We are nearing completion of our 1953 Buick Roadmaster Riviera 2-door hardtop 76R.  It has been a long process of restoring the complete car and we are now in the last stages of installing interior, chrome, trunk liner and detailing (See www.southernwheels.com and click Archives)  Everything was done to OEM specs, including retaining the original Hydro-Lectric power windows and seats.  

        Although there had been some development in the 30s using Hydro-Lectric applications, Packard was the first car to use it in production in its top of the line 180 Custom Super 8series with power windows, then Ford in its Lincoln Custom Limousines and 7-passenger cars .  In 1941, Cadillac also used it in its 75 Series Limousine, but only for the divider windows.

        GM used it briefly in 1942 on its convertibles, but the use of the system really didnt become industry wide until after WWII.  The system had been used and refined during the war in the development of military weapons.  Here is a list of the postwar cars it was used in:  

        Buick 1946-53 (was continued on the 1954 Buick 66C)

        Cadillac 1946-53

        Chrysler 1946-51, Hudson 1948-55

        Lincoln 1949-51

        Mercury 1949-51

        Oldsmobile 1946-53

        Packard 1948-55

        In 1953, GM changed from 6V to 12V systems and in 1954 GM dropped the system altogether in favor of all-electric windows, seats and tops.  There were two types of systems:  Dura and Moraine.  In this article, I will cover Moraine, the type used on our 53 Buick, which is a 12V negative ground vented system.

        For easy identification, there is an ID plate on the motor and Moraineengraved in the canister.  I have covered the removal, repair and installation of this and it can be read in our Archives online.  The purpose of this article is to cover How the System Operates, and a Troubleshooting Guide.  It has been 5 years since the windows have moved.  After we rebuilt and tested the system, it checked out okay, so we moved on to painting and other phases of the restoration.  Recently, when we checked the fluid level and turned the key on, we heard a clickindicating power to the motor.  It was a pleasure when I operated the switches and watched the windows go up and down.  All that is left to do now is to install the front seat track.  The seat cylinder unit works, but the seat track is stuck!  Always something!

 What is the Hydro-Lectric System?

It includes two systems:  1) Electrical to control window, seat and top and drive the pump, and 2) Hydraulic system to supply fluid under pressure to each cylinder.

        The 1953 Buick's Moraine Hydro-lectric pump unit is mounted on the right side of the cowl at the rear of the right front fenders inner fender well.  It is cushioned on rubber mountings and is connected to the hydraulic steel lines (pipes) by rubber hoses.  The motor is grounded to the body via a ground strap.  The 53 Buick has a 12 volt, negative ground electrical system.

         The power unit consists of  an electric motor, a rotor type oil pump and a metal canister for the fluid that supplies the windows, seats and convertible top.    Moraineand a mark to show the fill level is embossed into the canister.  GM originally used Dot 3 brake fluid which worked well until it sprang a leak.  Many cars of the day could be identified as Hydro-lectric cars by where the brake fluid had leaked out of the doors and stripped the paint off of the rocker panels.  Now, when rebuilding the system, automatic transmission fluid (ATF) is used.  We use Dexron, which was recommended to us by Hydro-E-Lectric*, when they supplied us with all-new hydraulic cylinders for our doors and seat.

         The pump unit works  when the solenoid relay switch closes the circuit between the battery and power unit motor when the solenoid is energized by current flowing through the closed control switch.  When a switch is activated, current passing through the solenoid windings to ground causes the solenoid plunger to move upward until a plunger contact closes the battery to motor circuit.  This starts the power unit motor so that the pump deliver fluid pressure.  When the control switch returns to its neutral position, the energizing circuit is broken, the solenoid is demagnetized and the plunger drops to break the battery to motor circuit, thus stopping the fluid flow.

         When adding fluid  to the canister, you must pull the snap spring wire (bail) to one side.  This allows the canister to drop.  Beware of the fluid!  Dont twist or pull downward on the canister or the gasket sealing the canister to the unit can be torn.  If this happens, another gasket can be cut from gasket material for fuel and oil.  The reservoir is vented into the atmosphere through a small hole in the pump body.  Care must be used when painting the pump body in restoration, not to plug up the vent hole.

