Is there a common cause for no rear brakes and brake light on?

[Myasylum]

This is for a 72 Satellite.
Front brakes work great, but no rear brakes and the brake light is on, in the dash.
Is there a common cause for this?
Reservoir in the master cylinder is full, I tried to bleed them and nothing.
Hoping this is something simple, but it never is.
Thanks!

 

[Kern Dog]

Common cause?
Maybe....Either you have a leak somewhere in the rear circuit, air in the system, the proportioning valve is stuck, blocking fluid flow to the rear brakes or a few other things.

 

[Myasylum]

Where do I start? There doesn't seem to me a leak that I can see.
Can I clean out a proportioning valve, or do I have to buy a new one?

 

[Kern Dog]

What usually makes the proportioning valve BRAKE light come on is the shuttle inside moves out of the middle range where it usually stays. It then goes all to one side. The edge of the shuttle hits the sending unit. See pictures:

This was a picture of a 4 wheel drum distribution block but the function of the BRAKE warning lamp is the same. If that light is stuck on, maybe you can tap on the valve with a small hammer to see if the shuttle moves. Maybe tap it as someone presses the brake pedal.

 

[Myasylum]

Prefect! Thank you!

 

[RemCharger]

I think they bring up brake warning light in the owners manual as well. If the car came with one.

 

[Myasylum]

It didn't come with much, lol. One problem at a time.

 

[Rishi]

If the brake light is on, after starting with no brake applied, I vote proportioning valve. But if it only comes on while applying the brakes, I vote a master cylinder issue.

 

[Myasylum]

I will start with the proportioning valve. I'll just get a new one.
The light is on all the time.

 

[dadsbee]

You sure that the light is not on because the parking brake hasn't fully returned to press in the switch?

 

[Don Frelier]

You sure that the light is not on because the parking brake hasn't fully returned to press in the switch?

Sounds like he's not getting any fluid out the rear either.

 

[WileE]

I will start with the proportioning valve. I'll just get a new one.
The light is on all the time.

Whoa... don't be so quick to buy a new one. If it's chinesium, it may be worse than what you have. Take it out, apart, clean it. It may be that simple.

 

[Beekeeper]

Whoa... don't be so quick to buy a new one. If it's chinesium, it may be worse than what you have. Take it out, apart, clean it. It may be that simple.

Follow this advice you’re not gonna be happy with the Chinese ones. I would go in depths and post pics and all but just trust us. Use these guys for your rebuild kit
Mopar Parts | Muscle Car Research LLC

 

[Myasylum]

First time I looked at it. Not real pretty.
What rebuild kit do I get??

 

[dadsbee]

Did you take the wire off the valve switch? If not, based on that pic, your light shouldn't be on...

 

[eldubb440]

First time I looked at it. Not real pretty.

they're all pink on the inside.....err something

 

[RemCharger]

they're all pink on the inside.....err something

I thought it was, flip them over and they all look the same.
Unless uncle Beryl was wrong.

 

[RemCharger]

Did you take the wire off the valve switch? If not, based on that pic, your light shouldn't be on...

Agreed. The wire isn't on

 

[blue69runner]

They are all pink on the inside !!!!!!!! Would take it apart and clean every thing with WD Forty. Small soft brisel brush but not wire brush run through the body. Maybe some small trash in there. If not just might be in the master cylinder as stated.

 

[Myasylum]

I took the wire off. Don't need a red light in my face as I drive. I already know somethings wrong.