Frequently Asked Questions:

Q: What is a "hydraulic brake assist unit" ?

A: Commonly referred to as "hydrobooster or hydravac" over the years, a high performance hydraulic brake assist booster is a powerful alternative to a vacuum assist type booster. This type of brake assist unit uses the hydraulic pressure from the power steering system instead of engine vacuum to provide a (powerful) brake pedal assist. Just to name a few, there are a number of Original Equipment Manufactures that are using these types of brake units on their production vehicles:
-'96 and newer Cobras and many V8 Mustangs
-Most 2500 and 3500 Series HD Series GMC / Chevy Trucks
-Dodge Ram equipped with Cummins Turbo Diesel / HD Option 
-Ford 250 / 350 / 450 / SuperDuty Series Trucks
-All Hummers - including the H2

Q: Do I have to install a different master cylinder?

A: In all but a few applications, your existing master cylinder can be used, as long as it is in proper operating condition and an appropriate bore size. If your master cylinder is more than ten years old, or shows signs of aging and wear, we recommend a replacement master cylinder be installed. We offer the option to provide a brand new replacement master cylinder with the purchase of our systems if required. 

Q: Is this a reliable and safe system?

A: Yes! This system is used in many new production vehicles on a regular basis and therefore has undergone rigorous testing by OE manufacturers to insure proper operations. Even under the most extreme conditions, you will find smooth, linear braking actions, regardless of engine speed and available vacuum levels. In most cases, a well maintained hydraulic brake assist system of this sort is known to have an almost infinite lifespan, easily outlasting the average lifespan of a vacuum assist brake booster.

Q: Is this the same type of assist unit that some of the diesel equipped vehicles use?

A: While basically similar in layout and appearance, the assist units that we utilize today are much more advanced and refined than the older assist systems. Design refinements over the years have solved the many leakage issues, vague assist response characteristics, pedal rod separation troubles, and overall lack of refinement. Current production models simply feel like a very potent vacuum assist would, with reliability previously unseen in the earlier models. We select the OE production models we feel best suit the specific needs of your particular applications, and then configure them for performance usage in your vehicle.

Q: Are these upgrade brake assist systems "show quality"?

A: Yes! All of our systems are handcrafted to very high levels of visual quality. We are always evolving the products constantly, and now offer three different levels of preparation. You can view images of our current production options on our products page:

Q: What type of warranty do your products have?

A: Hydratech Braking Systems guarantees its products to be free of defects in materials and workmanship for a period of one year from date of purchase. The brake assist units start life as brand new Bosch produced OE heavy duty service replacement brake assist units. They are all extensively dyno tested and certified by Bosch at the time of manufacture. We have a ZERO comeback rate as a result of the exceptionally high quality of these brake assist units.  The only way to truly damage these types of brake units is through heavy contamination of the power steering fluid, such as through a power steering pump or steering gear failure (placing metal particulates into the hydraulic assist unit). We have observed heavy duty OE truck installations that have well over a half a million miles on the original hydraulic brake assist units when the power steering system has been serviced on a regular basis!   

Q: I am experiencing problems with my brakes, will your kit help?

A: YES! If you are having troubles with your vacuum assist, due to a high duration cam not building enough vacuum or turbo / supercharging, then yes - this kit will really put some very strong and reliable brakes "back into the picture". If you are upgrading from manual braking to one of our conversion systems, you will be pleased with the straightforward, simple to install design, along with a tremendous improvement in braking power. Most "low pedal" and "pulling under hard braking" complaints with performance cars stem from having worn master cylinders, air in the system, ailing flex hoses and calipers, excessive play in the wheel bearings, or worn steering / suspension components. The installation of this type of brake assist system will NOT remedy these types of problems.

Q: Can I install this type of system if my car does not have power steering?

A: YES! These types of hydraulic brake assist systems do require that a power steering pump is installed (to power up the brake unit), though can be configured to run without actual power steering in place. Please contact us for further information on this topic. Here is a link illustrating just such an installation:



Q: How much additional engine clearance is this going to provide over a typical vacuum brake booster?

A: Overall, approximately 4 inches more spacing for tall valve covers is available by comparison to the average vacuum brake booster. The space savings will vary from vehicle to vehicle. When used on a C3 Corvette, possibly the worst offender of all, it is now possible to run a tall deck big block Chevy with tall valve covers while still retaining a power brake system, and still have room. The brake assist unit is just as slender as the master cylinder is on the engine side!

Q: I have 4 wheel drum brakes. Can I use this system on my vehicle?

A: We do not recommend the use of this system on cars with front drum brakes. We have found that excessive grabbing, and left to right front brake pull occurs with the use of this system. If you have installed a front disc brake conversion kit, this kit can be installed without the aforementioned problems.

Q: What type of fluid should I use with my power steering system. I have been told the automatic transmission fluid (ATF
) can be used?