         The pump housing contains  a drive and driver motor and a pressure relief valve.  The pressure relief valve is located at the exit port.  When the  pump is not running, the pressure relief valve spring holds the valve in position to close the rotor exit port and open a passage between the pressure line port and the reservoir.  When a window is lowered or the front seat is moved rearward, this is done by a large spring on the window or seat cylinder unit.  In other words, fluid moves windows up and the seat forward and a spring moves the window downward or the seat rearward.  The window and seat use the same styled switch and they are the same from 1949-1953.  They are being sold by Fusick* and sell for around $95.  The rear of the switch is marked MOT (motor), BATT (Battery) and CYL (cylinder).  The cylinder has a single connector wire with a blade end.  This blade plugs into a female plastic connector in the cars circuit that changes to an eyelet end, which connects to the brass lug on the switch.  When the switch is pushed to its Down position, the spring pulls the window down or the seat back, the fluid is forced out of the hydraulic power cylinder, and returns to the pump through the pressure line, flows through the valve spring and drains into the reservoir.  When the top, seat or window reaches the end of its travel, pump pressure builds up to a maximum of 260 psi, forcing the pressure relief valve farther outward until a stationary stop pushes the ball off its seat in the valve, providing an opening, letting the surplus oil return to the reservoir.  This prevents the maximum pressure from exceeding its limit of 260 psi.

 Door and Rear Quarter Hydraulic Lifts:

 The window lift units fit into the doors and rear quarters vertically, with the scissor mechanism at the top of the lift.  The lower end of the unit frame is attached to the door and the operating arms on the upper end engages a cam connected to the windows lower channel.  The cylinders piston rod pushes up on the operating arms to raise the window glass when fluid is sent into the cylinder.  When the window is lowered via the spring the valve in the cylinder is opened, allowing the fluid to escape.

 Hydraulic Seat Adjuster Regulator:

 The front seat is powered by a regulator with the same design as the windows, except slightly larger, and uses the same type control switch.  The switch is located on the front of the drivers seat side panel.  As previously mentioned, the seat is moved forward by fluid pressure and moved back by spring pressure.  To prevent forward movement of the seat in a panic stop, a ratchet mechanism is built into the frame assembly.

 Control Switches:

 The chrome toggle switch normally stays in the middle position (open position).  There is a main cluster switch mounted on the drivers door panel that operates each window.  This switch controls 1) Right Rear Quarter Window, 2) Left Rear Quarter Window, 3) Right Door Window, 4) Left Door Window.  There are single switches positioned on each of the above locations.

 Control Switch Positions:

 When the switch is released, it is in the center (neutral) position, so all electrical circuits are opened.  When the switch is in the  Up  position to raise a window or move the seat forward, the circuits to the power unit motor are closed, thus allowing fluid to enter the cylinders.  When the control switch is moved  Down  to lower the window or move the seat rearward, the circuit to the solenoid valve is closed, causing the valve to open.  When the solenoid valve opens, the pressure of the return spring forces fluid out of the cylinder back through the fluid lines and into the power units reservoir by way of its return line.  When the switch is in the Center (neutral) position, the fluid is trapped in the cylinders.  This is what causes the window to stay in position and the seat to remain stationary.

                                         Trouble Diagnosis:

 Before doing any diagnosing, always check for a fully-charged battery and clean and secure cables, and check the reservoir fluid level which should be 1/2below top with the windows down and the seat back.  CAUTION:  Keep dirt and water out of the system!

 Problem:                                                                                            Cause:

 Window lift inoperative                                                Window misaligned

Electrical short or

loose connection

Check switch and pump wiring

Test cylinder

Fluid low

Window operates slowly upward                                Electrical failure

                                                                                                                Low battery

                                                                                                                Stuck pump

                                                                                                                Check for dust of armature

                                                                                                                Partial stoppage or leaking fluid lines


Windows Operate Slowly Downward

If window moves downward
slowly with control switch in

Neutral, the solenoid

lift cylinder is leaking

Glass binding:  

Hydraulic fluid is old, congealed or too heavy for


                                                                                                Pump pressure relief valve is stuck

Window raises when top or seat is


Wires shorting

Cyl wire touching Batt wire                                                        

Hydraulic pressure too high if more than        one window raises

Two windows operate from                         Electrical control

one switch                                                                         circuit crossed due to

                                                                                                both windowsswitch CYL
                                                                                                terminals touching

                                                                                                Hydraulic pressure too high

Seat adjuster inoperative                                Mechanical interference

                                                                                                Seat track binding, mis-aligned,
                                                                                                object under seat,
                                                                                                cylinder unit not grounding

                                                                                                electrical fault (same as windows)

                                                                                                hydraulic fault (same as windows)

Seat operates slowly forward or                 Same as windows operating

rearward slowly

All units operate slowly in either                 Mechanical interference

direction                                                                                Low battery

                                                                                                Fluid too heavy for weather conditions

                                                                                                Stoppage in fluid lines

                                                                                                Pressure relief valve stuck

Power unit inoperative on any                        Low battery

ignition control                                                         Wire connectors between ignition switch and solenoid relay circuit

                                                                                                loose or disconnected the pump runs, the                

Circuit breaker inoperative

correct sound it produces                                Solenoid relay switch inoperative

is a whirringsound)                                                Power unit motor inoperative






        We will continue this article in an upcoming issue with repairing and installing the front seat and track, and finishing the system.  I will also include a list of manuals on these systems.  Keep em driving!