Upgraded to the (up to) 1993 G30 booster, found a NOS one for less than the crappy new remans. To do this isn't exactly straightforward, but I did learn a new skill int the process, bending and flaring brake lines. I used Copper Nickel line, it flares and bends easy.
To use this you need to cut the booster pushrod shorter, I had a buddy of mine TIG weld it to the shaft on the new one. Stock is about 3.5% from the booster base to the center of the eye. The holes in the booster bracket need hogged out to fit the 10mm studs on the booster, and the lower pair of holes need slotted a bit. Then the lines from the proportioning valve to the booster need custom bent since the ports are switched over the original. (the matching prop valve still uses SAE brake line fittings so you can reuse your old ones)
I still need to get the brakes fully bled, I have an pneumatic "power bleeder" but it is pouring today so I still haven't gotten to test it.
New booster is bigger (I think 11") and is a dual diaphragm.
