Re-use proportioning valve?

[Keith M.]

Would like some input on whether or not to re-use what I believe is the original proportioning valve from my car...see pix. My restore philosophy is to keep original parts unless either 1) they are so hideous that they significantly detract from the car, and/or 2) there could likely be or would be performance issues. In this case the valve is by no means pretty...but it's location is not in a place where that would bother me and I would prioritize keeping this original part....UNLESS I am potentially creating a likely leak problem that would require me to drain the brakes and then replace it anyway. Thoughts? And I guess same goes for the small brass blocks in the rear. If there is a reasonable chance they will perform ok then I prefer to keep. OTOH it IS the brake system so I need to keep that in mind. And re-using does save me the $90 or so for another one. I am NOT chasing awards so that is not a factor and please no comments about points this or that or awards.

If you feel it wise to replace, who makes the best repro? My sense is all the usual retail places are sourcing from the same place...or two...but who makes the best.
TIA
Keith

[Ron G.]

Re: Re-use proportioning valve?

Keith,

There is a company called Lone Star located in Texas. They specialize in rebuilding and remanufacturing brake part components. I had my original brake proportioning valve and power steering valve rebuilt by them. They did an excellent job and they made sure that I got my original parts back. The person that answers the phone will tell you to just send them in, but my recommendation is to ask to speak with Brad Lindsey. Brad will oversee and expedite the rebuild of your parts. Their reach number is: (903) 829 - 8400. If you do decide to use them, reference my name to Brad. - Ron

[Keith M.]

Re: Re-use proportioning valve?

Keith,

There is a company called Lone Star located in Texas. They specialize in rebuilding and remanufacturing brake part components. I had my original brake proportioning valve and power steering valve rebuilt by them. They did an excellent job and they made sure that I got my original parts back. The person that answers the phone will tell you to just send them in, but my recommendation is to ask to speak with Brad Lindsey. Brad will oversee and expedite the rebuild of your parts. Their reach number is: (903) 829 - 8400. If you do decide to use them, reference my name to Brad. - Ron

Thanks Ron!! That's great to know. I was not aware they did that service. I got my rebuilt correct brake calipers and master cylinder from them last year. And as it turns out steering control valve is just about out and I had them targeted for the rebuild. I can ask when I call but wondering if you are aware of any other services they are best for??

[Leif A.]

Re: Re-use proportioning valve?

Keith,
The item you refer to as a "proportioning valve" is actually called a Brake Distribution Switch & Metering Block Valve. It's job is to detect if one or the other of the master cylinder bowls is low/empty of brake fluid. The switch would then turn on your "brake" light on your dash to alert you.
Yours appears to be in serviceable condition...I would reuse it.
BTW, there was a proportioning valve used when J56 special heavy duty brakes were ordered.

[Duke W.]

Re: Re-use proportioning valve?

Any kind of leak on one side causing that side to loose pressure will move the switch and light the "brake" light in the IP.

Many cars of the era, especially those with disk/drum systems use what GM calls a "combination valve" that provided the differential pressure sensing with rear pressure proportioning.

Soak the valve in denatured alcohol for a day and then thoroughly dry, and it should be okay to use. You can probably use air pressure and an ohmmeter to verify that the switch functions.

Duke

[Keith M.]

Re: Re-use proportioning valve?

Thanks all. Consensus seems re-use...with some cleaning/prep first. Can I assume this applies to the smaller blocks in the rear....meaning good to re-use?

[Duke W.]

Re: Re-use proportioning valve?

The tee in the rear brake pipe just distributes pressure to both rear calipers - no moving parts, so okay to reuse if clean.

Duke

[Jeffrey S.]

Re: Re-use proportioning valve?

Keith,
Definitely keep your original. Yours appears to be dated the 273rd day of '69 (stamped into side). It is not hard to "liven" up the brass with Brasso or some other brass polish (Simichrome Polish, etc.) Be aware that the size of the line fittings on a '69 block are different than '70 and up. I don't have the sizes here but I do have several of both and they are not the same. If you send off yours for rebuilding be sure that they send the same one back to you.
Jeff

[Keith M.]

