BroncoII4x4.com

My Bronco II brakes have always sucked. They stop fine, but the peddle was always soft. Since the stock master cylinder is only 15/16 bore, I was just going to swap it out with something bigger. I wanted something designed to work with rear disc anyway. I quickly found out that because of the vacuum booster design, none of the popular master cylinders would bolt up.

So, out with the old, and in with the new! I picked up an Astrovan hydroboost unit at the junkyard. It cost me a grand total of $6.50 + $3.50 core Since it's GM, the popular Corvette master will bolt right up. It's a 4 wheel disc master, and it has a 1-1/8 bore.

It looks like it's going to be pretty straight forward. I drilled out the bottom 2 holes in the firewall. The for the top 2 holes, I'll redrill the mounting plate on the hydroboost and use the stock holes in the firewall.

The brake peddle rod is too long and will need to be shortend. Otherwise, it almost bolts right up!

puuurdy!!! i thought you were doing this to the EB? either way nice job so you going to run the vette master? also what yr aerostar? i might just pick one up for future use.

The EB is getting hydroboost too. I didn't find anything great on my last trip to the junkyard, so to make the trip worth while I grabbed another hydroboost.

I don't know what years the astros are....I asume early 90's. It really doesn't matter though. Most of the hydroboost units are the same. They aren't real common in the junkyards though.

i need a rad so this friday im hoping to get up to the pick&pull in Fresno. hopefully i run down something. i'll keep my eye out for one of those bad boy's. the hydroboost is pretty trick my buddy ran it on a D50 Hybrid he built.

thats cool, I have been looking at that upgrade for the EB. don't realy want to convert to power when I could get that right from the start.

Hey Matt,

Care to elaborate on the "Hydroboost" a little for us intalektchually challenged? I'm guessing it doesn't work off of vacuum corect?

Hydroboost is a brake booster that runs off your Power Steering pump. No vacuum involved. It's like having super human strength in your legs. It's typically used in large cars, and diesel trucks.

The compact size of the hydroboost makes it popular for conversions on classic cars.

Vacuum boosters are really all you need, but as I mentioned, the stock Bronco II booster is designed in a way that makes it difficult to use a different master cylinder. The cool thing about hydroboost is it will work on the Moon!

Lots of info at www.hydroboost.com

Wow, that is awsome. That is definately a mod worth doing. Junkyard parts around here would be expensive though. Everyone who owns a yard thinks it's a gold mine. Law of supply and demand I guess.

Thanks for the info. That got added to the list of future updates.

The only junkyards that are affordable are the U-pull-it type. I have to drive almost an hour to get to one.

Nobody wrote:The only junkyards that are affordable are the U-pull-it type. I have to drive almost an hour to get to one.

Then move!
If you do head down Sat maybe we can make a quick side trip to the PaP.