D4 7u sump cracking…

Hi there, I am rebuilding a D315 and have the choice of two sumps to use , an used apparently uncracked one and a well bronze welded one with a good layer both inside and out, I have had to weld two others in my time with D4,s and wonder if it is only a matter of time till they all crack and if so will i be better installing the already repaired one . Is it a wise idea to install a little rubberised canvas padding between the transverse spring and the sump to prevent some of the impact/ wear? Thoughts please

My own opinion says to use the uncracked one, but be sure it matches the repaired pan. The guys that know, should chime in; I believe there are two versions of that sump, not interchangable due to a balancer?

Interesting that you repaired yours. I had one that when a light used, you could see thru it. Very worn/thin. With all of the nooks and crannies I can't picture repairing one without a lot of time consumned. I would guess the bottom side almost needs machining to make it nice and level, but that's when the rubberized canvas could help things a lot.

I have always wondered if it was possible to powder weld/spray arc repair one. Several mechanics here have always recommended using a good replacement. Do you have any photos of the repaired one? Thx. JM

I wonder if laying down a layer of bronze on the uncracked pan to provide a buffer as well as the canvas would make it bullet-proof. The design obviously isn't up to the task and that might be because the pan isn't thick enough or of the right material type.

Hi JM , the one I repaired 25 years ago i cut out the cracked section and welded in a section of doner cast from a surplus gearbox in place with cast iron rods, preheated the sump to red hot then cleaned up with sandblaster, welded short beads and peaned with needle gun while cooling, shallacked the inside and its been in a hard worked dozer ever since. I will get a pic of the one that is bronze welded I currently have, not my weld job, I suspect the cracking happens when the transverse spring is allowed to get loose and hammering/shock loads occur as the engine block lifts off the spring under torque. The one I bronzed was a customer and he drove it away and ive never heard of it again so i assume the weld held, similar process with serious preheat before bronze but no added patch.