Brakes ideas for C20 - sanity check

[71threequarterton]

I've been lurking around here, reading up on tons of threads about brakes, been crawling under the truck inspecting and getting an idea of what I'm working with and I'm at a point where I want to buy some stuff. I want to rebuild the whole system.

I currently have 11" power booster and standard looking MC and prop valve with 3/16" lines to the front and 1/4" line to the rear along the frame.

I'm liking the Wilwood master cylinder and proportioning valve and I want to bend and flare my own NICOPP lines so here's the question: am I going to be OK with running 3/16" line to the rear?

I talked to a vendor and he said it's no problem. I think I read that somebody here has done that type of setup so what about it - does this seem like a reasonable way to go?

Thanks for any advice.

[Steeveedee]

Is the vendor a brake design engineer for GM? I'd put back the same size as came off. I worked as a mechanical engineer for many years. I don't second guess the factory engineers.

[71threequarterton]

Originally Posted by Steeveedee

Is the vendor a brake design engineer for GM? I'd put back the same size as came off. I worked as a mechanical engineer for many years. I don't second guess the factory engineers.

I'm guessing no, the guy is probably not an engineer. My thoughts are I should keep everything the same size. I just wanted to see if anybody else had done something like this.

[rockyrivermark]

Originally Posted by Steeveedee

Is the vendor a brake design engineer for GM? I'd put back the same size as came off. I worked as a mechanical engineer for many years. I don't second guess the factory engineers.

except for the ones that developed the evap system on 2000's trucks or the ones that developed the two piece spark plugs on mid 2000 F150's
sometimes improvements are warranted and sometimes not.
I replaced my entire braking system since the truck was sitting for a long time when i bought it. . Inlinetube.com stainless lines fit perfectly. Bought their entire set up, prop valve, etc. previous owner converted fronts to disc.
added rear disc afterwards.... that made a huge difference.
RRM

[S_Gibson]

Originally Posted by 71threequarterton

I've been lurking around here, reading up on tons of threads about brakes, been crawling under the truck inspecting and getting an idea of what I'm working with and I'm at a point where I want to buy some stuff. I want to rebuild the whole system.

I currently have 11" power booster and standard looking MC and prop valve with 3/16" lines to the front and 1/4" line to the rear along the frame.

I'm liking the Wilwood master cylinder and proportioning valve and I want to bend and flare my own NICOPP lines so here's the question: am I going to be OK with running 3/16" line to the rear?

I talked to a vendor and he said it's no problem. I think I read that somebody here has done that type of setup so what about it - does this seem like a reasonable way to go?

Thanks for any advice.

I just redid all the tubes and the hose to the rear drums on mine. Mine are manual. I used 3/16" copper nickel line for everything. Easy to bend everything by hand and double flared very easy. Should I have used 1/4" tube? Maybe, probably, but I can say the truck brakes great now so I'm not concerned.

[71threequarterton]

Originally Posted by S_Gibson

I just redid all the tubes and the hose to the rear drums on mine. Mine are manual. I used 3/16" copper nickel line for everything. Easy to bend everything by hand and double flared very easy. Should I have used 1/4" tube? Maybe, probably, but I can say the truck brakes great now so I'm not concerned.

OK, thanks for the info. As far as the lines are concerned, I'm hearing a lot of good things about ease of workability and longevity of the NICOPP stuff.

The MC and prop valve by Wilwood, on the other hand, apparently only have the 3/16" outlets but I guess the good news is, if I go with just about anything besides Wilwood I'll be saving money

[HO455]

