Residual valves are used even with firewall mounted MC's. The popular '67 Mustang drum/drum MC came with them from the factory. Their purpose is to reduce pedal travel by keeping the shoes/pads close to the drum/rotor, but not so much that there is a lot of drag. It also reduces air getting sucked in around the wheel cylinder / caliper bore seals.

A firewall mounted reservoir on one of our trucks is "maybe" 2-1/2 ft higher than the stock MC, which puts a little less than one psi pressure at the MC.

 

CPP did email back as well with the following reply:

"Hi Schuyler, the master does not have residuals in it, sometimes if the master cyl is lower then the wheel cylinders then you could put them in line."

 

Thanks! I've decided to put them in line and also use the remote reservoir.

Ain't nothing that can't be undone if necessary!

 

Some reading:

Residual Check Valve Function: Drum Brake System

Typical Brake System Configurations

 

Just a update to this post for those that refer to it in the future. Here is a copy of the instructions I received with my CPP proportioning valve. Item 2 under functions, 10 PSI residual valve. Don't know if this helps, but there it is.

 

Good info, is that for a drum-disc setup, or universal? Not clear if the 10 psi RPV is on the rear only?

 

Good job. I had read something similar since starting this thread, so seems like you can take it to the bank and save yourself $20 on the rear residual valve. I also read that it doesn't matter if you have two...hopefully that's true

 

Mine is a disc, drum setup. I am not going to run residual valves. Will see how it works.

 

I believe from all the discussions, you have figured this out now.

Personally I used the exact same set up of under floor master that is in your picture and installed a residual valve in line for both the front and back on my 56 F100 along with a remote reservoir installed in cab behind seat.

Have run this for nearly 10,000 miles now and no problems, brakes work fantastic..

Good luck and good trucking.

 

Good to know for peace of mind, thanks for the input!

I just have a few more parts to get and I will be in business.

 

I bought the cap from CPP on eBay and the reservoir on eBay as well. While it is probably a lot more of a "want" than a "need," I don't have any regrets yet! I just couldn't bring myself to use the plastic reservoir that came with the cap.

 

Your neighbor south of Nashville would like to know where did you source the reservoirs?

 

Howdy neighbor!

I can't be sure, because they were on eBay and didn't have a manufacturer listed or any markings on them.

But I can't help but notice they look exactly like these...

Scottshotrods | Scott's Hotrods Remote Reservoirs - Scottshotrods

I got a good deal ($50) but even the $135 (for triple) on the above website seems like a pretty good price!

 

Thanks. I will check those out. I am thinking about what you have or these.

http://www.summitracing.com/parts/wi...2697/overview/

 

Oh yeah, I definitely like that as well!