Hello all, got an old 79 kw w900. Simple tractor converted to dump truck. Ive been in the process of fitting a drop underneath. So thats taken moving quite a bit, secondary air tank included. Ive relocated secondary to between fuel tanks and been replumbing.
Ive got service brakes back and working, but having trouble with parking brake. As of last weekend my PP valve had no pressure to it, realised I forgot a supply line to an R8 valve. This weekend hooked the supply to the R8, now my yellow and red knobs have pressure but just push back out. Even held in for 20 seconds no brakes releasing, the knobs just push back out. No audible air leaks from either. The trucks sat for maybe two months with fresh drums and shoes, I dont believe theyve rusted together. Its cold but not frozen brakes cold. Im sure I goofed some line up somewhere.
Still learning old trucks myself but this truck does have a blue brake knob as well. It has no pressure to it and moves in/out without resistance. Starting to think its plumbing might be whats sticking me?
Got diagrams printed for my valves, been doing research but im pretty stuck. Ive copied the plumbing as well as I could to how it was, no issues before my overhaul. Will attach pictures of valves and explanations to where/what its plumbed to.
First picture: My SR1 valve has a line from reservoir port to primary tank (I redid this one). Delivery port jumps to service port on an R8 valve (existing). Supply port heads up the frame rail and I lose it behind the cab (existing).
Second picture: The R8 I havent touched anything except the supply line which was plumbed to the secondary tank. So I replaced that and ran it to primary tank. Everything else existing. Problems kinda started and went weird after running this line. As said before no pressure to brake knobs prior to hooking that supply line back.
Thanks for any suggestions and help in advance. Have a great rest of the weekend.
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