Originally Posted by vinniekq2
if the pedal pumps up the the adjustment is too low.Your brakes need to be square on the backing plate.The bottoms need to be adjusted to just touching.The tops when resting on the stops need to be close to adjusted.The pins need to be long enough that the wheel cylinder does not run out of stroke.The extra 2 wheel cylinders will need a longer stroke master to move enough volume of fluid. The boost does not make a difference to the volume of fluid moved. You might consider using wheel cylinders with a reduced bore to get more movement for the shoes.
If you cannot find smaller bore wheel cylinders,have a machinist sleeve the cylinders.
Th truck only has 23,000 miles on it, ex fire water tanker truck, I saw zero wear on the backing plates if thats what you mean, if you mean the back brakes need to be re-adjusted than I can do that.
Longer stroke master with this power brake booster is not going to happen I do not think, I have looked thru catalogs at Napa, on-line ect quite a bit, 1 1/4 bore master was the largest I could find to fit this brake booster but unfortunately stroke is not always listed and its tough to get anyone to answer that question.
I really do not want to get into sleeving wheel cylinders if possible, I just got this all together and dont relish the though of pulling out the axles again and replacing the gaskets ect.
Maybe you know of an aftermarket master cylinder brake booster assy that would work? I can replace these easy enough if need be