1970 Challenger Proportioning valve and metering valve ??

[WX Martin]

I'm trying to solve the dilemma of no fluid getting to my rear drum brakes. Discovered the problem after adding a right Stuff Booster for my front discs. I'm searching for parts but seem to be having trouble finding out what they actually call the valve on my rear axel that feeds the rear brakes. I see it sometimes called a Mixing valve, or a proportioning valve or a balancing valve. Sometimes they are pictured attached to the engine bay proportioning valve. My mechanic is good but he is a GM and Ford guy . Any help with the correct name especially for the rear axle valve is much appreciated. Thank you in advance

 

[Ralph]

Check the year one catalog for proportioning valve and rear axle connector I believe. There are good pictures and diagrams as well in the catalog.

 

[Rapidfire]

Should look like this?!

 

[WX Martin]

Yes. I have the Service manual as well. Difficulty is in the product ID Year One list them as distribution blocks. Classic has another name. Sometimes same picture with different ID. Summit and Jegs list replacement options that are not OEM but that I'm sure would work too.

Thank you

 

[Rapidfire]

Try searching for "rear axle brake line tee" thats basically what it does and is held on with the threaded vent tube.

 

[WX Martin]

Try searching for "rear axle brake line tee" thats basically what it does and is held on with the threaded vent tube.

This one is actually a spring loaded metering valve

Try searching for "rear axle brake line tee" thats basically what it does and is held on with the threaded vent tube.

This one is actually a spring loaded metering valve that prevents rear brake lock up . The stock one is not adjustable. Aftermarket ones are adjustable but that's trial and error. Wondering if the stock ones are preset or if there are options
thank you again

 

[Rapidfire]

As far as I know the main proportioning valve should control the front and the rear about 60/40 respectively. You can buy aftermarket to tweak the settings. You might have a plug in your line. Check your flex hose coming off your body and going to your axle distribution block as it could be collapsed. I have ran into that before on new and old hoses. Hard to tell unless you pull it and blow air thru it. I would start from the back and work my way forward.

 

[70chall440]

I just read through this thread and it seems there is some confusion (or maybe it is me that is confused). The block located on the rearend is merely a Tee, it is connected to the rear hard brake line via a rubber line, it then splits the rear brake line into 2, one for each rear brake. There isn't anything inside of it. It is held to the rearend by the rearend vent.

Under the master cylinder you have or can have a variety of valves or blocks depending on year and brake system. However, for Mopars is comes down to basically 2 or 3, you will have a combination valve (aka proportioning valve), a metering valve and/or a distribution valve. Generally speaking, the metering valve is found on cars with drum/disc set ups, it is designed to reduce the potential for the rear brakes to lock up before the front. However, later cars (72 ish) incorporated this feature into the P valve, thus calling it a combination valve. The distribution valve merely directly fluid to multiple locations (exactly like the block on the rearend).

In the combination valve (Proportioning valve) it might be possible that the actual valve inside is stuck in one direction or the other which will reduce or eliminate fluid getting to the blocked off side (circuit). I had this happen on my Cuda and ended up replacing it with one designed for a disc/disc setup which is what I am running. I am doing this right not for a 69 Plymouth station wagon as well.

 

[WX Martin]

As far as I know the main proportioning valve should control the front and the rear about 60/40 respectively. You can buy aftermarket to tweak the settings. You might have a plug in your line. Check your flex hose coming off your body and going to your axle distribution block as it could be collapsed. I have ran into that before on new and old hoses. Hard to tell unless you pull it and blow air thru it. I would start from the back and work my way forward.

Thank you. Good suggestion

 

[WX Martin]

I just read through this thread and it seems there is some confusion (or maybe it is me that is confused). The block located on the rearend is merely a Tee, it is connected to the rear hard brake line via a rubber line, it then splits the rear brake line into 2, one for each rear brake. There isn't anything inside of it. It is held to the rearend by the rearend vent.

Under the master cylinder you have or can have a variety of valves or blocks depending on year and brake system. However, for Mopars is comes down to basically 2 or 3, you will have a combination valve (aka proportioning valve), a metering valve and/or a distribution valve. Generally speaking, the metering valve is found on cars with drum/disc set ups, it is designed to reduce the potential for the rear brakes to lock up before the front. However, later cars (72 ish) incorporated this feature into the P valve, thus calling it a combination valve. The distribution valve merely directly fluid to multiple locations (exactly like the block on the rearend).

