Wilwood 4 piston

[Jimbabwe]

I'm running a CPP 1" bore master manually with a disc/drum setup using 12" drilled and slotted rotors on CPP modular spindles.
What are anyone's thought regarding not adding a brake booster (and power master), but instead adding 4 piston Wilwood calipers on the 12" rotors. (I can swap the brackets with the modular spindles).
Thoughts regarding how good the braking would be with manual 4 piston vs. power single piston.
I ask all the good questions, I know...
Thanks

[SHANE 73Z]

I would guess the first question is how do you want them to work and what is your opinion of the present arrangement?

The number of pistons in a caliper has absolutely nothing to do in regards to ultimate braking power. Piston area does. The Wilwood D52 4 pistons have slightly larger piston area than the stock calipers. This would indicate a slight improvement in stopping power but I do not know if you could even tell by the seat of the pants.

There are plenty of ways to improve over the stock braking, but you have to look at the system as a whole. If you went with the Wilwoods and were not pleased with the performance are you willing to look at the rest of the system & continue from there?

Hope this helps,
Shane

[bricalabro]

I prefer power brakes. If your adding all the nice hardware having power will make it much better. I used a hydro boost set up. Couple modifications with the pedals and firewall. Works perfect. I used power steering pump, master, and booster from late 80's Chevy 2500
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[Jimbabwe]

The stock single piston doesn't seem to brake well at all for living in a busy place. Even braking early and leaving a decent amount of space, there's always someone trying to squeeze in or coming out of nowhere. I'd hate to smack up my truck because of someone else's stupidity. Talking to a few guys the other day, they all seem to think adding a booster merely requires less pedal effort and does not improve the actual braking.
I'm running an I6 with the stock air cleaner and there doesn't appear to be any room for adding a booster, even with a shorter bracket like Captainfab makes, or no bracket at all. I also like the more sparse clean look of the firewall with only the master, or none at all if I were to use an under dash setup, which I'd rather not because it looks like more a pain than it's worth. I can't use a frame mounted version under the cab because the truck is bagged.
I was looking in my 67-72 factory assembly manual and there are two pages showing boosters mounted on the frame rails and they are referred to as "vacuum power cylinders". That made me think of this:
http://67-72chevytrucks.com/vboard/s...d.php?t=512373
Picture #8. Could be interesting to try.
The D52 calipers are only 2 piston. A marginal difference, I think. I was thinking of the Dynalite ones. I know when I swapped from stock single HD calipers to 4 piston PMs on my bike (a long time ago) the difference was drastic. Yes, it's only 400lbs, but still.

[bricalabro]

A booster will greatly improve breaking. It also has a lot to do with what you have in the rear. I'm running stock single piston calipers from 73 and up. I have a Cpp 2 1/2 drop spindle. I'm also usin factory location on the booster and it takes up less room than a factory vacuum booster. The larger calipers will help. What kind of brake pads are on the truck and what's going on in the back
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[Jimbabwe]

The back are the stock drums. The front are 12" drilled and slotted rotors from CPP on CPP's modular drop spindles with Porterbuilt dropmembers f&r. Even the hydroboost setup would have the master hitting the I6 air cleaner. I like that it looks totally stock and sparse under the hood, but I would also like to not rearend anyone. (well...except for that cute girl that gets on the bus on wednesdays)
I'm sure that, without a booster, a 4 piston caliper would improve the braking over a single piston as well, but I haven't noticed anyone running their truck that way to ask their opinion.

[bricalabro]

There's a lot of variables. Just the compound of the pads could cause a issue. Some pads work better when they heat up. Stock drums in the back should be good if everything is working properly. A frozen wheel cylinder or bad portioning valve might screw up the rear stopping power. Can u get the rears to lock up when u hit the brakes
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[Jimbabwe]

Exactly, Tim. Cool factor does not trump performance, safety, or reliability.

[bricalabro]

when your ready to make a upgrade keep me posted im about a hour from the city, if you want to come up and check out my truck to see some options. i like old trucks, i also like making them drive like newer ones

[Jimbabwe]

Originally Posted by bricalabro

when your ready to make a upgrade keep me posted im about a hour from the city, if you want to come up and check out my truck to see some options. i like old trucks, i also like making them drive like newer ones

Will do.

[SS Tim]

There was a reason Chevrolet made power disc brakes standard on all but the lighest trucks. It was also required with most heavier options on those models built without it. Boosters give a shorter stroke and more pressure to the master cylinder input thus higher pressure at the wheels. You would be much better off searching out an air cleaner adapter as was used in the boosted trucks than trying to reinvent the world. More pistons will not help much without a booster. The heavy truck hydrovac boosters are used in addition to the primary booster and not something you really want. However there are aftermarket below floor hot rod size units that might help your situation if they are properly sized. In the end a stock style setup should give you a reliable, functional system. As far as a cleaner, sparse firewall vs brake performance really????

[Jimbabwe]

I'm not sure what pads were put in the brakes because my truck was at a shop having all the PB stuff installed. I gave them everything, including the calipers. I had freshly painted new ones I swapped for my old cores at Autozone. I've got a non-adjustable prop valve (CPP) mounted in my framerail, and rubber lines to the front calipers. I can't tell you if the rears will lock up (and perhaps an adjustable prop valve might be better) because I only recently got the truck back from the shop after the suspension work was done and there are several half-a$$ed problems that need to be fixed (by me), so I haven't driven the truck more.

[SS Tim]

OK here is something, your truck is a 69 correct? Formerly drum/drum. Did you remove the combination valve from the brake system or just add the CCP prop valve? What master cylinder are you running? Might really consider adding a 71/72 prop valve in place of the combination valve along with a matching disc/drum master cylinder.
With a disc drum system the prop valve reduces pressure to the rear brakes to overcome the disc's higher pressure requirement. While a factory prop might not have the perfect balance for your truck it wil be in the ball park and give you the factory warning light function.

[Jimbabwe]

Yes, a '69. Previously drum/drum. Every single thing is new. All previous stock components were removed. I got the 1" bore master and accompanying prop valve from CPP, telling them I would run the truck manually for the time being. The drum assemblies are all new as well since I sawpped from 6 to 5 lug.