Neat 4wdb proportioning valve option

[Bonnewagon]

So I was faced with a derelict vehicle left in my Daughter's yard by a dumped X. 2002 Tahoe. Another friend wanted it and started to fix it up. When we were moving it the brakes failed. All the lines were corroded. We replaced them all with new. The ABS unit was fried anyway and we wanted to bypass it but how to get a four wheel disc brake proportioning valve to work with this? I snooped on RockAuto and spied this unit for a 2003 and up model. It is a 4wdb valve with a bracket that bolts to the master cylinder just like on F bodies. All I did was remove the MC nuts, install this bracket, and plumb the lines to it. I don't see why we can't use this on our cars when we convert to 4wdb. Sure beats searching for a 4wdb proportioning valve that can be mounted under the MC not on the frame. It is like someone figured out a way to bypass the $1000 ABS system cheaply and easily. I don't know why the '02 didn't list this but the '03 and up listed it and yet used the same MC. There are two versions and I chose the one that had 1/2" fittings same as the MC and it braked just fine. Part number is ACDELCO 15166885

 

[Bonnewagon]

UPDATE: The Tahoe made the three hour trip from NYC to South Jersey. Not a peep out of the brakes. It rained all day too and the proportioning valve worked as it should. All the wheels braked evenly with no skidding on the wet roads. Sounds like a winning part for a retro-fit into our cars.

 

[pontiacgp]

So I was faced with a derelict vehicle left in my Daughter's yard by a dumped X. 2002 Tahoe. Another friend wanted it and started to fix it up. When we were moving it the brakes failed. All the lines were corroded. We replaced them all with new. The ABS unit was fried anyway and we wanted to bypass it but how to get a four wheel disc brake proportioning valve to work with this? I snooped on RockAuto and spied this unit for a 2003 and up model. It is a 4wdb valve with a bracket that bolts to the master cylinder just like on F bodies. All I did was remove the MS nuts, install this bracket, and plumb the lines to it. I don't see why we can't use this on our cars when we convert to 4wdb. Sure beats searching for a 4wdb proportioning valve that can be mounted under the MS not on the frame. It is like someone figured out a way to bypass the $1000 ABS system cheaply and easily. I don't know why the '02 didn't list this but the '03 and up listed it and yet used the same MS. There are two versions and I chose the one that had 1/2" fittings same as the MS and it braked just fine. Part number is ACDELCO 15166885 View attachment 128849

excellent timing, I plan on doing the conversion this winter so you just found what I need...thanks...

 

[Bonnewagon]

so you just found what I need

That was my whole intention. I've seen lots of posts about what valve to use. All I could suggest was the '79- '81 Firebird 4wdb valve. But that one mounted under the MC and our cars mounted it to the frame. This set-up gets you a 4wdb valve and a bracket to mount it under the MC for less than $100. There were two versions: one was for with electronic braking control and one for without. The one with used 1/2"-20 inverted flare nuts just like the MC. The one without used .45" inverted flare nuts. I could not find what commonly available nuts that translated to. Closest I came was 11.5mm which "maybe" a 12mm x 1.0 nut would work. Easier to just use the 1/2"-20. The specs and parts pics on RockAuto failed to show that there were indeed five ports on the valve. Looking at it you would think there are only four so I ordered a Dorman inverted flare "T" fitting to split the front brake lines but didn't need it. Just be aware that the Tahoe used 1/4" brake tubing all around and the MC and valve are machined for that. IIRC our cars use 1/4" for the rear line. If you use 3/16" tubing for the fronts an adapter fitting would be needed. No reason not to use 1/4" line there too.

 

[clean8485]

Does MS mean master cylinder?

 

[Bonnewagon]

Yes. I apologize for my typing laziness. I suffer from old guy fingers. And I am stupid. Corrections made.

 

[TURNA]

Is it the same thread size as a GBody or is it metric?

Also no holes in it so it can not be mounted in stock location?

 

[Bonnewagon]

It is 1/2"-20. The other version might be metric. What does .45" convert to? No through holes. The bracket is mounted to the underside. https://www.rockauto.com/en/moreinfo.php?pk=3888777&cc=1412244&jsn=2314&jsn=2314&jsn=2314 and https://www.rockauto.com/en/moreinfo.php?pk=1568554&cc=1412244&jsn=2315