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1 HYDRO-LECTRIC SYSTEMS. INTRODUCTION AND COMPONENTS, PART 1. The answer, in regard to convertible tops, was By Clay Mollman, St. Louis, Missouri no. The Hydro-Lectric had a powerful central pump 1998 Clay Mollman utilizing a motor like a starter motor, and it could be located out of the way on the firewall. The two side WEBMASTER'S NOTE: This series is being reprinted at cylinders which raised and lowered the top needed the request of NAOC members. Originally written in to have force applied evenly and in a manner that 1998, the author is no longer living. The Webmaster would not jam the complex pivots of the top frame. nor the NAOC assume any responsibility for the ac- The equalizing effect of a hydraulic system handled curacy of the information contained here. this requirement well. Earlier systems of vacuum tops were underpowered and did not do well.

2 The This is the first of an nine-part series on General 1942 98 used an electric motor and cable system Motors Hydro-Lectric systems used from 1946 for all 216 cars produced, and that system, gott sei through 1954. dankt, was never seen again. More advanced electri- cally driven tops using cables and motors came later. Hydraulic systems to operate power convert- For the windows the answer was also no. In ible tops and power windows were developed prior 1955 twelve-volt electrical motors were introduced to World War II for use in luxury cars, and after the to drive power windows, but in 1946 there were war were used in Oldsmobile 98 s, Buicks and Cadil- no six-volt electrical motors with adequate torque lacs. This series of articles will describe the opera- that would fit inside the door. General Motors did tions, maintenance, troubleshooting and repair of not think that it was worth changing from hydraulic these systems.

3 Window operation until the third year of the 12 volt To set the stage, in an earlier article I referred electrical system. to these systems as an invention of the devil. In In Oldsmobiles, the Hydro-Lectric system for retrospect, I may have been unfairly harsh with the power windows, seats and top was standard equip- devil. Hydro-Lectric systems worked well when they ment on 98 convertibles from 1946 through 1954. were fresh out of the factory, but when they got old In 1949 it was standard on the 98 Holiday Coupe for they became cantankerous, evil-smelling and hard power windows and seats and from 1950 through to deal with, not unlike some old car buffs. In my 1954 it was standard on the deluxe models of the youth in the early 50s, it was frequently easy to spot 98 Holiday Coupe. From 1946 Hydro-Lectric power a Buick or Cadillac with power windows.

4 They com- windows and seats were optional in 98 sedans and monly had rusty rocker panels where the hydraulic club sedans. The other C bodied GM cars from Buick fluid from the window units leaked and cleaned off and Cadillac came the same way. In addition, Cadil- the paint. The Ford Skyliner retractable of 1957 was lac provided a power division window for the 75 . a marvel of simplicity and reliability compared to limousine. these systems. From 1946 a simplified Hydro-Lectric system If the system was so expensive to build and for the power top only was used in 60 series, 76 , so troublesome to maintain, a reasonable question 88 and Super 88 convertibles, with similar offer- might be to ask whether there couldn't have been ings from Chevrolet and Pontiac. some better way to approach the problem. On the firewall next to the left hood hinge is the quarter window regulator removal and service the body and style plate from Fisher Body, which had and some on the wiring, but nothing on the pump an X suffix for cars with a Hydro-Lectric systems.

5 Or convertible top. This is the only direct description I know of for the 1948-49 98 bodies. Hydro-Lectric SYSTEM COMPONENTS was standard on these three late-entry '49 hardtop The Hydro-Lectric system, taken from 1946 models. through 1954, consisted of these components: The 1950 Shop Manual also ignores the Hy- 1. Central hydraulic pump, electrically driven. dra-Electric and the 1951 year was covered by a sup- 2. Fluid reservoir. plement at the back of the 1950 manual, so it avoids 3. Single-acting hydraulic cylinders for the win- the issue also. How strange it is that General Motors dows and seat. installed an expensive and troublesome system in its 4. Double-acting hydraulic cylinders for the most expensive cars and from 1947 until 1952 chose convertible top. to tell the average guy at the dealer shop absolutely 5.

