Hydraulic windows - 1949 Cadillac

[Leif in Calif]

There's a 49 Cadillac on the "not Mine" forum that mentions hydraulic windows. I remember my sister had a '50 Buick Roadmaster Convertible that they said had them as well. Are they truly hydraulic? Seems like a very complicated way to make a window go up and down. 

[Bhigdog]

Yes...........Bob

[West Peterson]

Packard started using hydraulic windows in 1941. If you find one that works really well.... it's probably been converted to electric.

[dalef62]

Lincoln's used hydraulic windows in the 40's.  From my understanding when you hit the button to put the windows up the hydraulic motor ran and forced the cylinder/window up.  When it was time to put the window down you hit the button to put them down and it just released the fluid from the cylinder and the window went down with help from a couple springs on the window scissors, forcing the fluid back into the reserve near the hydraulic motor.

[46 woodie]

The Ford Sportsman also had hydraulic windows from 1946 to 1948. Most of the design and engineering was from the Lincoln.

[8E45E]

26 minutes ago, dalef62 said:

Lincoln's used hydraulic windows in the 40's.  From my understanding when you hit the button to put the windows up the hydraulic motor ran and forced the cylinder/window up.  When it was time to put the window down you hit the button to put them down and it just released the fluid from the cylinder and the window went down with help from a couple springs on the window scissors, forcing the fluid back into the reserve near the hydraulic motor.

Understand, a single electric motor either under the hood on the firewall, or inner front fender powered a pump that forced hydraulic fluid out of a reservoir into individual cylinders below each window to raise it when the switch was activated.  At the same time the switch opened a solenoid valve for that particular window to allow the fluid to fill the cylinder and raise the window against the pull of the spring(s).   To lower the window, only the solenoid valve opened, and the hydraulic fluid reverse flowed into the reservoir below the pump under the hood.    When one checks the level of hydraulic fluid in the reservoir, all windows, convertible top, antenna must be in the 'down' position, and the seat must be in the rearmost position to be accurate.

 

Craig

[West Peterson]

45 minutes ago, dalef62 said:

Lincoln's used hydraulic windows in the 40's.  From my understanding when you hit the button to put the windows up the hydraulic motor ran and forced the cylinder/window up.  When it was time to put the window down you hit the button to put them down and it just released the fluid from the cylinder and the window went down with help from a couple springs on the window scissors, forcing the fluid back into the reserve near the hydraulic motor.

Before the war, they were vacuum operated, if I remember correctly.

[8E45E]

1 hour ago, Leif in Calif said:

There's a 49 Cadillac on the "not Mine" forum that mentions hydraulic windows. I remember my sister had a '50 Buick Roadmaster Convertible that they said had them as well. Are they truly hydraulic? Seems like a very complicated way to make a window go up and down. 

I you want one that's really complicated, buy yourself a Mercedes Benz 600.  Besides the windows, the suspension/self-levelling, seats, sunroof, trunklid, door latches/locks are all hydraulically operated by a belt-driven pump from the engine.  

 

Vraig

[TAKerry]

I had a buddy that had Kenworth aerodyne. I think the windows were hydraulic, may have been pneumatic. Only time I had ever seen such a thing. They sure worked smooth.

[Bhigdog]

Lockheed, the aircraft company, LOVED hydraulics. If it moved it was pretty much hydraulic. The joke was if it could  Lockheed would use hydraulic light bulbs............Bob

Edited April 10, 2023 by Bhigdog (see edit history)

[8E45E]

1 hour ago, TAKerry said:

I had a buddy that had Kenworth aerodyne. I think the windows were hydraulic, may have been pneumatic. Only time I had ever seen such a thing. They sure worked smooth.

Most likely, compressed air.  Peterbilt, Mack, and Freightliner had air windows, most commonly on the passenger side only.

 

Craig

[dictator27]

2 hours ago, 8E45E said:

Most likely, compressed air.  Peterbilt, Mack, and Freightliner had air windows, most commonly on the passenger side only.

 

Craig

Definitely compressed air, almost always passenger side only.  The first British car to have hydraulic power windows and top was the Austin A90 Atlantic.  Even beat Rolls Royce!

 

[8E45E]

1 hour ago, dictator27 said:

Definitely compressed air, almost always passenger side only.  The first British car to have hydraulic power windows and top was the Austin A90 Atlantic.  Even beat Rolls Royce!

 

Peterbilt offered both air and electric windows in the trucks.

 

I believe the 1948 Jensen PW 4-liter convertible sedan had electro-hydraulic top and windows a couple of years before the Atlantic.

