u/Xxytm200xX

Hey there all. Picked up my first diesel ever recently. Its an 89 12v with a VE pump in a 1976 D300. After buying the truck I noticed a pretty good leak coming from the pump so after some investigating I found the culprit. The rear block seal is bad and is leaking in between the pump housing and the block. That being said, Im curious if I can replace just that seal with the pump still in the truck. I know the top of the pump will need to come apart but is it worth it to try and do it in the truck or should I pull the whole pump? Let me know. Like I said first ever diesel so very green when it comes to something with no sparkplugs. Thank you in advance!