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



        In 1953, Hydro-Lectric was available at Buick in its 56R, 56C, 76R, 76C, 76S.  Our car is the 53 76R (2 door hardtop) with Hydro-Lectric power windows and front seat.  The windows, as covered in last months article, are fairly simple:  Fluid moves them up and a spring pulls them down as the fluid voids the cylinder and returns to the pump reservoir.  The seat mechanism is a little more complex.  The similarities are:  The seat has a single switch the same as the windows, and it works the same.  On the right back of the switch is marked MOT(motor) and has a tan/green tracer wire attached.  The center post is marked BAT(battery) with a tan/red tracer wire, and the left post is marked CYL(cylinder) with a tan/black wire.  All are 14 gauge wires.  Finding people who know anything about the seat tracks has been next to impossible.  Fortunately, I have most every GM manual that covers the Hydro-Lectric system.  At the end of this article, I will list and rate them.  Some have been very helpful.

         Our Cars Hydro-Lectric System:   When we got the car over ten years ago, the only thing that worked right on the power system was the pump.  The windows would go up but not down, and the seats wouldnt move at all.  All of the interior        had to be done anyway, so we removed everything from the interior and totally rebuilt the Hydro-Lectric system.  That was ten years ago, and everything still works with no leaks.  Now it was time to go through the seat tracks and get them to work with the Hydro-Lectric seat mechanism.

        The Hydro-Lectric seat unit consists of frame, cylinder, spring and switch.  The unit is positioned under the front seat on the drivers side and the unit attaches at the rear by a single bolt through the unit to the floor board.  This also grounds the unit (it wont work unless grounded).        It attaches in the front from the Hydro-Lectric unit to the seats pivoting Vbracket with one bolt.  The seat unit is the same as the window units, except the seat unit is slightly larger (uses same cylinder).  The seat is moved forward when the switch is pushed to the UP position, moving 260 PSI of fluid into the cylinder and will move a maximum of 500 pounds of weight in the seat from its furthest rearward to the furthest forward position in five seconds, then back to its furthest rearward position in three seconds.  When the seat moves backward, it does so by the large spring on the Hydro-Lectric mechanism and the voiding of the fluid back into the pumps reservoir.

        Of course, all parts of the front seat had to work, so we set up a 4x8 table and re-constructed the seats out of the car.

        GM's description of their 50 (Super) and 70 (Roadmaster) Series cars is:  These cars have Tilt-in Seats(split seat backs) mounted on a bench seat bottom.  The seat unit has a diagonal pivoting movement of the seat cushion to provide maximum ingress and egress for rear passengers.  When either front seat back is tilted forward (one at a time) as it tilts inward, it also acts as a lever to rotate the entire seat assembly about a pivot point on the opposite side.  This allows the seat to move forward beyond its furthest position on the Hydro-Lectric unit.

        Seat terms that GM used, which we will use in this article are:

        Seat adjusters:  are seat tracks

        Inertia Locks: are counter-weighted lock arms

        Actuating plates: a piece that attaches the outside hinge of the seat back to the seat track.

        The seat adjusters are designed to prevent diagonal or lateral movement when the seat backs are in normal position.  The seat adjusters (seat tracks) are equipped with inertial locks, which prevent free forward movement of the seat in case of a sudden stop, causing the seat back to be thrown forward.  A sudden stop causes a counter-weighted lock arm to swing forward around its hinge pin until the hooked end of the arm engages a lock pin, thus locking the seat in its Hydro-Lectric position.  This makes the seat to move forward and back by the Hydro-Lectric unit only.

         How to Check Operation of the Inertia Lock:   

        1. Make sure that inertial lock arm operates freely on its hinge pin.

        2. Operate the seat backs by folding inward (one at a time) to check for free operation of the seat adjusters (tracks) and actuating plate assemblies on the outside hinge arm of the seat backs.

        3. With seat backs in full rearward position so that the inertial locks are touching the rubber bumpers below them, raise the lock arm into contact with the lock pin above the lock arm.  A gap of 1/16should exist between the arm and the pin.

        4. If seat tracks and actuating plates on the seat back outer hinges are working correctly and not binding, but the lock arm does not have 1/16clearance in its lock position, filing or grinding the front edge of the lock pin can be done, so long as no more than 1/16" of stock is removed from the lock pin.  That is from the 1953 Buick Shop Manual Supplement to the 1952 Buick Manual.  The previously mentioned rubber bumper blocks were changed mid-year.  Here is the change posted in 1953 Buicks Product Sales Bulletins.

        New:  INERTIA LOCK RUBBER BUMPER REPLACEMENT.  The early '53 rubber bumper that the inertia lock arms rest on were thicker, allowing less arm travel.  Later in the year, they were replaced with thinner ones, allowing greater  arm travel.  The thicker ones may have prevented the arm on occasion from coming down and not letting the seat to move forward when the rear passengers were entering/exiting.

