Hello everyone. I completely rebuilt my rear brakes and was attempting to bleed them today. When we opened the bleeder and started to press the brake, it seemed like the brake was a little tough to press and after trying for a while, we got no fluid to come out. The master cylinder was full and wouldn't go down in fluid level. So I'm assuming the brake lines that exit the master cylinder or the lines underneath the car are clogged. None of that has been replaced, only the rear brake assembly and the lines that come out of the "T." I should've known it was going to need to get replaced so I started to tear things down. Underneath the master cylinder, bolted to the inner fender, I see this piece. What is this? Also, not quite sure how to remove it. It seems like the bottom of it has one massive rivet or something like that but I doubt that's how to get it off. Any help would be appreciated, thanks guys!
What is this?
- Thread starter 340 RR
- Start date
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junkyardhero
Well-Known Member
that's your porportioning valve/metering block with the safety switch.
judging by the condition, it's probably trash inside.
they're generally bolted to the frame or lower apron.
it would help tremendously if you told us what car you're working on as well.
judging by the condition, it's probably trash inside.
they're generally bolted to the frame or lower apron.
it would help tremendously if you told us what car you're working on as well.
Professor Fate
Push the button, Max...
That's your proportioning valve, and it ain't a Mopar unit. Probably Ford.
Commonly used in aftermarket "fitzall" power brake kits, usually paired with a Ford or GM master cylinder and generic booster.
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Sorry about that, don't know how I didn't include it. 1973 roadrunner with a 340. I'll try to get it off tomorrow and order a replacement mopar unit. I'm dreading going under the car to change the brake line but I'm sure that's gotta get replaced too.
They can be pretty pricy
What ever you do, don’t get stainless lines, they are hard to bend and seal.
Summit racing has some decent stuff.
I used NiCopp for the lines in the rear that go to each brake assembly. I assume that would be good to use up front too, right? Thanks for the advice
If you find a used one, they make rebuild kits for them. Don’t buy new they’re known to leak.
Cars with front disc brakes use a proportioning valve. 4 wheel drum cars used a distribution block. They are not the same thing.
Distribution blocks look like this:
Proportioning valves look like this:
The proportioning valve for disc/drum systems has a few functions.
It is designed to reduce pressure to the rear brakes since the rear brakes don't need the same amount of pressure as the front needs.
Disc calipers need more volume and pressure than the wheel cylinders in the rear drum brakes.
Distribution blocks look like this:
Proportioning valves look like this:
The proportioning valve for disc/drum systems has a few functions.
It is designed to reduce pressure to the rear brakes since the rear brakes don't need the same amount of pressure as the front needs.
Disc calipers need more volume and pressure than the wheel cylinders in the rear drum brakes.
junkyardhero
Well-Known Member
not to say that ford stuff doesn't work, but given the state of affairs i wouldn't even bother attempting to rebuild it. besides the fact that it's off of an unknown application so who knows what the porportioning is on that.
you'd be much better off with something like this:
you'd be much better off with something like this:
Disc Proportioning Brake Valve & Metering Valve For Disc Drum A, B, C, E body | eBay
For A,B,C and E Bodies from 1960-1974 with disc front & drum rear. If this is the case you will need to tap the stud out of the bracket that is included on the valve. If you don't have the stud on the car you can use the one provided on the valve bracket.
www.ebay.com
Professor Fate
Push the button, Max...
Also depends on what the rest of the system is composed of- so many aftermarket conversion kits use Ford or Chevy master cylinders (or Wilwood) that it's hard to believe that any factory prop valve would have correct proportioning built in.
"Mopar" kit with Chevy master:
"Mopar" kit with Ford master:
Not that these kits can't be made to work, but it can take a bit of finagling to do it. If this is what the OP is dealing with, best bet would be to plumb the front brake circuit directly into the rear master reservoir, and the front reservoir directly into an adjustable prop valve to the rear brakes; and skip any sort of factory prop valve.
A Mopar prop valve is best used in conjunction with a Mopar Master and brakes, and if that's not what you have then just go with an adjustable unit. It would probably be cheaper than a repro Mopar unit, too.
A picture of the OP's system would help a lot.
