JD 720 diesel in crankcase

NorthMNJD4020 · Jun 9, 2023

Anybody have the seal part numbers for the transfer pump on a 720 diesel? (I need to get a book) Noticed she's starting to fill up with fuel yesterday and would like to start here as others seem to suggest. Other recommendations on things to look for would be great too.
Thanks in advance.

MSD · Jun 9, 2023

AR-395 R is the Deere seal number.

NorthMNJD4020 · Jun 9, 2023

(quoted from post at 10:15:24 06/09/23) AR-395 R is the Deere seal number.

Do these come with the felt washer too or is that a separate part number?

wore out · Jun 9, 2023

(quoted from post at 07:24:34 06/09/23)

(quoted from post at 10:15:24 06/09/23) AR-395 R is the Deere seal number.

Click to expand...

Do these come with the felt washer too or is that a separate part number?

Felt washer is R20139.

2 seals are required and come in a package of two but are sold individually. The number the John Deere parts system likes to see is AR395R with no space or hyphen.

You can view the parts catalog at https://partscatalog.deere.comjdrc/search

ET · Jun 9, 2023

Isn't there a vent hole in the bottom of
the fuel pump drive cavity that allows any
fuel that gets by the seals to dip out on
top of the engine?
The fuel leak I've found most comon is
the little stand pipe under the fuel rack.
It has an o-ring on each end of it that
gets hard and leak.

buickanddeere · Jun 9, 2023

If the leak is from the transfer pump . Do not be surprised if the shafts are worn rough and require replacement .

Dieseltech · Jun 9, 2023

That O ring tube is the lube oil supply for the injection pump tappets, not fuel. It's also common on high hour injection pumps that the delivery valve gaskets are eroded inside, then fuel will leak past into crankcase oil.

Scott 730 · Jun 9, 2023

I just finished re sealing the transfer pump on my 730. The shaft had a nasty groove where the fuel side seal rides. The oil side was fine. Since the fuel seal goes down in the casting first, I placed 2 fender washers in the bore, and then installed the first seal. Plenty of room left for the felt washer. Works beautifully, as the seal is now riding on a new section of shaft.

I "think" adding the weep hole was a running production change. Not 100% sure, but thought I had read that somewhere.

This post was edited by Scott 730 on 06/09/2023 at 01:11 pm.

rrlund · Jun 9, 2023

My 730 did that. It was the drip tubes on the injectors.

Dieseltech · Jun 9, 2023

I'd suspect worn injector valves before the tubes, unless they were left loose. Those injector return tubes don't even go back to the fuel tank like other engines do. They go to the head INTAKE air port, and good valves pass very little return fuel for lube/cooling anyway. Worn/eroded delivery valve gaskets are common leaks, next could be severely worn plungers/barrels.

old popper · Jun 10, 2023

CR 5153, or National 471472 are the numbers for the seals on my '57 720 D.

JD 720 diesel in crankcase

NorthMNJD4020

Member

MSD

Well-known Member

NorthMNJD4020

Member

wore out

Well-known Member

ET

Well-known Member

buickanddeere

Well-known Member

Dieseltech

Well-known Member

Scott 730

Well-known Member

rrlund

Well-known Member

Dieseltech

Well-known Member

old popper

Well-known Member

Similar threads