Mark Houlahan
Tech Editor, Mustang Monthly
March 14, 2014

There's something magical about owning a convertible, and it only gets better if that convertible is a vintage Mustang to boot! From annual parades to home coming games and the occasional wedding or two, vintage Mustangs are constantly called upon for their classic lines to transport dignitaries, home coming queens, and brides. Let's face it, what better car for the job right?

Driving down the road, top down so the wind blows through your hair, with your favorite song blaring from the dash speaker—its driving enthusiast nirvana and you are the coolest person on the road. That is until you have to raise your manual top to secure your Mustang or if you run into inclement weather. Then you look like a contortionist grappling with the top stack and trying to raise it without any help. You need to convert your convertible to power operation to raise your top at the flick of a dash switch!

Thankfully, most convertible Mustangs can easily be upgraded with reproduction hardware that simply bolts in to convert their manual tops to power. The top stack, top material, back window, and well liner do not need to be touched. All of these items, as long as they are in good working order now, will easily work with the parts you need to convert to power top operation. By adding the power top pump/motor assembly, the hydraulic rams with hoses, and the proper wiring and dash switch you can easily convert your manual top to power in one day. The only cutting required is for the dash switch (on '65-'66 Mustangs). Follow along as we take this '66 Mustang from “grab and groan” to “hit the switch and smile” using all new power top parts from Virginia Classic Mustang.

1. The majority of your work is going to happen behind the rear seat upholstery and quarter trim. The seat bottom cushion simply lifts out with a good tug to free the cushion from the floor retaining brackets on each side.
2. With the seat bottom cushion out of the way you will find two self-tapping bolts that retain the seatback cushion (one on each side). Remove these and then lift the seatback cushion straight up and off of the seatback retaining hooks at the top. Having the top lowered for these steps makes it easier.
3. The quarter trim panels are the last items to extricate to reach your work areas. You’ll have to remove the window crank (Allen set screw), several Phillips head trim screws, the windlace at the front of the panel—and most likely the door sill plates—to free the panel.
4. Once the quarter trim panels are out of the way you’ll spot what looks like a hydraulic top ram, but in actuality it is nothing more than a top frame counter-balance spring encased in a hollow metal sleeve. The new hydraulic components will replace these manual “helper” springs.
5. If you haven’t already removed the driver’s door sill plate go ahead and do so now, along with the driver’s kick panel. You’ll need these items removed in order to route the convertible top wiring between the dash switch and the motor.
6. When adding a factory-spec option like a power top, power steering, or other such item we like to refer to the original assembly line drawings found in the “Osborn” assembly manuals. These reprints of the factory drawings show proper wire routings, bracket and clip locations, and more for a successful installation that looks factory. For a power top conversion you’ll need the body and electrical books to cover the various assemblies.
7. Beginning with the top wiring we’re using the driver’s side motor wiring harness, which routes from the motor down under the left rear quarter window and forward through the door sill area. Ford used both left and right side power top harnesses, which are both available in reproduction. We opted for the left side harness for simplicity of installation/routing. Disconnect the car’s battery before starting any of the wiring steps.
8. The harness continues forward to the cowl side panel area where it is routed up past the door hinges and exits at the top opening. The two plugs at the end of the harness include one for the top switch (three wire) and a single connection to the under hood harness.
9. Under the hood a circuit breaker or fusible link is installed to protect the power top circuit (depending upon year of the Mustang). For a ’66 Ford used a fusible link with an insulated stud. If you look carefully you’ll find dimple marks in the battery apron for mounting the stud. Power comes from the starter solenoid’s battery stud through the fusible link. The under hood harness is connected to the insulated stud and the wire is routed along the passenger fender and shock tower brace (using clips) to the firewall.
10. At the firewall another drill dimple will be found just to the left of the neutral safety/back up light harness and above the eight-wire connector for the engine wiring. We used a step-drill bit on a 12-inch quick-connect bit extension to carefully drill out the dimple. Pass the under hood harness through the hole and seat the molded grommet into place.
11. Using the chrome dash bezel a thin cardboard template was created to locate the retaining pin holes and the central hole needed for the top switch shaft. The cardboard template was then transferred to the dash area for marking our locations to drill. Painter’s tape protects the painted dash as the three specific holes are drilled to match the template.
12. The top switch assembly is connected to the motor harness and the under hood harness and secured to the dash with the chrome bezel and its retaining hardware. The finishing touch is the switch knob, which is secured by an Allen head set screw. Installing the switch can be made easier by removing the gauge cluster, but we opted to work from under the dash to minimize scratching the dash or steering column on this 80,000 mile original.