A: We highly recommend the use of Redline, Royal Purple, or Lubegard power steering fluids. After 25 years of working with hydroboost systems, we know what works best based upon endless testing and always working with our customers. Using a poor-quality PS fluid results in erratic system behavior, noisy operation, along with a reduced lifespan. Note that we clearly state in our instructions to NEVER use automatic transmission fluid (ATF) in your Hydratech installation. Why? ATF is not interchangeable with power steering fluid because ATF does not have the anti-wear protection or shear stability needed. Power steering fluid is specifically designed to work in a MUCH higher-pressure range. The typical automatic transmission will never see more than 350 PSI, while a power steering system may produce up to 1600 PSI of pressure. When transmission fluid is pressurized quickly to 1600 PSI, then the fluid quickly reverts back to normal air pressure as it moves through the system, ATF cannot handle it resulting in aeration and foaming - the enemy of high-pressure hydraulic systems. Transmission fluid also has a completely different additive package in it that is designed to provide just enough lubrication to the bushings and bearings, but has less overall lubricity as the clutches inside of a transmission need to be able to bite when engaged without slippage. ATF also has special detergents and seal conditioning additives that are not proper for use in a hydroboost unit. If the seals are excessively softened by ATF, they can be damaged very rapidly. Can you imagine draining and refilling your automatic transmission with power steering fluid? It would just about immediately start slipping as power steering fluid is, well, vastly slipperier, not allowing the clutch packs to apply without slippage. On the flip side, power steering pumps, steering gears of all types, and hydroboost brake assist units operate under extreme load and pressure conditions, requiring a fluid that provides the maximum amount of extreme pressure additives - the more lubricity, the slipperier the fluid is, the better!

Q: I have been told that this kit helps with brake fade - does it really help?

A: Yes! In most cases vehicle braking improvements are vast, with "brake fade" becoming "a thing of the past". Be aware that you should stay mindful of the temperatures a high performance braking system can generate. If it is understood that brake fade is the relation between thermal efficiency vs coefficient of friction, (to cause a reduction in overall braking when hot requiring more pedal pressure to achieve the same amount of braking), then one could easily see where higher available line pressures help to raise the thresh hold of "real world" brake fade. Two major contributors leading to brake fade are boiling of the fluid and actual rotor / pad temp overheat. Hence the recommendation of upgrading to a brake fluid with a higher boiling point and air cooling ducting for maximum braking efficiency when running our systems on a road course.

Q: Can I bleed my brakes without the engine running, or before I connect the PS lines?

A: Yes - it is actually recommended that the brakes be bled with the engine off, which simply provides a "manual mode" of operations - no harm is done to the brake booster using this method. The components inside the brake booster simply "stack up internally" to provide a full manual brake actuation. You will find that the brake pedal height will be about 2 inches lower when the engine isn't running, or without the lines connected, as compared to a "powered up" pedal height. If brake bleeding is performed before the booster pressure lines are connected, some minor power steering fluid discharge may occur from the ports, which is completely normal. Since the hydraulic brake assist units provide a full manual mode of brake operations when powered down, the lack of a firm brake pedal during brake bleeding procedures clearly
indicates that air is still trapped in the lines, and / or possibly an indicator of ailing brake components elsewhere in the vehicles braking system requiring service. If the vehicle is equipped with rear drum brakes, or integral emergency brake type calipers, please insure that these components are in a proper state of adjustment, as this will greatly impact brake pedal height and operations in service.

Q: What is the nitrogen reserve / accumulator cylinder and what are its benefits?

A: The bottle on the side of most hydraulic brake assist units is referred to as an accumulator or nitrogen reserve. This stores up hydraulic power steering pressure in the event of an engine stall condition, to provide reserve brake assist power for up to 3 applications of the brake, similar to how a vacuum booster would function in an engine stall condition. Upon the first
application of the brakes after an engine stall, you would find approximately 60 - 75% of the normal assist available, then if you were to release and apply the brakes again, you would find approximately 30 - 40% assist, then again approximately 10 - 20%, until you have depleted all stored reserve assist. Once you have depleted all of the stored pressure, the brakes will no longer have power assist and will be manual in their operations. The minute you start the vehicle back up again, the accumulator gets filled back up with pressurized ps fluid again and is ready to go!

Q: How does this system connect to my power steering?

A: During installation you would remove your existing high pressure ps line, from the ps pump to the steering box or ps control valve. You would then install a replacement ps line from the pump to the assist unit, then another line from the assist unit to the original steering connection. This system, as installed, "piggybacks" the ps system, using the ps pressures, on demand only, to provide brake assist, without a disruption of normal ps operations. When not providing brake assist, it is just part of the flow circuit between the ps pump and the steering box / ps control valve assembly.

Q: Why are these kits listed as "for offroad use only"?

A: This statement is essentially what the "entire aftermarket / hotrod industry" bases its products on. We cannot possibly certify each and every one of these kits for "use on a public highway" as this would require extensive, expensive and prolonged testing as administered by the D.O.T. This, combined with the outrageous liabilities of "certification for street use", would more than quadruple the costs of the systems, along with delaying their availability for years, pending D.O.T. certification. We advise that you acknowledge this well known fact and use this product in accordance with these guidelines.

