Quote Originally Posted by CPPAaron View Post
no need to remove the metering valve... This will do nothing for your your pedal travel. So again the issue would be too large of a bore master. 1" bore will limit the travel. The 1-1/8 with the big multi- piston calipers is causing your Excessive pedal travel.
Aaron; please explain. We tried the MCPV-1 1" bore master cylinder from CPP first. The pedal travel was LONGER (smaller bore = longer stroke to produce the same volume, but will have more mechanical advantage thus producing more pressure in the system with less pedal effort). A larger bore (1 1/8") produces the same amount of volume with a shorter stroke but will have less mechanical advantage requiring greater pedal effort. Please correct me if I am mistaken, but this is how I understand the physics behind it, and also how it was explained to me by several techs on the phone at CPP.

With the 1" bore, we had an excessively long pedal travel, and Mario along with several other techs at CPP recommended switching to the 1 1/8" bore to SHORTEN the travel- so we did. With the larger bore (1 1/8") master, the pedal travel is shorter. Regardless, the overall pedal travel is not the issue, as it is acceptable with the 1 1/8" bore master cylinder. The problem I would like to address is the amount of pedal travel required before the calipers actually start to engage on the rotors.

This brings me to the question I would actually like to discuss: the function and operation of this metering valve. Every other disc/disc system on the market does not require a metering valve. Metering valves are required with disc/drum systems in order to build pressure to the rear drums before allowing pressure to go to the front discs so both are engaged at basically the same time. Since I have a 4-wheel disc system, I believe this may be delaying the engagement of my front brakes, which is felt as 3-4" of travel before the calipers engage the rotors, which coincidentally is about the same as when the car had the disc/drum setup.

Every vehicle I have driven with a disc/disc setup only requires about 1-2" of pedal travel until the calipers begin to engage the rotors, and I suspect this metering valve may be the culprit. When CPP first introduced the MCPV-1 master cylinder, the instructions said to remove this metering valve for disc/disc brake setups. CPP has removed this from the instructions, and I cannot get an explanation as to why.

I wanted to know if this question could be posed the the engineer at CPP who designed the MCPV-1 (I forget his name, but I have spoken with him in the past through Mario about the master cylinder).

I want to say that everyone at CPP, especially Mario, has been extremely helpful thus far and have provided amazing customer service. I simply want to improve the operation of this brake system, and I would very much appreciate if someone could research the function of this metering valve. I would like to know if its removal would have positive or negative effects within the system- thank you.

Except from ORIGINAL MCPV-1 installation instructions calling for the removal of the metering valve for disc/disc systems:

mcpv1-02.jpg



Very Respectfully,

Matt Miller
CIFCO- Central Iowa Fabrication Company
miller54z@yahoo.com
386-846-0419