What we ordered

'65-'66 Power Top Switch Under Hood Feed WG-105 $13.95
'65-'66 Power Top Switch to Motor Feed-Left Side WG-106 $37.95
'65-'70 Convertible Top Hydraulic Cylinder (x2) ST-164 $139.95
'65-'73 Convertible Top Motor ST-1647 $199.95
'65-'66 Convertible Top Motor Mounting Bracket ST-16471 $26.95
'65-'68 Convertible Top Hose Set ST-167 $89.95
'65-'66 Right Shock Tower Wiring Clips PE-4801 $4.00
'65-'66 Convertible Top Switch ST-157 $41.95
'65-'66 Convertible Top Bezel and Knob ST-1591 $32.95
'65-'68 Convertible Top Junction Block w/ Fuse Link ST-156 $19.95
Total $747.50

13. Moving on to the hydraulics the counter balance springs need removal next. The springs are at their lowest tension with the top up, so raise the top if it is currently down (no need to latch it) and remove the two bolts (per side) retaining the counter balance spring pivot bracket through the angled access hole in the well frame. You can see this hole in captions 4 and 7.
14. Reach up into the well frame and remove the pivot bracket. Keep the bracket handy, as it will be reused for the hydraulic ram installation. Reach up into the frame a second time and grab the counter balance spring and pull it free from the outboard pivot point. Lastly, remove the retaining pin and washers from the spring’s connection to the top frame to free the counter balance spring assembly, and then repeat for the opposite side.
15. The key to the power top’s conversion are these hydraulic cylinders mounted in place of the counter balance springs. Using hydraulic pressure the rams are either extended or retracted to move the top into an open or closed position. Shown here are Virginia Classic Mustang’s U.S. made versions. They’ll run you about $50 more per side but use higher quality internals and are exact replacements, not universal, and feature a 3-year warranty.
16. A hydraulic system like the Mustang’s power top requires hydraulic lines with specific fittings. The easiest solution is to pick up a set of Virginia Classic Mustang’s direct-fit line kits. The lines include the proper fittings and length and drop right into place. The short line is used for the upper cylinder fitting, shown here, and should be secured before the ram is installed.
17. Install the new hydraulic rams into place on the pivot pins and reinstall the pivot bracket and retaining bolts to secure the assembly. Be careful to ensure the ram’s top shaft is properly positioned in the top stack assembly (you might need an assistant to lift the top up slightly to seat everything). Once the rams are installed you can route and connect the longer fluid line to the bottom port on the rams.
18. You certainly won’t need the manual top’s hold down brackets anymore. These hold downs engage the end of the top stack to hold it in place when the top is down, but the hydraulic components will keep enough pressure on the stack to prevent movement/rattles. Simply remove the two retaining bolts (per bracket) and place them in your spare parts pile.
19. Virginia Classic Mustang carries top motors from All Classic Parts (ACP) in California. ACP’s top motors are known for their quality and fit and come with the correct wiring connections and mounting ears. Connect the hydraulic lines to the pump; the lower hose attaches to the front of the pump and the upper attaches to the rear of the pump (with the pump’s wiring pointing to the driver’s side).
20. Fill the top motor with ATF per the included instruction sheet, leaving the reservoir about 25 percent empty to allow for fluid movement while bleeding the system. Have a helper manually raise the top and then reconnect the battery. Your helper will then need to move the top switch up and down, a few seconds in each direction, to start pumping fluid through the lines.
21. After filling and pumping the system a few times you’ll start to see the hydraulic rams move in and out. Run them out to their full extension but no further. There are no internal stops and you could push the rams apart with pump pressure. Now bring the rams all the way in until they seat. Repeat this process a few more times until the fluid lines show no air and the reservoir is at the proper level.
22. Run the hydraulic rams out far enough to attach them to the top frame using new retaining pins and bushings (the counter balance spring hardware is different, so be sure to order the new bushings and pins with your hydraulic parts). Test the system one more time, now opening and closing the convertible top itself.
23. Once the system is bled, the top is connected and functioning properly, and there are no leaks you can mount the pump. Your Mustang should have these threaded nut inserts already in place. If not they are available from Virginia Classic Mustang.
24. The one elusive piece to the ’65-’66 Mustang power top conversion has been the power top motor mounting bracket. It is now finally available in reproduction and we were lucky to get one of the first ones from Virginia Classic Mustang. This bracket bolts down in the well area to provide a mounting point for the electric pump.
25. The four mounting points of the motor include two rubber push-in feet and two rubber isolators secured by nuts and washers. Lubricate the push-in feet and then place the motor into the bracket and give the motor a push/wiggle motion to seat the feet into the bracket. Finish the installation of the motor by securing the front mounting with the proper nuts and washers.
26. Secure the hydraulic lines using clamps adjacent to the motor opening in the well frame. We added a few sections of tape just like the Osborn manuals show to prevent chafing over the edges of the well frame as well. Reinstall your seat and quarter trim, door sill plates, and kick panel and you’ll be ready for your next outing to drop the top in style.