6 Steel tubing plus flexible rubber hoses to tie nothing about it! it all together. They shaped up in 1952 with an entire 22. 6. Electrical switches for the doors and win- page section of the shop manual devoted to the dows. Hydro-Lectric system, including the new variants of 7. Control valve for the convertible top. trunk-mounted hydraulic pumps on 88 s and trunk mounted, electrically operated control switches on What's In the Shop Manuals the 98 convertibles. The shop manual might contain a lot of For all years, the hobbyist should check the information and it might ignore the Hydro-Lectric, Body Parts Manual, which contains excellent photos depending on the year. and drawings of all the Hydro-Lectric components The 1947 Fisher Body manual is excellent with their parts numbers. Some of the illustrations in with about 40 pages on the system, covering pumps, this series are from body parts manuals.

7 Cylinders, top operation and wiring. The 1949 Olds Shop Manual absolutely ignores it, without even a Next: Principles of operations of the Hydro-Lectric. mention of any of the components in the index. The 1949 Fisher Body Service and Constriction Manual Suppliers refereed to are: Fusick Automotive Prod- for the Special Sport Coupe ( 98 Holiday, Buick ucts, PO Box 655, East Windsor, CT; Precision En- Riviera and Cadillac Coupe de Ville), has excellent gineering, PO Box 1294, Canyon City, CO 81215;. coverage of the seat adjuster, door window and Hydro-E-Lectric, 48 Appleton, Auburn, MA 01501;. Steele Rubber Products, 6180 Highway 150 East, Denver, NC 28037. HYDRO-LECTRIC SYSTEMS: PRINCIPLE OF OPERATION, PART 2. By Clay Mollman, St. Louis, Missouri the motor off, there is no pressure in the system, and 1998 Clay Mollman the force of the springs silently pulls the window down, and pushes the hydraulic fluid back through This is the second of an nine-part series on Gen- the same tubing into the reservoir at the pump.

8 Eral Motors Hydro-Lectric systems used from 1946 The mechanism for moving the front seat back through 1954. and forth works exactly the same way. When the sole- noid valve at the seat mechanism is open, springs pull Last month we described the major compo- the seat to the rearmost position. nents and this month we will describe the principles of operation for the Hydro-Lectric system, looking at Convertible Top Operation Convertible top cylinders are double action, the windows and seats first, and then the convertible that is, they have inlets at both ends of the cylinder. top operation. Pressure in one inlet moves the piston away from it, Window and Seat Operation pressure in the other inlet moves the piston back. When a window is down and the switch in the The window cylinders had an inlet at the bottom door panel is pushed to the up position, two things only and the coil springs provided power for the happen.

9 First, current goes to a relay at the hydrau- down direction. lic pump motor at the firewall, starting the motor The top switches for convertibles are of two and pumping up the entire system all the window types, but they operate in about the same way. For cylinders and the top control switch, to about 250 all Hydro-Lectric 98 convertibles before 1952 there pounds per square inch. The motor draws 95 amps is a control valve under the dash. It is operated by to do this. Second, the door switch sends current to pulling the TOP knob out to put the top down or a solenoid-operated, normally-closed valve at the pushing the knob in to put the top up. The valve has base of the selected window cylinder, causing it to a center neutral position with a spring return. The open. Hydraulic fluid moves the cylinder piston up, dash knob is connected to a pivoting rotary valve and the window goes up.

10 It is pushed up against the attached to the stationary control valve body. The force of a pair of powerful coil springs in the win- valve body has two hydraulic lines from the pump, dow regulator assembly. When the door switch is one connected to the pressure side and one serving released, the pump motor stops and the current to as a return to the reservoir. There are two hydraulic the selected window cylinder solenoid stops, caus- lines coming out of the valve, one goes to the bot- ing the solenoid valve to close by an internal spring. toms of both convertible top lift cylinders and pres- Hydraulic fluid trapped in the selected window cyl- sure there makes the top go up. The other line goes inder by the solenoid valve is compressed by the coil to the tops of both top lift cylinders and pressure springs. As long as the solenoid valve remains tightly there makes the top go down.