In the combination valve (Proportioning valve) it might be possible that the actual valve inside is stuck in one direction or the other which will reduce or eliminate fluid getting to the blocked off side (circuit). I had this happen on my Cuda and ended up replacing it with one designed for a disc/disc setup which is what I am running. I am doing this right not for a 69 Plymouth station wagon as well.

Thank you. I have the standard proportioning valve under the master. No additional metering or distributing block there as you have mentioned or as I have seen in some online reference sites I do have the tee on the rear axle but mine has the spring loaded balancing valve ( you can see the dust cover in my Pic above) I see now that Year One does list a matching replacement . I think I'll crack the line feeding into the tee and see what I get. Then open at the proportioning valve under the master .. That done I'll be able to force air through the line to rule out a blockage as has been suggested and also check the proportioning valve function. I'll also check my rubber lines

Thanks to all for the good suggestions

 

[340challconvert]

This may also help
Mopar Service Bulletins courtesy of (Hamtramck Historical)

 

[70chall440]

Thank you. I have the standard proportioning valve under the master. No additional metering or distributing block there as you have mentioned or as I have seen in some online reference sites I do have the tee on the rear axle but mine has the spring loaded balancing valve ( you can see the dust cover in my Pic above) I see now that Year One does list a matching replacement . I think I'll crack the line feeding into the tee and see what I get. Then open at the proportioning valve under the master .. That done I'll be able to force air through the line to rule out a blockage as has been suggested and also check the proportioning valve function. I'll also check my rubber lines

Thanks to all for the good suggestions

You are welcome, the thing you are calling a "spring loaded balancing valve w/dust cap" is actually the vent tube for your rear end. The dust cap is to keep crap out of the rear end housing. I've never seen a spring in one but I guess its possible. Has nothing to do with your rear brakes.

 

[bc3j]

I had the same issue with no fluid to rear. My rubber rear hose from the frame to axle tee was internally collapsed blocking flow.

I use the valving as shown above with the metering valve that was used after January 1, 1970 with no issues.

 

[WX Martin]

I had the same issue with no fluid to rear. My rubber rear hose from the frame to axle tee was internally collapsed blocking flow.

I use the valving as shown above with the metering valve that was used after January 1, 1970 with no issues.

That's great !!! Yes. I think I was assuming the fitting on the tee was the rear metering valve and not just a tee with a vent. I had assumed ( and I should know by now what that gets you ) that since it had manual front disc brakes and rear drums that there was already a rear metering valve installed. Double checked along the entire frame length to be certain and there is not. Now I'm clear from your article that mine has the new combination valve with warning light feature. As I'm doing and upgrade to power anyway I think I'll get a new Combination valve as they are available from Classic and Year One

Thank you for the post and the pic !

 

[WX Martin]

I just read through this thread and it seems there is some confusion (or maybe it is me that is confused). The block located on the rearend is merely a Tee, it is connected to the rear hard brake line via a rubber line, it then splits the rear brake line into 2, one for each rear brake. There isn't anything inside of it. It is held to the rearend by the rearend vent.

Under the master cylinder you have or can have a variety of valves or blocks depending on year and brake system. However, for Mopars is comes down to basically 2 or 3, you will have a combination valve (aka proportioning valve), a metering valve and/or a distribution valve. Generally speaking, the metering valve is found on cars with drum/disc set ups, it is designed to reduce the potential for the rear brakes to lock up before the front. However, later cars (72 ish) incorporated this feature into the P valve, thus calling it a combination valve. The distribution valve merely directly fluid to multiple locations (exactly like the block on the rearend).

In the combination valve (Proportioning valve) it might be possible that the actual valve inside is stuck in one direction or the other which will reduce or eliminate fluid getting to the blocked off side (circuit). I had this happen on my Cuda and ended up replacing it with one designed for a disc/disc setup which is what I am running. I am doing this right not for a 69 Plymouth station wagon as well.

Thank you. I suspect you may be right and I think I'll just replace it and play it safe