This is the third failure ive had with my brake line tuck. After it is all said and done, my rear brakes still wont grab. I have a summit adjustable proportioning valve and all my brake lines are new stainless steel. What have i done wrong or what am i missing? If the valve is all the way increased, shouldnt that run max pressure to the rear? Any help would be amazing.
maybe the lines arent connected to it right…my guess dont use that prop valve and try your stock
one …see what that does…then if it aint that then maybe you flared the ends wrong…maybe they got crushed or some thing…try checking all that…and i will be on the watchout for your updates on this thread…
Your problem is likely your proportioning valve or your chosen routing arrangement.
The front portion of your master cylinder goes to where? And the rear portion of your master cylinder goes to where?
An adjustable proportion valve only has the ability to reduce the pressure to a specific area of your brake system.
An adjustable proportioning valve will not increase the pressure to the rear if there is not enough pressure coming from the master cylinder to begin with.
the two inputs from the m/c are going into the inputs of the prop. valve. it doesnt matter which one goes where, both are the same pressure. (correct me if i am wrong). then the front left and front right connect into the front outputs. and there is one rear output i had to run a single rear line and “t” it to the rears. all my flares are good, and nothing is kinked. i bled my brakes and there is no air in the system. when i apply the brakes, the fronts grabb(ish) but the rear doesnt. you can turn the rear wheels with the brakes applied. any advice?
oh, maybe a residual valve?
Hello,
You wrote “the two inputs from the m/c are going into the inputs of the prop. valve. it doesnt matter which one goes where, both are the same pressure.”
No, the output volume of each master cylinder section could reach the same volume and pressure could eventually build to the same level however you have changed the fluid volume requirement to build pressure. The calliper pistons sizes are diffrent front to rear.
As you are likely aware the brake system in our cars is initially set up as a diagonal split system, one front brake connected to one rear brake calliper forming a pair.
Our master cylinder is split in to two sections, primary and secondary each portion of the master cylinders was specified to deliver enough fluid volume to produce pressure in one front and one rear calliper pair.
Connecting the two front callipers and two rear callipers together has now re arranged the output volume requirement for each paired portion of the master cylinder. The front callipers having lager pistons requiring a larger volume of brake fluid then the rear.
First guess without working on the system is that you are likely building so much pressure in the primary portion of the master cylinder that the secondary section of the master cylinder is not even being compressed or activated.
With the way you have your system setup at present you could open the calliper bleed screws on the front callipers and compress the pedal thus allowing pressure to escape from the front portion of the system. From there now determine if the rear callipers are activating/building pressure.
You might also measure the output volume of the front/rear split system as you have it setup and from there determine why you are unable to produce pressure in the rear portion of your system.
now this was alot of help here ppl. thank you for your post. i did not know all of this. let me try and do a few diff things according to your post. i will post back as soon as i try these things and let you all know what happens. and again, thank you for your reply, your awesome:rockon:
Let me know if you need any more help. Here is what my Integra setup looks like, rather than use a proportioning valve I went to seperate dual masters with an adjustable bias bar.
Wow…i just fell in love with someone’s brakes…ah…uh…ohhh…wow. Now that is the most beautiful thing i think i have ever seen…seriously…where did you get that setup? That is freakin amazing!