site who called himself Bushhog Papa. I haven't seen anything from him in a very long time. He was the first that I saw mention this idea, but others may have mentioned it.

Hope he is alright, he helped me out more than once.

PJH · Dec 30, 2020

"Hope he is alright"

Yes, I hope he is too. He and Mike and Tim and Jim (Fixerupper) are good people and have helped many of us many times. I also wonder about Bob. He's been missing for many months.

fixerupper · Dec 30, 2020

This post reminds me to mention the bushing idea to my neighbor who has the crank out of his 620.

farmerjim72 · Dec 30, 2020

I would just like to thank every one with the post about the seal. The seals was sealed shut and when I pulled it out the oil came running out . Going out tomarrow to find somthing to Put in place in the hole. Pulling the other side apart tomarrow and lucky part was the crank looks great yet

620 John · Jan 1, 2021

(quoted from post at 20:35:11 12/30/20) I would just like to thank every one with the post about the seal. The seals was sealed shut and when I pulled it out the oil came running out . Going out tomarrow to find somthing to Put in place in the hole. Pulling the other side apart tomarrow and lucky part was the crank looks great yet

That's kina scary. My brother's 620 has high oil pressure. I read about this issue a while ago so this summer I took the crankcase cover off and the oil lines feeding the main bearings. Couldn't see anything but I stuck a small pick inside the oil passage and could feel the rubber sealing washer had swelled up in both main bearing passages. I took a drill bit and turned it by hand to try and clear up the passages. Got the oil pressure to drop that time. But then latter this summer he said the oil pressure went back up again. I'm guessing we still have some debris clogging up the passages

620 main bearing removal

farmerjim72

Member

MSD

Well-known Member

farmerjim72

Member

Mike M

Well-known Member

JIM MN

Member

PJH

Well-known Member

Mike M

Well-known Member

NoDakInMN

Member

PJH

Well-known Member

fixerupper

Well-known Member

farmerjim72

Member

620 John

Member

Similar threads