Diesel Brake Boosters-2 series

[dpsam]

Good morning. Haven't been on the forum in a long time, as our D24 is a memory, but I need some help, if someone will be so kind.

Recently I did an engine swap that required the use of the "pancake" booster. This is a gold-colored unit, identical to the 740 booster, but with the rear bolt pattern to fit the 240's firewall. It is a diesel booster. Apparently it's bad. The rod is free to rotate and I am getting no boost despite good vacuum. My problem is replacing it. I can have it rebuilt, but questions have arisen as to whether this is an OEM unit or not. One builder says he has a unit on the shelf but that it is NOT just like mine. 10" diameter, but about an inch or so "thicker" from firewall to M.C. mounting surface. He says it is OEM. Doesn't have the same tapered shape either.

Our diesel did not even have the pancake, but was an '85. Some posts I've found say the thin, single diaphragm unit was only used before the vacuum pump was installed. I sure don't know. Can anyone shed any light? Anyone know of a source? I want to replace this one, then have it rebuilt and put it on the shelf for the next swap.

Thank you,
Dave