Re: Re-use proportioning valve?

Keith,
Definitely keep your original. Yours appears to be dated the 273rd day of '69 (stamped into side). It is not hard to "liven" up the brass with Brasso or some other brass polish (Simichrome Polish, etc.) Be aware that the size of the line fittings on a '69 block are different than '70 and up. I don't have the sizes here but I do have several of both and they are not the same. If you send off yours for rebuilding be sure that they send the same one back to you.
Jeff

Hi Jeff,
Holy smokes. I did see that stamped number but had no idea of stampings on these....ie. did not know of part # stamps nor date codes. If that is indeed a 1969 day...then it was Sept 30 which is ideal match up with my late Oct built car. Dunno what Lonestar charges but it probably worthwhile to get it looking purty and more importantly ensuring solid functionality.
Thanks so much,
Keith

[Richard M.]

Re: Re-use proportioning valve?

Here is a 1967 version. There is a small spool inside which moves when there is a differential in fluid pressures. It makes contact to the switch pin when activated.

This is what most look like..
P6300009.jpg
P6300012.jpg

Disassembly...
P6290001.jpg
P6290008.jpg
P6290007.jpg
P6290009.jpg

The only way to clean the internal spool is to remove it. The o-rings should be replaced also. Sizes below. Remove the brass insert on one end and push the spool out the other end. To remove the insert, Screw-Tap the center of the insert and make a puller from a old fitting and mating thread screw/washers. New inserts are available from some of the vendors.

Here's a folder of photos for reference, along with some notes.
P6300017.jpgP6300003.jpgP6300002.jpgP6300004.jpgP6300005.jpgP6300006.jpgP6300007.jpg

Assembly. The new brass inserts are installed using a appropriately sized fitting and simply pressed in until they bottom out. Originals can be reused provided they're not externally damaged.
P1170001.jpgP1170002.jpgP1170003.jpgP1170006.jpgP1170007.jpgP1170008.jpgP1170011.jpgP1170022.jpgP1170023.jpgP1170025.jpg

[Leif A.]

Re: Re-use proportioning valve?

Rich,
Your tutorials are masterful!!

[Owen L.]

Re: Re-use proportioning valve?

Rich,
Your tutorials are masterful!!

I'll second that - so helpful on how the components look and how they're assembled.

Does the switch pin just pull out once the nut is removed?

[Keith M.]

Re: Re-use proportioning valve?

Yeah...now that I know there is so much going on in there will definitely have Lonestar do a rebuild/restore.

[Richard M.]

Re: Re-use proportioning valve?

Rich,
Your tutorials are masterful!!

I'll second that - so helpful on how the components look and how they're assembled.

Does the switch pin just pull out once the nut is removed?

Thanks Gents.

On that one in my first post, after the threaded sleeve is removed the contactor just pulls out. This was from a March car.

I've done a few over the years. Some have differently configured pin switches. I'm unsure if these differences were due to different GM vendors making them or if the suppliers changed their designs over time. I suspect the latter.

Here is another type from a early '67(Nov built). As you'll see the switch is a different configuration.
PC230003.jpgPC230004.jpg

The contactor on this type screws into the threaded housing. Note the insulator sleeve around the slotted screw head.
PC250005.jpgPC250006.jpg

Center of the spool inside the case.
PC250008.jpg

Note the recess in the housing, made to fit the switch assembly o-ring to seal any escaping fluid if the spool seals leak.
PC250010.jpg

Of course the caveat is I don't truly know if these two I showed were definitely originals, but I suspect so.

Rich

[Keith M.]

Re: Re-use proportioning valve?

Do these things not have a "failsafe" built in? Or is that just with a true proportioning valve...or do those not either? What I mean is...I thought there were some devices that worked such that if the front or rear dropped pressure the light would kick on but the valve would ensure the "good" side ...front or back still functioned.