Do Proportioning Valves Wear Out?

-
pacuda59

pacuda59

pacuda59
Joined
Sep 20, 2005
Messages
5,790
Reaction score
813
Location
Pennsylvania
I'm converting my drums to discs off of a 75 Dart. I picked up the upper control arm, spindles and proportioning valve. Can I reuse the proportioning valve? Not sure if they have a life span.
 
Drum brake cars do not HAVE a prop valve. They have a combination distribution block and warning switch. You can buy an aftermarket adjustable valve, and add it in.
 
Sorry, I guess i wasn't clear. Among the parts picked off of the 75 Dart donor car is a proportioning valve. Since the valve is 38 years old, I'm wondering if they wear out? Should I plan on picking up a new one or use the one from the donor car?
 
If it were me, I would not even use that. I would do as I said, buy an aftermarket valve. They are not very expensive.

I WOULD be concerned about rust and corrosion in a piece that old, and the factory ones are not adjustable.
 
Nope, they don't wear out.

And, they're not even steel, so the only rust in them will be deposited from the brake fluid carrying it from other places.

They do plug up from all the crud in the lines, but if you clean it out well it shouldn't be an issue.
 
72bluNblu said:
Nope, they don't wear out.

And, they're not even steel, so the only rust in them will be deposited from the brake fluid carrying it from other places.

They do plug up from all the crud in the lines, but if you clean it out well it shouldn't be an issue.
Click to expand...

X2 They are made of brass and can be cleaned out and I believe internals can be replaced.
 
I am in the process from converting from 4 wheel drums to 4 wheel discs. Based on my research, I wouldn't stick with an old prop valve. I'd recommend getting an adjustable prop valve, like this Wilwood I picked up. In the long run, I think you'd be better off, especially if you route all those brake lines and you get a car that locks up the rear before the front. http://www.summitracing.com/parts/wil-260-11179
 
Hope that this isn't too far off of topic...Did any A-bodies have a combination valve(proportioning valve and distribution block, all in one). From looking at catalogs there was a hold off valve inline to the rear brakes on disc brake cars, which would serve the same purpose as a prop valve just not adjustable, correct?
 
The outer housing might be brass but all the internal stuff "ain't." It's a high pressure control valve of sorts. Anybody thinks something like that can't wear out is kidding themselves.
 
Judge Mills said:
I am in the process from converting from 4 wheel drums to 4 wheel discs. Based on my research, I wouldn't stick with an old prop valve. I'd recommend getting an adjustable prop valve, like this Wilwood I picked up. In the long run, I think you'd be better off, especially if you route all those brake lines and you get a car that locks up the rear before the front. http://www.summitracing.com/parts/wil-260-11179
Click to expand...

Just don't forget the residual valve if you use drums with that valve. Disks don't need them, but drum brake systems require residual pressure in the lines. Most of the drum valves are around 10 psi. Also, keep in mind that you probably can't use stock brake lines with that valve, so you'd have to make your own...

67Dart273 said:
The outer housing might be brass but all the internal stuff "ain't." It's a high pressure control valve of sorts. Anybody thinks something like that can't wear out is kidding themselves.
Click to expand...

Actually, most of it IS brass, as you can see from the rebuild link above. The springs aren't, and of course the seals aren't. But seriously, this is an extremely low wear item. I'd have no heartache whatsoever about running a used one that was cleaned up a little as long as it still had brake fluid in it when it was pulled (ie, seals aren't dried up). In fact, lets see, I've never changed one. Which means I actually am running several used ones right now. My challenger has somewhere around 136k miles on it (40k are mine), my Duster has 91k miles on it, the EL5 GT has 81k miles, and my latest project (shhh!) has around 124k miles. All of them work just fine...

zkx14 said:
These guys have the kit and here's the instructions to rebuild.

https://www.musclecarresearch.com/1970-76-mopar-combo-valve-rebuild
Click to expand...

Awesome. Great info there!
 
finelines sells new switches for them. I have used many used disc prop valaves and never had an issue,just blow it out with brake cleaner then blow it out with air.
 
Its brakes ! Damn people :( I hate to loose my religion on Sunday morning but...
Here's the very first thing one is taught in brake school. "Everyone is better off with a vehicle that wont go than a vehicle that wont stop".

To the thread starter... You haven't questioned reusing the master cylinder, wheel cylinders, fluid lines, from the donor. Apparently you are renewing those.
I wont ask why the proportion valve isn't considered the same.
Do this for us... Look in any factory service manual for instructions on servicing a proportion valve. You will find only that it is not to be serviced.
I'm sure your next question is, "So why does someone build and offer a kit with instructions ?" Short answer is "If you build it they will come".
Better answer is, The same reason someone built a solid state regulator and then told owners all they needed to do was bend a little thingy. They want your money and nothing more.
The internet is like a horse stable. The chit is dropped there to stay. No way to clean it up. Anyone who wishes to dance in the chit need only to google or ask in a public forum for the appropriate tune and dance steps.
For 6 years I have taken others by the hand and led them safely and quietly around all the chit. They came out the other end of the stable to carry on, nothing less than happy moparing ahead. That was/is my only goal. It stems from love for these cars and their owners, not pictures of dead presidents.
Now ending this sermon
You have 2 options, forget you ever started this thread and buy a new proportion valve or.... dance.
 
Does the sermon count for church this morning...lol?

