1947 Lincoln window pump woes

[Sparkydave]

The pump was frozen from sitting for several years when I got the car earlier this year.  With a couple drops of oil I got the pump gears freed up, and I got a rebuild kit from Hydro-e-lectric.  I got the relief valve unstuck, got the motor shaft seal replaced, put the new pump gears in and lubricated them with brake fluid.  When I fill the reservoir with fresh brake fluid and hit the switch, the pump runs quickly for a second, then slows down.  The problem is it can't seem to build up any pressure, like the relief valve is stuck open.  I can get some fluid coming out of the end of the hose, but if I hook it up to the windows, the driver's window shows no signs of moving.  I have pulled the door panel off and confirmed the window cylinder moves freely if I lift the window by hand.  If I disconnect the hose from the firewall and put my finger over the end, I can easily stop the fluid and I can't feel any pressure behind it.

 

It seems to be behaving exactly like the relief valve isn't closing and the fluid is just returning to the reservoir, but I can't find anything wrong.  I took the pump out again, removed the relief valve spring again, and it moves freely.  Put the pump back in, and same thing, it runs but there's no pressure.  Help!  Any ideas?

[c49er]

Brake fluid?...even tho back in the day it was used...today use ATF.

Brake fluid is obsolete in hydraulic window and top systems.

It ruins paint too.

You need to replace all the hoses, rebuild the cylinders and clean and lube all the regulators.

The hoses are probably 75%+ closed up after all these years.

The pump cannot freely pump fluid and enough volume.

It needs a thorough cleaning and inspection. Gear/rotor clearances need to be checked too.

[Lee H]

If you are getting fluid flow, and no pressure, I’d suspect that the rebuilder got the relief valve spring length/tension wrong, or installed it improperly. It should be a fairly stout spring, but I don’t have a ready length for you…make sure it is actually seating the valve.

Edited November 14 by Lee H (see edit history)

[Sparkydave]

9 hours ago, c49er said:

Brake fluid?...even tho back in the day it was used...today use ATF.

Brake fluid is obsolete in hydraulic window and top systems.

It ruins paint too.

You need to replace all the hoses, rebuild the cylinders and clean and lube all the regulators.

The hoses are probably 75%+ closed up after all these years.

The pump cannot freely pump fluid and enough volume.

It needs a thorough cleaning and inspection. Gear/rotor clearances need to be checked too.

Since when is it OK to use ATF when there is a warning stamped on the reservoir that says "FILL WITH BRAKE FLUID ONLY CAUTION: DO NOT USE MINERAL OIL"?  Likewise the owner's manual and service manual say to only use brake fluid.  Since rubber parts compatible with brake fluid are easily ruined by anything petroleum based, please point me to your source saying it's OK to use ATF for that model year.

 

Do you know of anyone who rebuilds the window cylinders?  I've already asked on here, nobody had an answer.   I asked Hydro-e-lectric, since they rebuild the pumps, but they don't.  They sold me the rebuild kit for the pump, but they don't have a rebuild kit for the window cylinders.  Apple Hydraulics won't rebuild them either.  I've already replaced the hoses.

 

If you read my question, the pump has been cleaned and rebuilt with new gears, so the other suggestions don't answer the question of why the pump doesn't seem to make any significant pressure.

 

3 hours ago, Lee H said:

If you are getting fluid flow, and no pressure, I’d suspect that the rebuilder got the relief valve spring length/tension wrong, or installed it improperly. It should be a fairly stout spring, but I don’t have a ready length for you…make sure it is actually seating the valve.

The spring is installed the same way it was when I took it apart.  It is mating with the locating post on the valve, and it's definitely building tension as I tighten the retaining bolt.  Even if it had lost some tension over the years, the pump should still be able to create some significant pressure.  It takes zero effort to block the hose with my finger, and there are no signs the fluid is leaking outside the pump.

[c49er]

Gee sorry....find the answer you need that pleases.

[Sparkydave]

9 hours ago, c49er said:

Gee sorry....find the answer you need that pleases.

