Six Decades Ago, Ford Figured Out How To Use The Power Steering Pump To Clean The Windshield

If I asked you to think of a car with weird windshield wipers, what would you suggest? Perhaps you’d mention the Tesla Cybertruck, with its massive swooping blade, or the triple-arm setup on the glorious Toyota FJ Cruiser. But there’s an altogether stranger solution out there, from one of the most conventional automakers on the block. I’m talking about Ford and its powerful wiper systems from the mid-1960s.

The vast majority of windscreen wipers work in the same way. They use an electric motor of conventional construction, paired with some gearing and linkages to create the appropriate back-and-forth swooping motion that clears your windscreen of water. Electric motors make sense—they provide enough torque and power to do the job, and powering them is as simple as running a couple of wires.

However, if there’s a way to overcomplicate a system and increase the likelihood of leaks and failures, you can bet at least one automaker has tried it over the years. That’s what led Ford to develop an all-hydraulic windscreen wiper system.

Pump, Pump It Up

Today, we take windscreen wipers for granted. At the flick of a switch, we can have them swishing back and forth to clear the view ahead at a range of speeds to suit our desires. However, it wasn’t always thus. In the earlier days of the automobile, wipers weren’t nearly so good.

A full history of the windscreen wiper would be too long and tedious to explore here. Suffice to say, in the earlier part of the 20th century, there were two major types of wipers used across most of the automotive industry. Vacuum-powered wipers were popular with many automakers, relying on vacuum generated by the engine itself to power the wiper motors. This was an imperfect solution, as wipers would slow when engine vacuum was low—such as when throttle was wide open during high-speed driving or during a hill climb. Wiper speed control was also difficult to achieve; it wasn’t even considered as a feature in this era.

Vacuum wipers: universally considered to be a bit crap.

Alternatively, some brands, like Chrysler, instead chose to adopt electric wipers as early as 1940, which didn’t suffer this problem. Meanwhile, a more obscure solution was to go the mechanical route. The early Citroen 2CV was an example of this method, running its wipers off a cable hooked into the transmission, along with the mechanical speedometer. [Ed Note: Some Willys Jeeps ran wipers off the vacuum created by the mechanical fuel pump. These were failure prone. -DT]. 

Come the 1960s, though, Ford went a rather unique route of its own. It decided that windscreen wipers should be hydraulically driven—with hydraulic power supplied by a vehicle’s existing power steering pump! Ford most notably used these on the 1961 to 1969 Lincoln Continental, the 1963 to 1971 Ford Thunderbird, and select models of the 1969 to 1971 Lincoln Continental Mark III.

This method had a number of benefits. For one, an engine-driven power steering pump could provide plenty of excess power to run the wipers. There would be no issues with weak running at speed like vacuum wipers, since even at idle, the power steering system would have plenty of hydraulic pressure on tap. This was particularly useful for drivers in snowy climates or those with heavy rain, where powerful wipers are a big help.

Variable speed operation was also straightforward, simply by metering the flow to the hydraulic wiper motor. The concept was not altogether different to Jeep’s hydraulic cooling fans used in the early 2000s. The power steering pump was a straightforward source of hydraulic power that could be used to run a simple mechanical accessory.

However, hydraulic wipers also had their drawbacks. They required running hydraulic lines from the power steering pump up to the cowl, where the wiper motor was mounted. This was messier compared to electric wipers, which just required a couple of thin wires to run to the cowling. Extra lines attached to the power steering system meant there were more hoses to potentially leak. It also meant that if the power steering pump failed, you’d also lose the use of your wipers. Beyond this, a lot more could go wrong with a hydraulic wiper motor over the years. They were reliable enough in use, but still far more complicated and with many more seals and gaskets compared to a simple electric wiper motor.

The wiper motor also usually featured a small filter for the power steering fluid. If this became clogged, it could hamper the performance of the steering and wipers alike. This could go unnoticed, as few owners were regularly thinking along the lines of “hey, I really should check my wiper motor fluid filter this fall.”

