Hydraulic Brake Assist System - Just Stop It!

1 If your Mustang had factory vacuum power assist braking, you will not need to break out the drill. For manual brake cars like ours, the two upper mounting holes and the hole directly beneath the master cylinder opening will need to be drilled out. The brake pedal support bracket will also need its threaded inserts removed.

2 While only originally used on the '69-'70 Mustang, the mounting pattern is the same. Thus, we opted to use this gasket between the assist unit and the firewall from National Parts Depot (NPD).

3 Fitting the assist unit to the firewall will help in determining what holes need to be drilled out/enlarged and what threaded inserts to remove. Hydratech provides the correct mounting hardware for the upper left retaining point, as some firewalls used a bolt and others had a stud and nut affair. We left our pedal support thread insert in place here and used the supplied chrome Allen head bolt.

4 The remaining four mounting points are secured with serrated flange nuts from the passenger compartment side of the firewall. Start all of the nuts and tighten evenly to prevent cocking the assist unit and creating a bind point. A swivel socket helps here on a car with full wiring/gauges, but on an in-progress car like ours, access was easy with a long extension.

5 Displacement wise, the modular engines are relatively small (the 4.6L is but 281ci), but due to their OHC design, they are "broad shouldered," thus the limited room to fit a power brake solution. As you can see here, the Hydratech assist unit clears with 3/8-inch of room--plenty with our urethane engine mounts.

6 Back under the dash, the Hydratech assist unit's pedal mounting eyelet is made from billet steel, and each one is designed for the application intended and not some universal mount. The assist unit pushrod has a pivot feature to it for slight misalignment correction as well. The new brake light switch, retaining pin, and plastic washer are from NPD.

7 One of the neat features of the Hydratech pedal mounting eyelet is the threaded adjustment ability. The threaded pushrod allows the pedal eyelet to be moved fore and aft to adjust overall pedal height. Initially, our pedal was higher than we liked when we first connected the pedal. A few turns of the adjuster and our pedal was a good half-inch lower and right where we wanted it.

8 A quick check of the brake light switch with our digital ohm meter confirmed it was working as it should, and only allowing continuity when the pedal was depressed.

9 We ordered the deluxe pedal trim and "disc brake" pedal pad from NPD to offer a nice upgrade over the basic rubber pad that came pre-mounted on our reproduction pedal arm. We do have the brake pedal pad that matches the accelerator pedal, but it's narrower than the '68 pedal. For now we like the idea of a wider brake pedal to step on, but might trim it down later to fit the matching pad.

10 On direct replacement Hydratech kits, the two high-pressure PTFE braided hoses are pre-made and just need to be threaded onto the appropriate fittings. For custom setups, Hydratech leaves the hoses a little long, and with one end unfinished, so they can be completed in the field. Here, we've loosely installed the assist unit's inlet and outlet high-pressure hoses for measuring. The top hose will go to the power steering pump and the bottom hose to the rack.

11 Included in the Hydratech kit is a selection of fittings appropriate to your build (rack-and-pinion, stock or aftermarket pump, and so on). For late-model power steering pumps and rack-and-pinion units, these O-ring–style fittings seal the ports and convert them to standard -6 AN ports.

12 On the modular engine power steering pump, the outlet port is at the bottom. Thread the fitting in and then tighten with a socket and ratchet.

13 Route the correct braided line to the pump and install (loosely) one of the supplied fittings that will allow the hose to clear all moving parts (a 90-degree elbow in our case), and then mark the hose with tape or a marker/paint pen where it needs to be trimmed to length.

14a The Heidts Superide II front suspension we used on our project features a late-model Mustang power steering rack, and Hydratech's O-ring fittings thread right in to convert the ports.

14b The lower port is the high-pressure inlet port and the upper port (closer to the steering shaft) is the low-pressure return port. We used a 45-degree elbow fitting for the rack's high-pressure hose.

15 Hose assembly isn't difficult, but care must be taken at each step. Begin by applying tape to the area where you will be making your cut. You can use a hacksaw, hose shears, or a high-speed cutoff wheel if you have one. We prefer the cutoff wheel.

