Bypass and remove the "height sensing" proportioning valve?

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

wczimmerman

Member
Joined
Aug 28, 2013
Posts
45
Reaction score
2
Location
Bothell, WA
First Name
William
Truck Year
1987
Truck Model
V2500
Engine Size
5.7L
Hello everyone,

I was out doing some rear axle maintenance today and noticed that the rear proportioning valve was wet. So, I moved the linkage and quickly got drips from the valve itself (not the lines going into it). This part has obviously failed. Nobody has a replacement and I've read that GM had a TSB for the 1 ton Suburbans/trucks to simply remove the part. My question is this: is it possible to just remove the lines and add some sort of connection between them in its place without cutting the existing lines? My truck is a V2500 3/4 ton 4x4 Suburban.

Thanks!
 

Keith Seymore

Full Access Member
Joined
Jul 13, 2015
Posts
2,641
Reaction score
8,137
Location
Motor City
First Name
Keith Seymore
Truck Year
1987
Truck Model
R10
Engine Size
4.3L
Absolutely.

It was a test beater put in place solely to pass FMVSS 108 in the days before ABS.

Get rid of the valve and all of the claptrap linkage.

K
 

foamypirate

Full Access Member
Joined
Jul 30, 2010
Posts
3,302
Reaction score
453
Location
Central TX
First Name
Jake (Mr. Wilson)
Truck Year
1980
Truck Model
El Camino, baby!
Engine Size
5.3L/4L60E
Last edited:

wczimmerman

Member
Joined
Aug 28, 2013
Posts
45
Reaction score
2
Location
Bothell, WA
First Name
William
Truck Year
1987
Truck Model
V2500
Engine Size
5.7L
Well, since I don't have the tools and time to fix this, I brought it to the mechanic that handled the motor swap for me. He's done great work but today he let me know that GM decided to make one of the lines 9/16" which is apparently a very odd size. The custom hydraulic line shop he uses didn't have anything to reduce it to the size of the other line (the main brake line from the master cylinder). So, at this point he's thinking of using 1/4" union from the main brake line and running about 3 ft of new brake line to the T connector in the back.


Here's a picture of the culprit:
You must be registered for see images


If I recall correctly, the line to the back T connector is on top and the main brake line from the master cylinder is on bottom.

Anyone have any other creative solutions?
 
Last edited:

foamypirate

Full Access Member
Joined
Jul 30, 2010
Posts
3,302
Reaction score
453
Location
Central TX
First Name
Jake (Mr. Wilson)
Truck Year
1980
Truck Model
El Camino, baby!
Engine Size
5.3L/4L60E
No creative solution required! Check my post above. You literally just have to slightly bend the main line from the frame rail and it will screw right into the rear brake hose!
 

wczimmerman

Member
Joined
Aug 28, 2013
Posts
45
Reaction score
2
Location
Bothell, WA
First Name
William
Truck Year
1987
Truck Model
V2500
Engine Size
5.7L
No creative solution required! Check my post above. You literally just have to slightly bend the main line from the frame rail and it will screw right into the rear brake hose!

I did look at thay but, sadly, my V2500 setup is slightly different. The rear brake hose isn't mounted like yours. Take a look at the picture in my post and you'll see what I mean.
 

foamypirate

Full Access Member
Joined
Jul 30, 2010
Posts
3,302
Reaction score
453
Location
Central TX
First Name
Jake (Mr. Wilson)
Truck Year
1980
Truck Model
El Camino, baby!
Engine Size
5.3L/4L60E
Ah, I'm at work so the photo is blocked. Bummer that won't work for ya.
 

Forum statistics

Threads
42,185
Posts
910,910
Members
33,678
Latest member
tnahaus
Top