Hey Rainman, so I explored the parts route for the original booster. There were several showstoppers for me. For one thing, there is no more Toyota kit out there that I can look at to determine what exactly needs replacing. I can potentially take apart an old booster, but to replicate the individual components would be neither practical nor economically feasible for me.
One project I have on the back burner is to fully pilot the dual diaphragm booster in the pics below. The dimensions are perfect and the spec is right on. The way my supplier partner explained to me is that there are two types of 44610-60050 booster. The U.S. market got the Tandem version, and there is this Aisin version, also designed for FJ40s.
I ran it in my car for a couple of weeks. It worked fine, but it is a bit thinner than the Tandem Booster. Therefore, my proportioning valve bracket was left dangling; I couldn't pull it sufficiently forward due to the hard brake lines. It could just require pulling harder on the lines, since I've seen
other folks install thin boosters and still hook up the bracket successfully. Worst case, the issue can be resolved by creating a different bracket.
The thinner dimension of this booster does offer some nice advantages. It is easier to install and leaves extra room in that crowded part of the engine compartment, providing better access to the carb, manifold, and EGR stuff, etc.
This project got side tracked when PartsGeek sent me a replacement for the broken Centric booster they sold me. I put the Centric booster back on to make sure it works, and then other things took priority.
I intend to pick up this project again later. One of the things I hope to do is to pilot this booster in someone else's truck so I can get user feedback, which is something I did with the
single diaphragm booster (4610-60030) that I will be making available later this week.