I attached some pictures showing more of the brake system. I already started taking some of it apart. The car has drums on all 4 corners so I assume that means that that piece is a distribution block, not proportioning valve. According to the "Mopar Kit with Ford Master Cylinder" picture Professor Fate posted, it seems like this car has a ford master cylinder. Which would make sense because Fate also said that the distribution block looks like one from a ford. Looks like the brake booster is oem mopar. Should I look into changing both the master cylinder and the distribution block back to mopar? Is there a different direction I should go with this? Thanks everyone!
Professor Fate
Push the button, Max...
Hmm... strange. that's a Mopar master (4 bolts, GM & Ford are 2 bolt), but it's a disc brake master, not that it matters too much. Just no residual valve in the port for the front brakes, but it's not absolutely necessary. I's be more concerned with how the (Ford?) proportioning valve was plumbed- if incorrect, that could have a whole bunch to do with why you're not getting any fluid into the lines and to the bleeders.
Do you think the best course of action would be to find an oem used mopar distribution block instead of trying to fix the ford one already on the car? I've never ripped into one so I'd have to learn how to plumb it. I have someone that's willing to sell a good used oem mopar distribution block for $75. I might just go with that. Should I keep that master or go with something else? Never dealt with this stuff so I don't know what setup would be best for this car. Thank you for the help
junkyardhero
Well-Known Member
i'd trash that master and source one that i know to be correct for the application.
flip a coin on the distro block and buy used or grab a new one. the reports of them leaking are greatly exaggerated.
from the looks of all that plan on rebuilding everything and replacing the hardlines and soft lines.
flip a coin on the distro block and buy used or grab a new one. the reports of them leaking are greatly exaggerated.
from the looks of all that plan on rebuilding everything and replacing the hardlines and soft lines.
Update: I decided to make sure that my assumption that the car has 4 corner drums was correct. It was not. It's got discs up front and they seem original to the car. Should've checked that a long time ago. That means that the brake unit is a proportioning valve and not a distribution block, as I learned from someone's previous comment.
Another Update: Got the proportioning valve off the car. The model number is KH 89410(Kelsey Hayes). After looking it up, it seems like this piece is used on mopars. Any thoughts on rebuilding this piece and keeping it?
Another Update: Got the proportioning valve off the car. The model number is KH 89410(Kelsey Hayes). After looking it up, it seems like this piece is used on mopars. Any thoughts on rebuilding this piece and keeping it?
Might want to check with Cass @ www.doctordiff.com
He has some new ones for about 80.00 or so..
He usually responds to text messages
He has some new ones for about 80.00 or so..
He usually responds to text messages
Okay I will send him a text, thanks! I already started tearing this one apart because there's a video online showing step by step the process of rebuilding one and I thought it would be cool to learn. The only thing the guy doesn't show is how he removed the shuttle valve and I don't know how to remove it. I attached a pic of what it looks like.
JDMopar
Well-Known Member
Your proportioning valve is what would have come on your Roadrunner. I've had plenty of 72-73 Challengers and Cudas with that exact same valve. You can clean it out and rebuild it. I've got one just like it on my 71 Challenger conv. That car will stop on a dime and give you 9 cents change!
Good to hear haha. Do you mind taking a look at my post just before yours where I mention the shuttle valve? I have everything disassembled except for that. I'm not too sure how to remove that shuttle valve.
JDMopar
Well-Known Member
It would have to come out of one end or the other. Try taking the nut loose on the end with the little black rubber thing and see if it is under that. I was fortunate enough to have removed one that was on a car with a recently (at the time) working brake system, and it worked fine. If there's a plug in the other end, take it out too. You might be able to work the shuttle valve back and forth and get it out. It's probably got dried out and stuck O rings.
Edit: Not sure if this is the video you saw, but it's the same K-H valve you have. If you can find a Cordoba, Magnum, or Charger from the late 70's, they have the same valve. You might get lucky if the still have brakes and they could have the 11.75 rotor brakes. All you'll need is the caliper brackets if your car is 73 and up. If it's 71-72, grab spindles and all for a cheapo big brake upgrade!
Edit: Not sure if this is the video you saw, but it's the same K-H valve you have. If you can find a Cordoba, Magnum, or Charger from the late 70's, they have the same valve. You might get lucky if the still have brakes and they could have the 11.75 rotor brakes. All you'll need is the caliper brackets if your car is 73 and up. If it's 71-72, grab spindles and all for a cheapo big brake upgrade!
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