Answers with suggestions that can potentially cause a lot of expensive damage aren't very good answers if there's nothing to support them.  Sorry for questioning why you and others are suggesting just switching over to ATF or hydraulic oil when there's documentation saying not to do that.

[Sparkydave]

This pump is still giving me fits.  It's not making any sense.  If I unscrew the relief valve plug and pull the spring out, the relief valve moves freely.  I can energize the pump and it will shoot the relief valve out with copious amounts of fluid spraying out.  The pump runs at a high speed while that's happening.  If I screw the plug in part way with the spring with some light spring tension, the pump slows down a little and there's fluid coming out of the hose, but with not much pressure.  If I tighten the plug down, the pump runs slower and slower with more spring tension, and it's obviously working very hard because the solenoid terminals are getting hot.  If I tighten it down with the same 4 spacing washers as it had originally, the pump is running very slow, and there's little or no fluid coming out of the hose.  I put the old relief valve and spring in, and it's the same thing.

[roysboystoys]

I would suspect a short in the windings of the motor, not allowing full power or speed.

[Sparkydave]

I guess that is a possibility, I had stuck a battery in it and tried putting the windows up before I had it shipped, not knowing the pump gears had frozen up.  I thought the "click" I was hearing was just the solenoid valves and the pump solenoid wasn't turning on.  When I got it here and started trying to fix it, that's when I found the solenoid was working but the motor was pulling lots of current because it was stuck.  Although it was only for a couple seconds, perhaps the motor was damaged when it wasn't turning.  I have another pump in my parts collection, maybe I can try swapping this pump assembly onto the other motor.

 

The copious amounts of touch up paint along the bottoms of the doors and the fact that dad was never able to leave the windows up for more than a day or two before they would start leaking down are reminding me why these hydraulic windows were definitely "bleeding edge" technology in 1947.

[61polara]

On 11/15/2024 at 10:11 AM, Sparkydave said:

Answers with suggestions that can potentially cause a lot of expensive damage aren't very good answers if there's nothing to support them.  Sorry for questioning why you and others are suggesting just switching over to ATF or hydraulic oil when there's documentation saying not to do that.

There may not be factory documentation, but there is a good reason for it.  Brake fluid is hydroscopic so it absorbs water.  The factory manuals state to replace the fluid every 6 months.  This is to remove water contaminated brake fluid.  There is not this concern with a brake system, because the heat from the brakes will boil off the water.  Water in the window system will cause the rods that move in and out of the cylinder will corrode and will cut the seals at the top of the cylinder.  Transmission fluid will leave a film of oil on these rods to prevent or at least slow down the corrosion.  

 

The factory manuals say not to use mineral oil in the system.  This is because the rubber hoses are not compatible with oil and must be changed when you convert to ATF.  Convertible top systems are basically the same as your window system.  Many cars used brake fluid in the top systems through the early 1960's.  Then they all changed to using ATF.  I think that is good enough documentation for me.  

[Sparkydave]

On 11/26/2024 at 1:20 PM, 61polara said:

The factory manuals state to replace the fluid every 6 months. 

Oh?  What factory manual says that?  The 1942-1948 Ford/Mercury/Lincoln manual says every fall.  So does the original 1946 Lincoln Operator's Manual my dad managed to find.

 

Not sure how you're making the connection that since later cars used ATF for their convertible tops that it must be OK for an older car where you've stated the hoses are not compatible with ATF.  What leads you to believe the window cylinder seals are compatible if the hoses are not?  Not trying to be difficult, but I'm not gambling with unrebuildable window cylinders.  I have no problem changing the fluid every year, but obviously ATF would be more desirable than brake fluid.  I'm replacing the hoses, and the new ones appear to be off the shelf hydraulic hose.

[c49er]

Wow...is all I can say.

[old car fan]

Atf works,i dont know why you will not listen to suggestions. We have atf in ours,probably 10 years, no problem, no changes. Top,windows, work  perfectly. Couldn't imagine  a restored  car,breaking a line,with brake fluid. Have you checked the pump pressure?