16 each fitting is comprised of three components: the socket, the sleeve, and the nipple, shown from left to right. These fittings are reusable and clockable for routing, but it's recommended new sleeves be used if the hose is disassembled for any reason.

17 After the hose is cut to its new length, the socket is slid over the braided outer jacket as shown. Think of this step as the same as flaring a brake line and ensuring the tube nut is installed before the line is flared (I know, we've all done it).

18 Insert the sleeve so that the PTFE liner is seated inside the sleeve to the lip of the sleeve and the braided covering is over the sleeve body. You can usually start the sleeve by hand, but pressing the assembly against the workbench or a block of wood will fully seat the sleeve.

19 Use a tapered punch to push the PTFE liner into the barbs of the sleeve, seating the liner into the sleeve.

20 With the hose nipple retained in a vice, apply a small amount of lubricant to the nipple and push the PTFE hose onto the nipple until it seats/bottoms. Slide the socket back up the hose to the nipple and then tighten it with the appropriate wrench to seal the hose end. You want 1/32-inch or less gap between the nipple and socket (use your thumbnail as a guide). Use compressed air or solvent to flush the line of any cutting/assembly debris.

21 Reinstallation of the hoses may require minor clocking of the end fittings. You can simply use two wrenches to hold the socket while turning the nipple end; just don't exceed the 1/32-inch installed gap doing so. Hydratech offers these simple, yet, elegant, billet hose clamps to retain the two pressure lines, as we've done here.

22 The last hose to connect to the assist unit is the low-pressure return hose. Hydratech provides the correct style of hose and the necessary clamps. One end of the hose features a simulated hose nut with integral clamp and this end is attached to the assist unit's return port. The rubber cap on the return port can be used to plug the intake manifold vacuum port if you had factory power brakes.

23 Route the hose as necessary to your power steering pump's return line where it will be tee'd into via the brass hose tee shown here. The assist unit's return hose is to be connected to the base of the tee, as shown, and then the regular power steering return line will be connected to the remaining ports. This prevents back pressure that can cause issues with the assist unit. You also have the option of running this hose directly to your power steering reservoir by adding an additional hose fitting to the reservoir. Lastly, if you have a power steering cooler installed, be certain the return hose tee is installed after any such device.

24 Hydratech offers several master cylinder options for its systems, but in our case, with the assist unit clocked to clear the engine, a vertical mounting pattern meant we had to use the '96-'99 Mustang master cylinder. Bolting it up is a simple matter of sliding the studs in place and securing with the included lock nuts.

25 However, as nothing is ever that easy for us, we ran into our one and only installation issue. The master cylinder's bleeder screws were hitting our engine's cam cover, preventing the master cylinder from fully seating on the assist unit. Not good.

26 We found a solution to our issue with these port plug fittings from Brakequip. The fitting on the left is designed to block off high-pressure fluid ports. Brakequip sells male and female versions in both metric and standard sizes. You can buy direct at www.brakequip.com or via phone at (865) 251-9193 with a $25 minimum order (these plugs are 99 cents each) or you can find you nearest dealer via the website or phone to purchase locally. Brakequip has hundreds of cool hose and fitting parts for projects like ours, so check them out.

27 Simply remove the bleeder screws, thread in the port plugs, and tighten with an Allen wrench. What could be easier! Because of their matching 45-degree seat, there's no need for sealers, as the plug seats just like the bleeder screw does to seal off the port.

28 Back on the assist unit and with the two master cylinder retaining nuts tightened, our problem is solved. Due to the angle of the engine install, the front master cylinder port is still a little close, but we're not going to worry about it until the car is running. If it touches on engine torque we can cut/grind down the port boss a good 1/4-inch additional clearance.

29 We also ordered an adjustable proportioning valve from NPD to install in our rear brake line. We often mount these to the inner fender somewhere with long screws and spacers made from 3/8-inch tube, but we found a metric-threaded boss on the side of the master cylinder that made for a perfect mounting location. We used a couple of washers to space the unit away from the master cylinder reservoir.