Even on this beat-up old 1968 Ford Thunderbird, the hydraulic wipers are powerful and fast.

GMC used hydraulic wipers on some motorhomes in the mid-1970s.

There is also one minor use case in which hydraulic wipers are inferior to the electric type. If your engine isn’t running, you can’t use the wipers. With the engine off, the power steering pump isn’t running, so there’s no hydraulic pressure to move the wipers. If you’re sitting in your parked vehicle and you suddenly need to see through the windscreen on a rainy day, you’ll need to start the engine.

The wipers used a small hydraulic motor that was attached via hydraulic lines to the power steering pump and the steering box. The lines were routed via a dashboard mounted control that could vary the speed of the wipers as desired. The technology used by Ford was referred to as Hydro-Wipe, and was developed by a supplier named Trico. In a beautiful nod to journalists of the future, the company was kind enough to emboss the relevant patent numbers for the technology right on the wiper motor castings.

Trico filed several patents from 1954 to 1963 regarding the design of its hydraulic wiper systems. A particularly early filing suggested using hydraulic pressure generated by an automatic transmission. A later patent considered running a secondary pump using engine oil to provide power to the wipers.

It was only in later filings from 1959 onwards that Trico settled on using the power steering pump to provide hydraulic power for the wipers. This allowed for a less invasive install that didn’t risk damage to the automatic transmission or engine if there was a leak or something else went wrong.

Diagram from Trico’s patent, regarding the combined reciprocating hydraulic motor and speed-control metering valve. Credit: USPTO

The hydraulic motors used in Trico’s wiper mechanism were not a typical continuous rotation type. Instead, they featured a complicated reciprocating mechanism that saw fluid passed to either side of a vane as it turned back and forth through 180 degrees. Paired with the appropriate wiper linkages, this mechanism allowed for the predictable back-and-forth motion desired for wiping a windscreen.

Built into the base of the motors was a cable-controlled hydraulic metering mechanism. A control in the cabin tugged on the cable, which adjusted the hydraulic pressure reaching the motor via an in-built piston-type valve. The greater the pressure sent to the motor, the faster the wipers would move.

The hydraulic motor was a sizeable unit that lived under the windshield cowling. 

Ford eventually abandoned hydraulic wiper motors, with the technology effectively disappearing from the lineup in the early 1970s. The Blue Oval largely went to electric wipers and didn’t look back. Notably, Trico found another customer, with some GMC motorhomes in the picking up hydraulic wipers in the mid-1970s.

Some classic Fords and Lincolns still get around with hydraulic wipers today. If properly maintained, the wipers still do the job—and with better performance than Ford’s earlier vacuum-powered wipers, too. However, there are options for those that tire of the complicated hydraulic setup. It’s possible to buy kits to convert these older vehicles to use a more typical electric wiper motor instead.

It’s not exactly clear why Ford went the hydraulic route in the 1960s. While it was an obvious upgrade over weaker vacuum systems, electric wipers were becoming fairly well established in this time period. At the same time, engineers back then weren’t so afraid of a little mechanical complexity. The internal combustion engine was still a marvel, less than a century old, and so were automobiles that could fling themselves down highways at triple-digit speeds. Ford engineers likely decided the wipers could have a little additional hydraulic circuit, as a treat.

Regardless, in this modern world, such oily, mechanical contrivances are very much a thing of the past. No serious automaker would consider running expensive high-pressure hydraulic lines where a couple of cheap wires would do. Similarly, electric motor technology is so advanced, and economies of scale so established, that prices are rock bottom for electromechanical devices. No complex hydraulic motor with many delicate moving parts could ever hope to compete. Hydraulic windscreen wipers will remain a curio of the 1960s, just one that isn’t as well remembered as the Apollo program, the Grateful Dead, or the San Francisco acid tests. Perhaps, a shame!

Image credits: Ford, US Patent Office, eBay