 

[c49er]

8 hours ago, 46 woodie said:

The Ford Sportsman also had hydraulic windows from 1946 to 1948. Most of the design and engineering was from the Lincoln.

That must have been awful when fluid leaked inside the doors or 1/4 panel and dribbled out all over the bottom wood door frame staining the wood.😒

[8E45E]

9 minutes ago, c49er said:

That must have been awful when fluid leaked inside the doors or 1/4 panel and dribbled out all over the bottom wood door frame staining the wood.😒

It was more than 'awful'.  Hydraulic fluid absorbs moisture in the worst possible way like brake fluid does, and permits rust. I've seen a Packard convertible where only the door bottoms were rusted through because of leaky cylinders.

 

Craig

[Dennis Hagen]

My 51 Super convert was all hydraulic windows and top. Switched to electric and everything works well.

[4Hud]

Another unusual power window mode of movement is our 1951 Frazer Manhattan 4 dr. hardtop. The actuator works on a vacuum cylinder in each door, we tried to rebuild it but with the heavy spring inside your body parts may be in peril during disassembly. The front doors still work well but use electric motors in the rear.

[61polara]

Hydraulic windows began around 1941 and lasted through the early 1950's.  Chrysler was the first to change to electric windows in 1951 or 1952.  GM made the change in 1954.  These systems used brake fluid in the system and it was recommended to change the fluid every six months because of water absorption in the fluid.  When a car with these systems sits, the fluid will slowly leak past the valve at the bottom of each cylinder and the windows will slowly come down and cannot be raised until the electric pump is run.  Besides brake fluid absorbing moisture, it has poor lubricating properties.  When the window is up, the rod from the cylinder is extended and will slowly begin to build corrosion on the rod.  These rods (pistons) are chrome plated to slow this, but it still occurs over time.  When the window is lowered, the corrosion will begin to cut the top seal on the cylinder and fluid will begin to seep out.  Brake fluid is one of the best paint strippers available; so when enough brake fluid leaks out, it will strip the paint off the door and sill.  If you have a car with this system, you should change to automatic transmission fluid in the system, which will keep the rod in the piston lubricated and will not strip paint if the system begins to leak.  The conversion to ATF requires that the rubber hoses in each door and the seat be changed to new hoses that are compatible with ATF.

 

Our cars have been using hydraulic power top systems for years which is a very similar system to the windows.  These systems can be very reliable but should be operated frequently to keep the cylinder rod lubricated after the system is converted to ATF.

[8E45E]

20 minutes ago, 61polara said:

If you have a car with this system, you should change to automatic transmission fluid in the system, which will keep the rod in the piston lubricated and will not strip paint if the system begins to leak.  The conversion to ATF requires that the rubber hoses in each door and the seat be changed to new hoses that are compatible with ATF.

 

Our cars have been using hydraulic power top systems for years which is a very similar system to the windows.  These systems can be very reliable but should be operated frequently to keep the cylinder rod lubricated after the system is converted to ATF.

I have seen a number converted to ATF for that reason.  Changing the rubber lines from EDPM to a Buna nitrile rubber is essential so it doesn't swell up and break down.  This also applies to the seals and o-rings in the individual cylinders, and the hydraulic pump, which should also be changed over to be compatible with ATF.  

 

The only noticeable difference is ATF does compress some, where hydraulic fluid does not, and one may see the window 'bounce' slightly when stopped in a midway position.

 

I believe actual hydraulic fluid was used in the majority of original systems, as it did not have to withstand heat like brake fluid does.  

 

Craig

[61polara]

2 minutes ago, 8E45E said:

I believe actual hydraulic fluid was used in the majority of original systems, as it did not have to withstand heat like brake fluid does.

Most of the window systems I've seen used brake fluid and many convertible top systems used brake fluid through the early 1960's.  I don't know why they stayed with brake fluid for the top systems so long.

[60FlatTop]

20 hours ago, Leif in Calif said:

Seems like a very complicated way to make a window go up and down. 

Making them go down is not so complicated. Not at all.

[Marty Roth]

8 hours ago, 61polara said:

Most of the window systems I've seen used brake fluid and many convertible top systems used brake fluid through the early 1960's.  I don't know why they stayed with brake fluid for the top systems so long.

Maybe because Dot-3 was readily available?

 

My 1952 Cadillac convertible used brake fluid in a single system for all four windows, the front seat, and the convertible top. 

We replaced all seven of the cylinders, cleaned the switches, replaced hard and soft lines, and went back with Dot-5 silicone - no more problems!

