Mechanics

HEIGHT SENSING PROPORTIONG VALVE

1987 Dodge Dakota

Brakes problem
1987 Dodge Dakota 6 cyl Two Wheel Drive Manual 187k miles

I bought this truck (87 dodge dakota 2x4 for $300, pretty good condition, considering the year and climate. However, the brake system did not fare as well as the rest of the truck. In particular the HSPV. It is badly rusted and 2 brake lines have snapped off in the valve, so I either get a new one at $289, replace the lines and prorobly the wheel cylnders and calipers( those bleeder screws look bad too)
By this time I'm looking at close to 2x if not more than I paid for the truck.
I came up with the idea of bypassing the HSPV. I would connect the primary line directly to the metering valve on the rear axle, and simply plug the bypass line at the differential/metering valve up front. After which I would adjust the rear brakes so as to try and prevent them from locking up as much as possible. I know this is not recommended, but my question is. Would this work?
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Alxx72
April 29, 2008.




It might. But why don't you just cut the line off as close to the end, and use a socket to remove the flare nut portion?

Merlin2021
Apr 29, 2008.
The line broke off flush with the valve

Tiny
Alxx72
Apr 29, 2008.
Basically I wanna know that as long as I plug the bypass line up front I will get pressure to the rears?

Tiny
Alxx72
Apr 29, 2008.
What you would have to do is get a new brake hose long enough to mount it on the rear axle to eliminate the valve, Then branch off to the wheels. If you block it near the Master you wont get fluid at the rear. If the line broke at the valve, the nut is still there.I would do the above proceedure?

Merlin2021
Apr 29, 2008.
I think you are missing a part here. I have a preportiong/metering valve up front, 2 lines, a primary and a bypass line go down and just before the rear wheel there is a " height sensing proportioning valve" the 2 lines go into it, but have rusted away and broke off into it. Then 1 line goes to the metering valve on the rear axle. The valve on the axle (tee) is ok. The height sensing proportioning valve is what I am looking to bypass. I hope that helped

Tiny
Alxx72
Apr 29, 2008.
I just had the same thing kind of happen to my HSPV. Mine, all the lines are good, I just replaced them last fall. Now I noticed another leak on the back side of the HSPV. It's not leaking from the bleeders nor where the lines are coming in. Looks like there is a hole on the back side. Someone told me that the hole might be there for when the valve goes bad it will leak out of the hole? I too looked into replacing the HSPV. Same prices too! I believe I am going to bypass the HSPV and run direct to the splitter on the rear axle. My question is which one is the back line and which is the return line. The front spllit has one line directly straight back to the HSPV and one comes out of the bottom of the Front Proportioning valve and goes to the back HSPV. Anyone know which line to leave and which line to Plug? I'm thinking the bottom one is the return line.
Thanks in advance, Dustyr26!

Tiny
Dustyr26
May 2, 2008.
The line out of the combination valve is the one to keep, block the other one.

Merlin2021
May 2, 2008.
Thanks,
The combination valve has the two lines coming back to the HSPV. I guess I'm just confused on which of the two to plug at the combination valve. I am assuming it should be the one coming straight back off the end of the combination valve. The other line which I would plug would be the one on the bottom. I will look a little closer once I get under the truck and try to get at it.

I probably will detach both lines back at the HSPV and then press on the brake to see which line shoots the brake fluid out, then that will be the one to connect to the line heading to the tee that goes to each rear tire. I would assume the other would then be the return line and plug that at the front at the combination valve.

Thanks again for the help. It's reassuring to pretend like I know what the heck I'm doing!

Thanks
Dustyr26

Tiny
Dustyr26
May 2, 2008.
It really would not matter which then, both will do the job! Choose the easiest one.

Merlin2021
May 2, 2008.
Yeah Dusty, that's exactly what I'm doing too. I would've been done already, but the weather here has been rainy. No chance to work on it.
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Tiny
Alxx72
May 2, 2008.

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