Good evening, I have replaced my entire front and rear including a new master cylinder on my 73 challenger rally brake system and ran into a snag. With my master cylinder bench bled and primary and secondary reservoir full I am unable to get any fluid to the back brakes, so I removed the fitting at the master cylinder for the rear and no fluid runs out but does run out for the front brakes so I have no gravity flow to the rear. I can make fluid run out of rear brake port if I use my syringe on outlet port in reservoir but no free flow like the primary. I always thought both primary and secondary have gravity flow so am I missing something any input would be appreciated
Brake issue
- Thread starter HYDRO
- Start date
Xcudame
Well-Known Member
Sounds like something wrong with the "new" master cylinder. It happens! with the rubber bleed hoses connected to both front and rear ports, you should be able to flow fluid all day long!
Side note, replacing every thing new, you did capitalize on the opportunity to use DOT 5 brake fluid, right?
Side note, replacing every thing new, you did capitalize on the opportunity to use DOT 5 brake fluid, right?
Steve340
Well-Known Member
Probably not "gravity flow". The front has no residual pressure valve but the rear drums should have one.
The residual valve will hold the fluid in the reservoir.
The residual valve will hold the fluid in the reservoir.
So I should pump petal,hold and bleed the good old fashion way, was trying the vacuum method with no results to the rear
Chryco Psycho
Well-Known Member
The residual pressure valve should allow free flow out of the master but limits the return into the master .
Steve340
Well-Known Member
If you could bench bleed both the front and back parts of the master cylinder it is pumping OK.
Does it have a booster and did you check the pushrod adjustment?
Does it have a booster and did you check the pushrod adjustment?
Hey Steve going to remove master cylinder and bench bleed again using syringe and check the pushrod travel on my booster because I did disassemble booster cleaned and reassembled and thanks for your input
Challenger RTA
Well-Known Member
Did you reset you proportioning valve? Show a picture of it.
Last edited:
Xcudame
Well-Known Member
You can bleed the master cylinder with it on the car! No need to remove it! Challenger RTA may be onto something!
Steve340
Well-Known Member
I vacuum bleed these days - it works well on 99% of cars. No risk of upsetting the brake valves and no need to bench bleed.
Does the master push fluid out if you push the piston in?
If not it might be faulty.
Does the master push fluid out if you push the piston in?
If not it might be faulty.
moparleo
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All steel lines, 3 rubber lines replaced ? If so it is also good to blow the lines out with air before you close them up. Smetimes all it takes is a little spec of pspacking, tape etc.. to get inside a new line when the ends are open before you install them.
Fluid from a new, sealed bottle as well.
Also make sure that you use a new master cylinder, never a rebuilt. Everything else is ok to use new/rebuilt but the M/C is the heart of the brake system and must be reliable.
Vacuum bleeding is what we always used at the shop. One man and no problems damaging anything in the system.
Fluid from a new, sealed bottle as well.
Also make sure that you use a new master cylinder, never a rebuilt. Everything else is ok to use new/rebuilt but the M/C is the heart of the brake system and must be reliable.
Vacuum bleeding is what we always used at the shop. One man and no problems damaging anything in the system.