 

Our 1954 Cadillac convertible top, seat, and windows are all electric.

 

6 hours ago, 60FlatTop said:

Making them go down is not so complicated. Not at all.

The springs pull them down.

 

Our 1941 Cadillac convertible cabriolet uses vacuum to raise and lower the top, and all else is manual.

[Cristian Ospina]

Hello, I have a 1950 Cadillac. After 7 years I managed to get the windows and seat to work.
https://www.youtube.com/watch?v=s7i4D1ARMUw

[Frank DuVal]

On 4/11/2023 at 7:26 AM, 8E45E said:

I believe actual hydraulic fluid was used in the majority of original systems

All the systems I have seen use DOT 3 from the factory, but I have not seen every early system!  The earliest I've personally seen was the 1950 Buick with DOT 3 in the hydraulic pump powering the windows, seats and top. The latest I have seen were mid 60 GM top systems that were DOT3 in the pump reservoir. 

 

Great video, Christian!👍

 

❄️🎄🎄🐖🍠🕎🦃

[arcticbuicks]

speaking of the semi trucks with air powered windows........some vintage semis even had air power steering 

[Ben Bruce aka First Born]

1 hour ago, arcticbuicks said:

speaking of the semi trucks with air powered windows........some vintage semis even had air power steering 

Yep.  I had a 1982 GMC Astro with Air Power Assist.   An air cylinder attached to the drag link on one end and the frame on the other. 

 

  Ben

[Omarine]

On 4/11/2023 at 6:55 AM, 61polara said:

Hydraulic windows began around 1941 and lasted through the early 1950's.  Chrysler was the first to change to electric windows in 1951 or 1952.  GM made the change in 1954.  These systems used brake fluid in the system and it was recommended to change the fluid every six months because of water absorption in the fluid.  When a car with these systems sits, the fluid will slowly leak past the valve at the bottom of each cylinder and the windows will slowly come down and cannot be raised until the electric pump is run.  Besides brake fluid absorbing moisture, it has poor lubricating properties.  When the window is up, the rod from the cylinder is extended and will slowly begin to build corrosion on the rod.  These rods (pistons) are chrome plated to slow this, but it still occurs over time.  When the window is lowered, the corrosion will begin to cut the top seal on the cylinder and fluid will begin to seep out.  Brake fluid is one of the best paint strippers available; so when enough brake fluid leaks out, it will strip the paint off the door and sill.  If you have a car with this system, you should change to automatic transmission fluid in the system, which will keep the rod in the piston lubricated and will not strip paint if the system begins to leak.  The conversion to ATF requires that the rubber hoses in each door and the seat be changed to new hoses that are compatible with ATF.

 

Our cars have been using hydraulic power top systems for years which is a very similar system to the windows.  These systems can be very reliable but should be operated frequently to keep the cylinder rod lubricated after the system is converted to ATF.

Hello Polara,

do you have a source for replacement parts for these pumps? I have moraine motovator that im restoring and all i need is the valve that goes in the casting under the spring and over the check ball. Part # 5453526. 
 

might need a machinist to make one but dont have dimensions. 
 

 

thanks

Oscar 

[demco32]

On 4/10/2023 at 6:57 PM, Leif in Calif said:

There's a 49 Cadillac on the "not Mine" forum that mentions hydraulic windows. I remember my sister had a '50 Buick Roadmaster Convertible that they said had them as well. Are they truly hydraulic? Seems like a very complicated way to make a window go up and down. 

the mercedes 600 has everything hydroulic.

[61polara]

2 hours ago, Omarine said:

do you have a source for replacement parts for these pumps? I have moraine motovator that im restoring and all i need is the valve that goes in the casting under the spring and over the check ball. Part # 5453526. 
 

Contact Hydro-E-Lectric

Hydro-E-Lectric (hydroe.com)

 

[61polara]

Automatic transmission fluid Type A can be used in these systems, but you must replace the rubber hoses.  DOT 5 brake fluid is not recommended as it does not have the lubrication properties of DOT 3 or Type A fluids.

[EmTee]

Today, Type A = Dexron III/Mercon ATF.

 

I'd also expect that power steering fluid could be used...

 

Edited February 18 by EmTee (see edit history)

[Omarine]

9 minutes ago, 61polara said:

Automatic transmission fluid Type A can be used in these systems, but you must replace the rubber hoses.  DOT 5 brake fluid is not recommended as it does not have the lubrication properties of DOT 3 or Type A fluids.

Thanks, the pump on my car works fine. I was restoring a 12v pump and now need the valve- any leads? 
 

cheers