Hydro-lectric window fluid

[Fleetwood Meadow]

I have original window cylinders in my ‘52 Cadillac. That means I need to use brake fluid in them. They say that if I use ATF in them the original rubber in he cylinders will get destroyed. But the advantage to ATF is they claim it doesn’t need to be changed yearly. However, they say that the dot 3 brake fluid that is used needs to be changed yearly due to the absorption of moisture into the fluid. The new cylinders can use ATF but are expensive. With new fluids, such as dot 5, a silicone based fluid which they claim does not absorb moisture, can that be left in the system without the yearly fluid change?

[Coley]

Don't see why silicone Dot 5 wouldn't work.  Used it in my 1933 Chevy for over 30 years with no problem. Street rod, not original cable brakes.

[c49er]

The right answer is ATF in new cylinders and new pump.

It's just a pump and hydraulic cylinders like a car lift or P/S system... use a safe, clean, cheap long lasting fluid.

[61polara]

DOT 5 doesn't have the lubricating properties needed in the system and should not be used.  ATF is the best choice.  Remember DOT 3 is a great paint remover.  I had a 1948 Cadillac that developed a leak in a door cylinder and stripped the exterior paint off the bottom half of the outside of the door.  In changing to ATF, you will need to replace the rubber lines as well with new rubber.

[Fleetwood Meadow]

Thank you for the great responses. It sounds like it is an expensive system. So bottom line, if I want to use ATF I need to spend $600 on cylinders and another $100 on rubber lines. Doesnt sound like a great use of money. Unless someone knows where I can buy 4 window cylinders and an underseat cylinder for less. 

Edited April 1, 2019 by Meadowfleet (see edit history)

[Spinneyhill]

Do you need new cylinders? Just the rubbers in them is all you need, surely? Something that will handle ATF. The steel will be OK. But everything will need a thorough wash out to remove the brake fluid first.

[Fleetwood Meadow]

I was told that the cylinders can not be taken apart, they are sealed units. 

[61polara]

I feel your pain.  I have a "48 60 Special and a "53 Series 75.  Remember there are 5 cylinders including the power seat. Do it right and change to ATF.  You might try changing the rubber lines and flush and keep your original cylinders and run them until they leak.  It won't damage the paint only cause a mess.  Want to buy a "53 Series 75?  Make me an offer...….  Be serious, I may take it.

Edited April 2, 2019 by 61polara (see edit history)

[Fleetwood Meadow]

 What’s it look like? You can pm me that so it doesn’t distract the thread. If I am not mistaken ‘53 went to 12v and electric windows, didn’t it?

Edited April 3, 2019 by Meadowfleet (see edit history)