Bad Proportioning Valve?

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jtbartsch

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Feb 1, 2024
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Overland Park, KS
First Name
Joseph
Truck Year
1986
Truck Model
K10
Engine Size
350, 5.7L
I had to remove my proportioning valve and centre the spool so it wouldn't trigger the sensor. As much as it was a pain to remove and and adjust, it was cheaper than buying a new one. It took a bit of "shuttling" looking down the hole to see its centred. You're probably have to remove it and manually shift it.
When you removed the lines from prop valve, did you leave the cap on the reservoir to the MC? I was thinking of doing exact thing you described as I still have not gotten it to slide over, but I do not want my lines or MC to run dry and then result in needing to bench bleed the MC. Thanks
 

Cyrillious

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Toronto
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Cyril
Truck Year
1980
Truck Model
K10 Suburban
Engine Size
350
When you removed the lines from prop valve, did you leave the cap on the reservoir to the MC? I was thinking of doing exact thing you described as I still have not gotten it to slide over, but I do not want my lines or MC to run dry and then result in needing to bench bleed the MC. Thanks
The cap you mean the top brake warning sensor wiring? I squeezed the sides to remove the wire cap from the white plastic sensor and removed the lines and removed the whole assembly.

Removed left and right ports to allow you to Move the shuttle/spool. In order to see that it's centred you have to remove the sensor. With some light when you move the spool/shuttle left or right with some fine tools you can make sense of where the middle section is which is the deepest part, which you want, so the sensor does NOT touch the spool to ground and trigger the warning light again.

Put it all together and fill the reservoirs and start bleeding the lines! Your lines should be fine. Just extra bubbles to extract when time to bleed. Hope this helps and makes sense.
 

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