Hydraulic systems like brake systems are a master cylinder that moves a specific volume of fluid per stroke of the piston. The amount of pressure is determined by the amount of force applied to the piston. The pressure is applied equally throughout the inside of the tubing and slave cylinders (and any other components installed). So the size of the tubing doesn't affect the pressure of the system, as long as the piston can supply enough fluid per stroke. (Too long of tubing or too large will limit the pressure capacity of the system.) In a brake system like ours there are two pistons supplying two sets of tubing and two sets of slave cylinders. (Calipers are slave cylinders just configured differently). In a perfect system where both pistons are the same size, and the slaves are the same size, when you move the pistons (at the same time). The slaves will react exactly the same. Same amount of movement and same pressure at exactly the same time.
If you redesign one of the two systems and give it slightly larger tubing and repeat the test. The side with the larger tubing will have the same amount of movement, at the same pressure, but it will be slightly delay when compared to the other system.
Thus if this is our truck in stock condition when you step on the brakes the rear slaves will always be applied slightly after the front slaves are applied. Now you could get the same results from a properly engineered brake proportioning valve, but GM is cheap and the cost of a one size step up in tubing versus a properly engineered proportioning valve was a no brainier for them back in the day.
For your application you can run the same size tubing for the rear as the front but you may want to install a adjustable proportioning valve in the line to the rear brakes to slow the speed at which the rear brakes are applied. Now you may not find that you have an issue with how your brakes work without an adjustable proportioning valve. But the day may come when you're on a wet corner at speed and have to tap the brakes and suddenly find that your rears have locked up!
As always your results may vary.

[71threequarterton]

I appreciate the detailed explanation, HO455. The Wilwood proportioning valve is adjustable in the very way that you described I would need it, based on their product info. It sounds like I could run that MC and prop valve with 3/16" lines front and rear but I'd really need to find a safe wide open area to safely drive it and really dial in the system... so, I'm still on the fence about the whole thing but I'm really appreciating the replies from everybody.

[jocko]

if the wilwood mc and prop only have 3/16 line capability, then it is likely designed as a disk/disk mc and prop valve. Can you use it? Sure, but why spend that amount of $ on something designed for a 4 wheel disk high end camaro restomod? My thought/recommendation - Wilwood is overkill for your truck (please don't take that the wrong way) - I'd spend the $ on one of member PICKMUP's beautiful stock mc/distrib block/booster setups specific to your application. I have one waiting for my K20's rebuild. However, I did completely redo my 71 C20's brakes - disks, calipers, drums, pads, shoes, all lines, booster, mc, and distrib block - and it stopped on a dime. It was quite the transformation - and I got all the parts at Autozone and they weren't expensive as I turned in the cores there also. You can't go wrong with stock, when new and tuned, it's about as good as you'll ever need. Unless, of course, you're taking your C20 slalom racing.

EDIT: one more note - make sure you are buying C20 (not C10) hydraulic parts (MC, distrib block, etc) - they are different from C10, and plumbed differently from the MC to the block. For example - the front reservoir on a stock C20 MC is for the rear 1/4" line brakes - the opposite of a C10. Make sure to ref the shop manual. If you go full custom with a Wilwood setup, all bets are off, you can build however you like at that point. Just mentioning in case you go with the stock approach.

[71threequarterton]

Originally Posted by jocko

Wilwood is overkill for your truck (please don't take that the wrong way)

Not at all! - I'm here for ideas and advice - Was/is your C20 the 1.125 in. Bore MC w/ 11.00 in. Booster?

I like the look of the Wilwood stuff and I like that it's made in USA but I also like the idea of saving some money and just going with the stock replacements - I still want to bend and flare my own NICOPP lines though.

[jocko]

It was this one: https://www.oreillyauto.com/detail/b...=50-1007&pos=0
(Oreilly, not Autozone!)

I bought several lines for this 71 job from inline tube, but bent them myself on a different 66 C10 project. Even if you bend your own, it's sometimes worth buying at least the MC to distrib block lines simply they are so short and difficult to get just right/looking right. When I bent my own, I used the regular old oem steel line type (not stainless). THey were easy to bend, and I didn't really like the green tint of the new type. It was actually kinda hard to find regular steel lines...

Here's what the above part # looked like installed.

[71threequarterton]

Originally Posted by jocko

It was this one: https://www.oreillyauto.com/detail/b...=50-1007&pos=0
(Oreilly, not Autozone!)

Excellent - Thanks for the parts link.