In the process of freeing a stuck Injector pump assembly (4F6921) for a 9U D6 (D318 Motor), I broke one of the plungers. There are several aftermarket maker of plungers and barrels on the market but none say what pump assembly they fit. Anyone have the part numbers for the plungers and barrels for 4F6921, or 5M9758 pump assembly? or even a good pump assembly they might want to part with. Thanks bboaz

Here is a link to 3 used ones I believe...…………..

www.ebay.com/itm/3-CATERPILLAR-FUEL-INJE...f:g:2fsAAOSwhgxeZ9Ld

Have a good day...….Bill

Cysco, Two are 7mm for the D311, and one is 8MM for the D315 and D318. Made an offer. Thanks bboaz

I got the three pumps off E-Bay, and the 4F6921 pump was as worn out as the ones I have. Still looking for part numbers for the barrels and plungers for the 4F6921 pumps.

Rebuilt the transfer pump for this machine. Surfaced the pump body and bottom plate to remove the rust where the gears run to reduce clearance, replaced the rusted gears with new gears from Caterpillar and re-tamped the seals in the pump where fuel was bypassing around the shaft. If I can find new plungers and barrels for the injection pump this fuel system should be in good shape.

I wouldn't bother looking for obscure barrels and plungers. Just get the latest new pump assembly
8M9758

"bboaz" wrote:

Cysco, Two are 7mm for the D311, and one is 8MM for the D315 and D318. Made an offer. Thanks bboaz

I have a 1957, D315 in a 955C Traxcavator with two 4F6921 Pump Assemblies and two different Pump Assemblies.

The two different pumps aren't Cat yellow and don't have the needle bleeder 2A389, also they have a flatter top with a smaller radius chamfer - I don't see any part No. and don't know the size till tomorrow. Are you needing the 7mm or 8mm?

Yea the new ones don't have the bleeder screws, the part number will be on the flange side of the pump, cant see it when mounted on inj. pump housing.

I have 7 small pumps 4f6921

"Rome wrote:

Yea the new ones don't have the bleeder screws, the part number will be on the flange side of the pump, cant see it when mounted on inj. pump housing.

Thanks for the info

gemdozer, sent you a private message about 4f6921