Rear brake load propportioning valve adjustment

[86m10086.2L]

I just lifted my 86 k30 and much to my dismay, while finishing up the rear of the truck and getting ready to connect the linkage for the rear proportiong valve I watched as my brother spun the valve to "see if it was free and working" So now armed with no knowledge of where it was originally positioned. I set it where I thought it should go and put everything back together. Well, the brakes haven't been the same since. can anyone tell me how to adjust the valve so I can get my brakes back? I'm not removing it so don't waste your time telling me to get rid of it. The brakes worked great with it there, so it stays. Any help would be greatly appreciated.

 

[4X4HIGH]

Well, you've ruined my answer so now i can't help you.

 

[sweetk30]

do a search and you will not find much. with that everyone basicly pulls it as thay dont work/rust out/or not needed. and in the end almost all if not all say its better than when it was there.

all it use to do was adjust flow to rear with weight in the truck. so if your truck is not going to be used to haul stuff then you wont need it. and i would rather have all the brakes avalible to me cause of crazy drivers on the roads anymore.

 

[Jimbo*]

Turning it all the way counter-lockwise will make it free flow. The lever would turn the stem counter-clockwise under load, thereby allowing more fluid (less restriction) to the rear brake cyclinders.

If this is not what you want, find the middle point and experiment from there.

Most have been removed or bypassed.

 

[86m10086.2L]

Thats a start but whats the starting point? Does it matter? is there any suggested number of turns to make? Does this reset it? I will try some different settings with your info and see waht happens. Are they nor supposed to free wheel 360 deg ? Mine does, but a one point you hear and feel a slight click? Is that full open or closed?

 

[Jimbo*]

If I remember correctly, it should make 1.5 revolutions stop to stop. Any more than that and it is no good. I took one apart to see how it worked, and found it to be a rather fragile screw type valve. GM found them to be problematic also, discontinuing their use.

 

[dyeager535]

GM actually has some sort of plastic installed in them new IIRC, and that is what "sets" them from the get go. From there I think they mark them or something on disassembly. I remember it was a pain, my dad dealt with it when doing his rear disks, and there is a section in the service manual about it.

If you want, I can check it out, to see if there is a way to actually find "center", but I suspect there is not a book answer for that. But free to check on.