        I replaced the thin ones and made thick ones for our '53.  Mine are made to keep the arms in the locked position.  I found when I repeatedly tested the lock arms, they didnt always work, and when they dont work, the seat can freely move forward and back, possibly resulting in losing control of the car.  So for my rear passengers, I move the seat forward, Hydro-Lectrically, and fold the seat back inward and there is plenty of room to get in and out, and its safe!  I did find what seems to be a contradiction in the Buick Shop Manual and the '53 Buick Owners Manual.  The Owners Manual refers to the rear passenger inertia lock mechanism as slide away seatand is on the passenger side only.  Yet the Motors Manual does not mention one side, but both sides as found on our car.  I bought another set of tracks from our Buick Buddy Keith, and his tracks were set up the same as mine.  Both sides have inertia lock arms that override the Hydro-Lectric travel when the seat backs are folded inward.

        The seat track assembly is attached in the front to the Hydro-Lectric unit with a V pivot plate.  It is attached to the equalizer bar (that connects left and right seat tracks).  The bar connects on each track at two points with Cclips.  When the Hydro-Lectric switch is activated, the entire Hydro-Lectric seat unit kicks up at the front (remember its only connected to the floor board at the rear of the unit) and rotates the equalizer bar and moves the seat in the direction of the switch position.  When the switch returns to rest, the seat is locked in place by fluid trapped in the line and the relaxed position of the bar.  The top track is now locked to the bottom track and will not move unless operated by the switch or overridden by the inertia lock slide awayseat function.  

        When we checked our seat tracks to find out why they were locked up, we discovered some one had put a large sheet metal screw in each track to lock it up!  This probably happened when the Hydro-Lectric unit stopped working and they locked the seat in a position that was right for them.  I wish people would keep project books!!  A lot of time was spent to find this.

        We removed the connector bar, removed the screws and greased the tracks with an air grease gun to get into all the parts of the tracks.  

        The construction of these tracks is:  The lower track is riveted onto the bottom section which bolts to the floor board.  The top and lower tracks are separate and ride on ball bearings moving freely when in the neutral position.  The seat and connector bar connect to the top track. With the tracks free, we reconnected the connector bar and set the track without the seat cushion back into the car, bolted it down and hooked up the Hydro-Lectric unit.  The seat track now moved forward and back correctly.  Great news!!  Now for the installation. . .

        Originally, the seat track bolt holes were round holes in the front and oval holes in the left rear track.  This was to keep the front stationary while the rear could be brought into alignment by moving the track rear in or out as needed.  This kept the tracks from binding.  Our original tracks had all of the holes ovalled and so were the bolt holes on our extra set of tracks.   This was probably done for track alignment over the years.  As the seats were removed for servicing.  With the Hydro-Lectric system working and the seat tracks sliding, we were ready to install the seat.  Instead of using the original bolts through the seat tracks to the floor boards, we put in 5/16 f/t stainless steel studs and ran them down so we could just get a star washer and nut, then tested the seat frame movement.  We would have to shave a little off of the back ones, as the seat frame scraped in the far rearward position.  But we would wait until the final seat installation.

        We assembled the seat bottom cushion to tracks outside of the car.  In the front, there is only one bolt.  However, the rear mounting bracket rotates and is made so that one side is higher than the other, to fit the bottom side of the seat frame.  The higherbracket surface is positioned toward the outside of the car and the lower side toward the inside of the car.  We bolted the tracks to the seat bottom, put masking tape over our floor studs to protect the threads and lowered the seat to the floor.  Everything fit beautifully.  The star washers and nuts were tightened down, then we ground a little off of the high stud in the rear, making the track clear and still making it able to remove the hex nuts later if there is a need.

        To connect the Hydro-Lectric unit to the seat V plate, we toggled the switch to move the unit until it was directly under the Vplate, dropped in the bolt, star washer and nut, and it was locked down.  Now all that was left were the seat backs.  Each seat back has a slotted stud on the inner side that fits into a slot in the center hinge of the bench seat.  The seat backs are turned inward, pushed into the slot and rotated back, locking them in place on the inner hinge.

        To install the seat backs to the tracks, first slide the actuating plate into the groove in the upper seat track (this connects the actuating plate to the track and allows the seat frame hinge pin to slide through the rear hole in the seats outer hinge.  A 7/16 spring washer and a cotter pin go here.  The front hole of the seat hinge to the left of the above slides over the actuating plate pin, but does not get a cotter pin.  The seat is now done.  All that's needed are the side cover panels.

        The Hydro-Lectrics are finished, and we can continue with the interior installation.  There's always a challenge with old cars.  Never give up!  And keep 'em driving!

Our thanks to Hydro-E-Lectric, who supplies our cylinders.