A few months ago @RFB started a thread asking about the possibility of converting a gas powered 80 from the factory vacuum brake booster to a hydraulic booster that is powered with pressurized power steering fluid. A kit from a company called Power Brake Service was referred to specifically.
I liked the idea although this conversion on an 80 had never crossed my mind. The rig I built prior to purchasing my first 80 in 2014 was fitted with a hydro booster and one ton axles which produced absolutely phenomenal braking power with 40’s and 3 tons to stop.
Since I was nearing the day I would delete the ABS system from my rig, and my prior experience with hydro boost was very good, I ordered a kit from Power Brake Service.
The kit that I received was not sitting on the shelf. Matt, at Power Brake Service had to put it together from scratch and it took 16 days to ship. The parts were packaged well and everything I needed was included and fit properly.
Along with the hydro booster, I chose a Wilwood MC with a 1.125” bore. The oem MC has a 1” bore and will not bolt up to the GM hydro booster. A bigger bore equals a shorter pedal stroke.
The pressure hoses are steel braided and route fluid power from the PS pump to the booster and then to the steering box. At the booster, banjo fittings were used and field installable JIS style fittings with metric to SAE adapter unions were used at the steering box and PS pump.
The manual proportioning valve is a Wilwood Combo proportioning valve that has two “in” ports and 3 out. There are separate pressure ports for the front calipers so a tee is not needed. This kit is put together in an ala carte manner so the MC and proportioning valve were my choice as well as the steel braided pressure hoses.
It didn’t take long to figure out that the booster would have to be installed upside down on account of the accumulator cylinder and the engine upper plenum competing for space. This is not a problem but does require more time to bleed the air from the booster because of the return line now being located on the lower instead of upper side of the booster. The upside down mounting also causes the pressure hoses to be routed down low which, IMO, makes for a cleaner install. The return hose from the booster is routed to a point where it tee’s into the system return hose about a foot or so below the reservoir.
As part of this project, I disassembled my PS reservoir and cleaned the strainer. In order to keep from ever needing do this again, I installed a Magnefine in-line fluid filter between the Tee of the booster return hose and the reservoir.
Where the factory hard brake lines were longer than necessary, I chose to make two new lines using a soft copper/nickel type of brake line that is very easy to work with, DOT approved, corrosion resistant and rated up to 4600 psi. All bends were made without a bender.
List of stuff:
-Napa Eclipse calipers
-Hawk Super Duty ferro carbon front pads
-StopTech 309 rear pads
-DOT 4 synthetic brake fluid
-25’ Copper/Nickel brake line kit from eBay that came with a generous assortment of fittings. Around $25
-Rigid brake line cutting and flaring kit #33927 $115. (Very good tool kit for the price. I chose it because I couldn’t find one negative review.)
-Magnefine fluid filter $25
-steel braided hoses for axle to caliper locations. $140.
-Complete hydro boost kit with addition of the Wilwood Combo proportioning valve $1100. I chose a brand new booster instead of rebuilt, steel braided lines were extra, I could have chosen a cheaper MC and the proportioning valve is completely optional.
Since the plumbing is now simplified, bleeding the lines is as simple as cracking the caliper bleed ports and letting gravity do the job. This was impossible before.
The booster kit comes with a set of very complete, easy to understand instructions and install was a simple straight forward affair. Making the hard lines was probably the most challenging part of the entire job. Bleeding the PS system was done exactly as outlined in the factory service manual but did require a good bit of patience which I attribute to the booster being installed upside down.
Reasons for doing this:
-after removing my abs system, the results were not what I had hoped for. (Results vary and are subjective)
-I had no knowledge of the age and condition of my vacuum booster and MC so preventive maintenance was a factor.
- brake line pressure created by a hydro booster is roughly twice that of a typical vacuum booster, so, theoretically, this would give me greater braking power hence shorter stopping distances. Greater booster power allows the use of a larger bore MC which moves more fluid per millimeter of stroke.
- my previous experience with hydro boosted brakes is positive.
- proven reliable
The end result is a high, firm pedal that delivers smooth, linear stopping power far greater than what I had before. Only the weight of my foot and leg resting on the brake pedal is necessary to remain stopped at traffic lights. I haven’t taken measurements to see exactly how many feet it takes to stop from a certain speed but I can say that my expectations have been exceeded as I was a bit skeptical due to the fact that my rotors and calipers are stock equipment. Choice of brake friction material may have considerable bearing on the final outcome.
