ok so iam not getting any brake fluid to rear brakes at all lines are all good new shoes rubber line from frame to lines in rear cylinders all that jazz i have fluid comin from master down to proportioning valve but seems my mecahnic of 23 years and myself cannot figure out why my 1989 s10 blazer 4x4 5 speed 2.3 tbi has 2 yes i say 2 of these valves ?????? yes i said two i have the one that sits directly under mc with dummy switch on then there another one that sits directly behind that one line runs from front valve to this 2nd one then back to rear brakes i have never ever seen one like this and neither has my mechanic.... and we have pretty much narrowed the fluid problem down to it cause we took all lines off and pressed brakes got fluid through all lines from mc but when we took the line that goes from this 2nd valve off that runs back to rear brakes we got nothing coming through this line at all..... sooo can anybody tell me what exactly this second valve persay is ??? and is it actualy a proportioning valve???? mystery to me and to my very seasoned mechanic who has owned 9 blazers in his time and has never seen this before.... HELP I HAVE NO REAR BRAKES thanks william and if a picture will help let me know i would be glad to share this with anybody..................

 

Sounds like its rigged up for some stupid reason, maybe someone had to join 2 lines or some crap. I would buy the equipment to make it stock or better.

 

you sure that second one isnt for some kinda ABS set up? my 1990 fullsize had that thing and was causing my pedal to go really low to the floor. i just bypassed it

 

Any way you can get us a photo? There is a proportioning valve, and a metering valve. The proportioning valve does just that - front rear split, and the metering valve applies rear brakes a split second before the fronts and releases them a split second after to prevent fishtailing, and it also holds a little residual pressure to keep the shoes dragging to assist in auto adjusting. Neither of these valve bodies have wire plugs (Im 90% sure). The ABS module has wire plugs and all 4 lines (or just the rears) going into it immediatley after the MC