Q: Why have the Level II / Remanufactured systems been discontinued?

A: The lack of proper rebuildable "cores" is the primary reason for the discontinuance of this product line. The overall majority of sales over the years has also reflected a strong preference for the brand new assist units. We are also no longer providing remanufactured assist units for OEM replacement applications, and will now be providing strictly BRAND NEW replacements / upgrades for the earlier models.

Q: Why are these systems so seemingly expensive?

A: Only the finest materials are used in the composition of our retrofit kits. The adjustable brake pedal rod assemblies, specially made firewall adapters, high quality Aeroquip line set materials, and the assist units themselves, are all of the highest quality available. To lower the overall costs of the systems would reduce their visual appeal, attention to detail and craftsmanship, and the overall fitment and operations of the systems. A vacuum brake booster is definitely cheaper to produce, as it is basically 2 sections of stamped steel with a rubber diaphragm inside, as by comparison to a rugged, highly machined, hydraulic brake booster and braided stainless pressure line set.

Q: What applications do you have?

A: In most cases, this kit is a direct bolt in, and will fit many popular makes and models equipped with power steering - please view our online store in the products section, for full, detailed, listings. We are always working towards expanding our product line and are
developing kits for most popular vehicles. Please contact us with any special fitment needs or applications not listed.

Q: Is this a "true bolt in"?

A: Yes! In most cases, this kit can be installed without any permanent modifications to the vehicle in an afternoon's time, using common hand tools and skill levels. If you are not comfortable with performing the installation yourself, enlisting the services of a professional is highly recommended. Recommended professional labor rate should reflect an average of 4 hours billable labors for system installations.

Q: Is there anything else I should do to my car when I install this system?

A: Due to the higher line pressures that can be generated utilizing this system, it is highly recommended that a thorough inspection of ALL of the braking system components be performed carefully, replacing all marginal items, and brake flex hoses if they are more than ten years old. Additional gains in braking performance can be achieved by installing braided stainless steel, high performance brake flex hoses on all four corners.

Q: My car has manual brakes, can I use this system to add power brakes to my car?

A: Yes, If your car is equipped with power steering in 100% proper operating condition, this system can be easily and quickly installed. It may also be necessary in some applications to lengthen the brake lines going to the master cylinder, as any assist unit (even the installation of a factory vacuum booster) would put the master cylinder further away from the firewall. For example: Our C3 Corvette power brake upgrade system is by far the simplest and fastest method of upgrading to power brakes in this type of vehicle. This system can be cleanly installed in less than an afternoon's time, without having to modify the firewall or brake pedal in any way what so ever!

Q: Is this system going to cause a problem with my power steering system on my car?

A: This package ties into the hydraulics of your power steering system to operate. Therefore, this system will not function correctly if the power steering systems are worn and tired. Tired, leaking, weak, lazy, noisy, power steering components should be replaced to assure proper system functions. If your power steering systems are functioning correctly, all that is recommended is a thorough flush of the power steering system be done before you install the hydraulic brake assist unit. In some applications utilizing aftermarket or offroad steering systems, a high volume / high output pump and a cooler would be beneficial to the operations of the systems.

Q: Do I need to run a power steering cooler?

A: Though the power steering system lines may be hot to the touch during operations, in most cases a power steering cooler is not required. If you are experiencing fluid foaming after a hard run or if you are using the vehicle for road racing type events, where the vehicle is subject to higher than normal steering
system use, we would recommend the installation of a power steering cooler. Chevrolet Caprice police cars (9C1 Option code) were equipped with a factory cooler, these may be retrofitted to most vehicles. It is also possible to use a smaller high flow transmission cooler to reduce power steering system temperatures.

Q: Can this system be run on a mini power steering pump with remote reservoir?

A: In most cases the answer is yes, as we have many many satisfied customers successfully running the hydraulic brake assist systems using mini pump setups. It is however absolutely critical that the remote reservoir be of a well engineered design that aggressively promotes de-aeration of the power steering fluid. The mini pumps themselves are much more aggressive in their operations as a result of being substantially downsized. Because of this, foaming of the ps fluid is much more prevalent in these systems, and may require substantially extended periods of run time to fully de-aerate. Most "older style" full size ps pumps with integral reservoirs are far superior for use with hydraulic brake assist systems. Given a direct choice of running a Saginaw P series pump versus a mini pump setup, the venerable Saginaw P pump is the "hands down winner every time". In some cases there simply is not enough engine compartment space to run a traditional pump, requiring the use of a mini pump / remote reservoir setup. If space constraints dictate that a smaller pump must be fitted, we prefer the usage of a Saginaw P "traditional" type pump, using the later model GM truck remote reservoir style sheet metal housing (as shown here) in conjunction with a well designed remote reservoir.