I liked the idea although this conversion on an 80 had never crossed my mind. The rig I built prior to purchasing my first 80 in 2014 was fitted with a hydro booster and one ton axles which produced absolutely phenomenal braking power with 40’s and 3 tons to stop.
Since I was nearing the day I would delete the ABS system from my rig, and my prior experience with hydro boost was very good, I ordered a kit from Power Brake Service.
The kit that I received was not sitting on the shelf. Matt, at Power Brake Service had to put it together from scratch and it took 16 days to ship. The parts were packaged well and everything I needed was included and fit properly.
Along with the hydro booster, I chose a Wilwood MC with a 1.125” bore. The oem MC has a 1” bore and will not bolt up to the GM hydro booster. A bigger bore equals a shorter pedal stroke.
The pressure hoses are steel braided and route fluid power from the PS pump to the booster and then to the steering box. At the booster, banjo fittings were used and field installable JIS style fittings with metric to SAE adapter unions were used at the steering box and PS pump.
The manual proportioning valve is a Wilwood Combo proportioning valve that has two “in” ports and 3 out. There are separate pressure ports for the front calipers so a tee is not needed. This kit is put together in an ala carte manner so the MC and proportioning valve were my choice as well as the steel braided pressure hoses.
It didn’t take long to figure out that the booster would have to be installed upside down on account of the accumulator cylinder and the engine upper plenum competing for space. This is not a problem but does require more time to bleed the air from the booster because of the return line now being located on the lower instead of upper side of the booster. The upside down mounting also causes the pressure hoses to be routed down low which, IMO, makes for a cleaner install. The return hose from the booster is routed to a point where it tee’s into the system return hose about a foot or so below the reservoir.
As part of this project, I disassembled my PS reservoir and cleaned the strainer. In order to keep from ever needing do this again, I installed a Magnefine in-line fluid filter between the Tee of the booster return hose and the reservoir.
Where the factory hard brake lines were longer than necessary, I chose to make two new lines using a soft copper/nickel type of brake line that is very easy to work with, DOT approved, corrosion resistant and rated up to 4600 psi. All bends were made without a bender.
List of stuff:
-Napa Eclipse calipers
-Hawk Super Duty ferro carbon front pads
-StopTech 309 rear pads
-DOT 4 synthetic brake fluid
-25’ Copper/Nickel brake line kit from eBay that came with a generous assortment of fittings. Around $25
-Rigid brake line cutting and flaring kit #33927 $115. (Very good tool kit for the price. I chose it because I couldn’t find one negative review.)
-Magnefine fluid filter $25
-steel braided hoses for axle to caliper locations. $140.
-Complete hydro boost kit with addition of the Wilwood Combo proportioning valve $1100. I chose a brand new booster instead of rebuilt, steel braided lines were extra, I could have chosen a cheaper MC and the proportioning valve is completely optional.
Since the plumbing is now simplified, bleeding the lines is as simple as cracking the caliper bleed ports and letting gravity do the job. This was impossible before.
The booster kit comes with a set of very complete, easy to understand instructions and install was a simple straight forward affair. Making the hard lines was probably the most challenging part of the entire job. Bleeding the PS system was done exactly as outlined in the factory service manual but did require a good bit of patience which I attribute to the booster being installed upside down.
Reasons for doing this:
-after removing my abs system, the results were not what I had hoped for. (Results vary and are subjective)
-I had no knowledge of the age and condition of my vacuum booster and MC so preventive maintenance was a factor.
- brake line pressure created by a hydro booster is roughly twice that of a typical vacuum booster, so, theoretically, this would give me greater braking power hence shorter stopping distances. Greater booster power allows the use of a larger bore MC which moves more fluid per millimeter of stroke.
- my previous experience with hydro boosted brakes is positive.
- proven reliable
The end result is a high, firm pedal that delivers smooth, linear stopping power far greater than what I had before. Only the weight of my foot and leg resting on the brake pedal is necessary to remain stopped at traffic lights. I haven’t taken measurements to see exactly how many feet it takes to stop from a certain speed but I can say that my expectations have been exceeded as I was a bit skeptical due to the fact that my rotors and calipers are stock equipment. Choice of brake friction material may have considerable bearing on the final outcome.
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