Brake system

[KMC3420]

I am in the process of bending/routing my brake lines/hoses. I was looking for information on my next steps regarding Master Cylinder and proportioning valve. I found the below link as a good read just as an overview of the braking system. This is probably known knowledge for most but thought I would share it.

Brake Line bending tip

Brake system design

[robnolimit]

This image shows the use of both, a Combination valve (also known as a Metering block), as well as aftermarket valves (residual and proportioning valves). This can get you into trouble.

If you are doing a stock restoration using OE replacement brake parts, use the OE Metering block.

If your build is NOT a stock resto, then DO NOT use the Metering block. Use aftermarket valves only. Here are the rules. Use a 2lb residual valve for disk brakes, use a 10lb residual valve for drums. One for the front, one for the rear. Install an adjustable proportioning valve in the rear line. Valves should be as close to the master as reasonable.

[KMC3420]

Originally Posted by robnolimit

This image shows the use of both, a Combination valve (also known as a Metering block), as well as aftermarket valves (residual and proportioning valves). This can get you into trouble.

If you are doing a stock restoration using OE replacement brake parts, use the OE Metering block.

If your build is NOT a stock resto, then DO NOT use the Metering block. Use aftermarket valves only. Here are the rules. Use a 2lb residual valve for disk brakes, use a 10lb residual valve for drums. One for the front, one for the rear. Install an adjustable proportioning valve in the rear line. Valves should be as close to the master as reasonable.

Thanks Rob for the insight, I do appreciate it. The metering valves are just shown in the above picture to show location I believe, not really sure... I will be running disc/disc on a stock resto using M/C combination valve(Metering Block), my only question is, are residual valves required if your M/C is located in the stock location on the firewall and you are using the stock metering block? I will be installing the adjustable prop valve for the rear lines, the one that Wilwood makes.

[LS short box]

Not to mess up the original post but why the 2 lb residual valve in the front line when running disc/disc?
On my last few LS swaps I've used C5 discs front and rear without a residual valve and they have worked very well. I have always used an aftermarket prop valve mounted right under the master cylinder. Few medium and higher stops to adjust and it's been good to go.

[KMC3420]

Originally Posted by LS short box

Not to mess up the original post but why the 2 lb residual valve in the front line when running disc/disc?
On my last few LS swaps I've used C5 discs front and rear without a residual valve and they have worked very well. I have always used an aftermarket prop valve mounted right under the master cylinder. Few medium and higher stops to adjust and it's been good to go.

After doing lots of reading, I cant find examples of residual valves being used in braking systems, except for the ones who run a M/C-Booster mounted on the frame under the cab. My plan now is to not use any. Hope I am not missing anything by doing this?

[62 mark]

How about those of us using a newer master. I'm putting a 99 disc drum unit in my 62,disc drum,and I am unsure if the newer master is front port to front brakes,rear to rear.

[Bob@ProAuto]

Residual valves are are basically ball-spring check valves. They keep a small amount of fluid pressure in the lines.
If the fluid level in the master cylinder is lower than any other part of the brake system (bleeder screws, lines, etc.), then the fluid can gravity feed back into the master cylinder. This makes you pump the pedal to get the fluid back up and build some pressure.

[KMC3420]

Originally Posted by Bob@ProAuto

Residual valves are are basically ball-spring check valves. They keep a small amount of fluid pressure in the lines.
If the fluid level in the master cylinder is lower than any other part of the brake system (bleeder screws, lines, etc.), then the fluid can gravity feed back into the master cylinder. This makes you pump the pedal to get the fluid back up and build some pressure.

So a fail safe to ensure no pedal pumping is required is to run Residual valves? As Rob states, run them as close the M/C as reasonably possible? Just want to make sure I am doing this right as brakes are no place to skimp!

[Bob@ProAuto]

If your master cylinder is on the firewall (fluid level higher than caliper/drum bleeder screws), you don't need residual valves.

[The Rocknrod]

I had a pair I was going to put on, a local guy with a 64 did not put them on. He insist they're not needed also. He drives his daily.

[KMC3420]

Thanks Bob and Rockn, I appreciate the info. I don’t plan on using them for now as long as I don’t have any pedal pumping action needed in the future. I am learning the braking system is quite complex, but I’m enjoying learning.