Dual 8 inch booster installed

[My427stang]

Went with a "Pirate Jack" dual 8 inch booster with a Vette disc/disc master off Ebay. Really like it, a lot more reserve with the big cam, really stops the truck when you get on the binders. The truck was getting a bit fast for its brakes

[colnago]

Just out of curiosity, do you have discs in the back? Why did you go with a disc/disc MC?

Joseph

[My427stang]

So this master supposedly has residual valves that will work with disc/disc or drum/drum. I don't have a gauge on the lines, but with my drum/drum they aren't dragging. The kit was advertised as drum/drum, so my hunch is that whatever residual pressure they have works good enough to allow the springs to let them release.

If I had discs up front, my guess is I would have to limit pressure to the rear

[ultraranger]

Residual pressure valves would only be in a MC that's being used with drum brakes. Keeping pressure on discs would make them drag and get hot.

That style MC is a reproduction of the MC used on the Corvettes in the mid-'70s (designed for 4-wheel discs). If it's true to the original MCs, it shouldn't have any RPVs in it.

[My427stang]

That's not entirely true, although a disc can live without residual pressure, they often have a very light valve. Although I agree, it doesn't apply to mine.

http://www.mbmbrakeboosters.com/index.p ... &Itemid=16

However, I believe you are correct about this m/c I didn't probe around inside for a rubber flap. That being said, with the master being up so much higher, and the self adjusters keeping things in place, I have no issues at all. In fact, the braking is better than it has been ever, aside maybe from when the truck was a stock 302 2WD, and that is only because the big cam takes away some at idle. Although this dual 8 is FAR better than the stock single 8.75

I'd love to put discs on the front though, not an easy task for these trunion bearing open-knuckle D44s and I don't want a wider later model ball joint front end. Supposedly small Bronco conversions will work, maybe next year. or maybe narrow a newer D44. We'll see which is the smarter move next round, for now I am stopping pretty well, but the truck won't get slower over the next year

[ultraranger]

You're referencing aftermarket stuff. I'm really talking about the brake system as it applies to what would have been OEM or, if putting together a brake setup using OEM Ford brake components from another vehicle.

The only time you would need an RPV is if you had an old car/truck/street rod where the MC is mounted under the floor board. If the MC is mounted on the firewall (well above the level of the brakes), drain back from the brakes into the MC isn't a problem.

My truck orginally had manual 4-wheel drums. Currently (since October, 2014), I have '77 F100 2WD front discs/suspension and the stock rear drums for now. I got rid of the original style cast iron MC and installed a 'modern' '95 Explorer MC. it's designed for 4-wheel discs. It has no RPVs in it and I have no problems with the rear drums by not having an RPV in the brake circuit.

Wouldn't the disc brake front suspension from a '76-'79 F100/F150 4WD be a direct swap into your 4x4?