Quick question manual to power brakes

[jponfrank]

I have a 1975 c10 manual brakes. Disc in front,drum in rear. I bought the kit which includes booster,master cylinder and valve. My question is do I remove the old proportioning valve or can I leave it alone. Thanks Joe

[Bigstevex4]

A little trick get the part # for it for power and non power brakes. you'll have the answer if its same or different.

[jponfrank]

I think Im missing something here. Can you use 2 valves or need to eliminate the orginal valve.

[greg64]

I suspect the proportioning valves are the same, but I'm not positive. What bigsteve is getting at is if you look up the part number for the prop valve for power brakes vs non power brakes, you can see if the same part number comes up. Give rockauto.com a try.

[Titomars]

Originally Posted by jponfrank

I have a 1975 c10 manual brakes. Disc in front,drum in rear. I bought the kit which includes booster,master cylinder and valve. My question is do I remove the old proportioning valve or can I leave it alone. Thanks Joe

according to the GM parts manual the prop. valve for 75 is the same for JB1 (manual) and JB3 (11X2 power). It does change numbers with JB5 (11.15X2.75 power) which weren't offered without power.
So assuming you got a kit that converts to JB3 power brakes you are good without changing the prop valve.
But if it were me I would use everything in the kit anyway. I don't short cut my brakes.

[Bigstevex4]

Originally Posted by greg64

I suspect the proportioning valves are the same, but I'm not positive. What bigsteve is getting at is if you look up the part number for the prop valve for power brakes vs non power brakes, you can see if the same part number comes up. Give rockauto.com a try.

Ya sorry My explain /Typing skills are lacking. Exactly if both setups use the same valve. I would not change it but that's not always the best. If they sent a new one up to you.

[jponfrank]

Thanks guys for clearing that up