Thank you Redfish, I appreciate your candor. Actually, from the 75 Dart donor car I've acquired the upper control arm, spindle, rotor, caliper dust shield, hoses and proportioning valve. I'm planning on replacing the hoses and wasn't sure about the prop valve.
As you might have noticed, I'm a novice mechanic with much to learn. Subsequently, I've decided to let my mechanic do this job precisely for the reason you opened you reply with......."it's brakes". I don't want that nagging feeling in the back of my mind as I'm cruising "did I put everything where it belongs"?
At this point in the project, I want to hand off all of the parts necessary for him to complete the job.
 
RedFish said:
Its brakes ! Damn people :( I hate to loose my religion on Sunday morning but...
Here's the very first thing one is taught in brake school. "Everyone is better off with a vehicle that wont go than a vehicle that wont stop".

To the thread starter... You haven't questioned reusing the master cylinder, wheel cylinders, fluid lines, from the donor. Apparently you are renewing those.
I wont ask why the proportion valve isn't considered the same.
Do this for us... Look in any factory service manual for instructions on servicing a proportion valve. You will find only that it is not to be serviced.
I'm sure your next question is, "So why does someone build and offer a kit with instructions ?" Short answer is "If you build it they will come".
Better answer is, The same reason someone built a solid state regulator and then told owners all they needed to do was bend a little thingy. They want your money and nothing more.
The internet is like a horse stable. The chit is dropped there to stay. No way to clean it up. Anyone who wishes to dance in the chit need only to google or ask in a public forum for the appropriate tune and dance steps.
For 6 years I have taken others by the hand and led them safely and quietly around all the chit. They came out the other end of the stable to carry on, nothing less than happy moparing ahead. That was/is my only goal. It stems from love for these cars and their owners, not pictures of dead presidents.
Now ending this sermon
You have 2 options, forget you ever started this thread and buy a new proportion valve or.... dance.
Click to expand...

Yes, its brakes. And I too have jumped on the soapbox a time or two (ok, maybe even more than that) regarding brakes. But if you use that standard to the absolute level, then you should replace every single component involved with braking every single time you buy a used car regardless of its operational status, mileage, etc. After all, those brake parts are used. :shock:

Or you could apply some logic, sound reasoning, and even some scientific method instead of just jumping on the soap box.

Its an extremely simple part. Yes, it has a couple of moving pistons and some seals. But if it doesn't leak, and fluid goes in the input and comes out of the outputs, the worst thing that can happen is the proportioning balance is off. Which is pretty easy to test (and you SHOULD test it). And it CAN be adjusted using the proper bleeding procedure, which re-centers the prop valve if its working properly.

So seriously, if it doesn't leak and isn't plugged, test to make sure the proportioning is fairly well balanced and run it. You're way better off running a used proportioning valve than you are buying a rebuilt master cylinder- the latter may have been sleeved incorrectly, not sleeved if it needed it, rebuilt multiple times, and not tested once it was "rebuilt". I've had far more problems with "reconditioned" master cylinders than I have with untouched prop valves.

Just because something is "new" doesn't mean its good, and just because something is "used" doesn't mean its bad. This is especially true now, with the quality control of new parts being somewhat questionable in many cases.
 
Yeah I knew I would be flamed. Your opinion of my comments is not relevant to the question. You wont generate an argument with me in this members thread or anywhere else. Sorry
 
RedFish said:
Yeah I knew I would be flamed. Your opinion of my comments is not relevant to the question. You wont generate an argument with me in this members thread or anywhere else. Sorry
Click to expand...

Hey, I'm not trying to flame you or start an argument. We've talked before on lots of different topics, many of which you've provided me with great knowledge on. So I deleted my "not relevant" comment from my earlier post.

I did assume that all of the "dancing" in the excrement comments were meant for my posts, and I do think that's kinda lame. Which may have skewed my tone a bit. :eek:ops:

But if you look at my post in response, other than the comment I deleted, it's strictly meant to point out that while there are lots of components that should always be replaced, the prop valve isn't one of them. Which is why I explained how I go about checking to make sure they work in the first place.

I wouldn't put info out there if I thought it was dangerous. All of my cars have used prop valves. I've put over 40k miles on my Challenger in the last 5 years as a daily driver, and I sure as heck wouldn't drive it if I couldn't stop it, especially in California traffic. Which is why I have 11.75" rotors and 11x2.5" drums on it, why every suspension part on it has been replaced or reconditioned, why I run modern spring rates and tires, and which is why I tell everyone to upgrade their brakes/suspension/tires to the best they can afford. But if you just wholesale replace everything, including working used parts, it limits what you can afford.
 
Reproductions are available for $100 at Classic Industries. Not sure of quality though.

http://www.classicindustries.com/mopar/parts/md2268.html

I bought a used one off this site not realizing aftermarket valves were available, and not wanting to have to mess with plumbing an adjustable one. Turns out the rear port on the used one was plugged.
 
Distribution or brake warning block would be for drum only, which is what he is replacing. The '75 with disk/drum would have a combination -brake warning/proportioning valve. That is what the factory service manual calls it.
 
We cant know a used valve is good without trying it. If I pull a working part and carry it across the shop and install it on another, I would be disappointed if it died in transit.
Most of the members here are dealing with parts that came out of the mail box, junk yard, dusty shelf where it has laid for several years, D; all the above.
Would I bother to install such a part ? That depends on what part it is. A rear end ? maybe, A power window motor ? No A brake fluid related part ? No.
Especially not the most difficult to R&R of them.
 
You must log in or register to reply here.
-

Back
Top