We Boost Our Bronco’s Braking Power With Hydratech’s Hydroboost Conversion KitPosted in How To: Suspension Brakes on June 5, 2017
We spend a lot of time and money setting up our 4x4s with lift kits, bigger tires, winches, body armor, lights, engine and other mods, with the end goal our rigs are better equipped to handle our four-wheeling forays better than they could in stock trim. The payoff for all those efforts is our rigs look better, stand taller and run stronger, just like we’d planned. What we didn’t plan on was some of those modifications take a toll on braking, especially on older gas pickups and SUVs running vacuum-assisted brakes.
A bulkier vehicle, along with the increase in the heavier rotating mass of the tires/wheels and the change in weight transfer from a suspension lift, make it more difficult for the stock braking system to handle the job, resulting in poorer braking performance. Add a performance cam, as many of us do, and vacuum-assisted brake systems take an additional hit in braking at idle or off-throttle situations.
This degradation in overall braking performance is especially noticeable on Ford’s ’80-’96 F-150s and Broncos. Even on a good day, the vacuum-assisted brakes on these rigs feel weak and spongy when rolling to a stop or easing down a steep grade, which is common when off-roading.
Installing a cam with more lift and longer duration, as we did to our ’91 Bronco’s 5.0L, and the amount of vacuum the engine creates at idle is even less than it was stock, compounding the braking issues.
Braking Cure AllAll is not lost. The cure is simple: Convert from vacuum-assist to hydraulic-assist, or “hydroboost.” Hydroboost brakes use the pressure of the hydraulic fluid in the power steering system to apply more braking force in the master cylinder, creating far more stopping power than engine vacuum could ever attain.
A great benefit of hydroboost braking power is there’s no loss in performance at idle or off-throttle situations. This is great for wheelin’ because when you ease down on a steep incline the brake pedal remains firm and the brakes rock solid. Hydroboosted brakes are also far less prone to brake fade, a common occurrence in vacuum-assisted brakes when towing in the mountains.
Those were the very reasons we decided to upgrade to hydroboost brakes on our ’91 Bronco, Eddie. We’d thought about cobbling together a hydroboost brake system using parts sourced out of a ’90s Super Duty. Then we quickly realized the fabrication, pedal alignment, and general safety issues weren’t something we were comfortable dealing with on our family daily driver.
Hydratech ConversionAfter talking with Paul Clark at Hydratech Braking Systems, we opted instead to do our Ford’s brake upgrade the right way: using a hydroboost conversion kit engineered specifically for the F-series and Broncos. (Hydratech also offers a similar conversion kit for GM and Dodge trucks/SUVs running vacuum-assist brake systems.)
Hydratech uses a new OE Bosch production hydroboost unit and retrofits it with a CNC-machined T6061 billet aluminum adapter so it’s a direct bolt-in factory replacement for the big Ford vacuum booster can. The kit also includes a slick brake pedal rod and spin-on adapter that makes it easy to install and adjust brake pedal height. Hydratech also supplies two over-length Aeroquip TFE-series braided-stainless hoses and all the rebuildable/reusable AN-6 fittings to make the installation clean and tidy.
All that made it easy for Mobile Diesel Service’s Ruben Villalobos to swap out the stock vacuum-assist brake system in our truck to Hydratech’s hydroboost. It took him about two hours to make the swap, which also included replacing the old master cylinder with a new one just to make sure all was right when we hit the road.
Installed, Hydratech’s hydroboost looks far better than the big, ugly vacuum can hanging on the firewall. However, the clean look under the hood isn’t anything compared to the dramatic difference in how the brakes work and feel: the pedal is firm, the brakes aggressive. Throwing out the anchor, our big Bronco now is more like you’d expect to feel in a sports car than behind the wheel a 3-ton 4x4. The vacuum-braking woes are gone for good! We only wish the brake conversion had been addressed early on in our truck’s rebirth.