Technical Do I need a proportioning valve for drums all around

I recently bought a brake booster with dual m/c. Right now just have manual brakes. One day will like do disc but one thing at a time. My question will I need a proportioning valve now or should I wait? If not needed do I just reroute front and rear lines to dual mc. Thanks for belp.

 

All stock drums, original to the car, with just an upgraded master cylinder (dual circuit) and a booster?

If so, no. You haven't altered the brake bias.

If the drums are from disparate sources, yeah, probably.

You just need to re-plumb the lines to accommodate two fluid sources, F/R, instead of just one.

If your master cylinder is not equipped with residual pressure valves, you will need to add them inline. Look in the outlets and see if you see a rubber "beak" inside the cone.


If there aren't br*** cones in the port, ***ume it does not have residual valves.

 

Nope just switched to a dual master on my 55 ford has the stock drums all around and no need for a prop valve.

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Ok thanks guys for fast responses. If I do plan on doing a front brake disc in the future should I still wait or should I just get this out the way?

 

No. wait. Don't install something you don't need right now. Wait until you are ready to install disc brakes and do it all at once. This ensures all the parts match regardless of whether you get a kit or pick out the proper pieces by them self

 

K cool thanks for the advice

 

I just did brakes recently on my truck with booster it had all original stuff single line and all. So I upgrade to a Corvette style m/c with booster and run all new brake line. (Nicopp) stuff and I kept my drums of co**** replaced shoes and ect... I did put residual valves and an adjustable prop valve. Wildwood kit on that. Good luck.

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If the master you bought does have an internal RPV for the front brakes do you know for a fact that the supplied m/c is for drum or disc brakes? If you cannot determine that and it happened to be a drum master then it will be a 10# RPV. When you do switch to discs that will be too high a pressure and the calipers will drag. If you don't know which you have it just might be wise to pull the RPV from the master now and install an in line 10# valve, then when you do change over put in a 2# RPV.

 

https://m.summitracing.com/parts/sum-760199. This is kit I got. I'm not sure what rpv comes with it.

 

That just a Corvette style m/c and booster. Same exact like mine. If you keep drums put 10 psi residual valves and disc take 2 psi. And prop valve is mainly for back tires so you don't lock up in the back before the front.

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It comes with none. You will need to add 1 10psi one to the front line, and 1 10psi one to the rear line.

 

Ok sounds good. Thanks everyone

 

JFYI, USA dual master cylinders never came with disc brake residual valves, because modern discs (discs that use no return springs) never used or needed residuals with firewall-mounted masters that became the norm in the '50s, long before production discs. The 2 lb. residual is strictly aftermarket, intended only for low/below floor master locations with discs.
Production drum residuals varied in psi value-the aftermarket 10 lb. inline valve is simply a ball park value.

 

Thanks for clarifying that Bob. When I posted I didn't know if the master would be firewall or under floor mounted and I should have added that qualifier to my post.

 

I want to bring this back to the top, as I need to a new master, and the factory single master is $170, vs getting a safer dual for less than $50.

I am keeping all four drums as well. Do I ONLY need a 10 lb RPV for the rears? Or both? 1952 Oldsmobile Rocket 88

 

Both. They are not about which circuit they are on. The need to be on any circuit that has wheel cylinders. The 10psi keeps the flap seals in the wheel cylinders slightly loaded, to keep them sealed.

 

http://www.jegs.com/i/JEGS-Performa...4&cadevice=c&gclid=CJ_vhPvT49QCFQwQaQodCBYClA

Excellent, thank you!

 

That master cylinder is handy, as it has potential outlets on both sides.

 

And considering I just ordered it AND the proportioning valves for 1/2 the price of the bone stock single chamber one. Will take some fabrication work, but saving $$$$ and increasing safety. Win-Win.

 

If you are not changing your brakes from stock, you will not need the proportioning valve, just the master cylinder, and the residual valves. If you match the bore of the master cylinder, your brakes will feel exactly the same, but safer.

 

Residual valves. One on each circuit if all drums 10psi. Disc and drums 2psi on disc circuit 10psi on drum circuit and on rear you can run an in line adjustable valve so the rear can have adjustable pressure

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I matched the bore - 1". And I mis-spoke. These are what I ordered:

 

what master cylinder did you use thank you