1968 power steering system bleed

[jon774]

Having issues with the power steering system. This is connected to the hydraulic wipers. All functions feel normal however I get a fluid burp out of the PS pump every once and a while. It's about 1/3 pint of fluid. It's enough for me to avoid my asphalt driveway.
I have bled the system by opening up the reservoir and turning the wheel all the way right then left. I've done this a few times and still the burb.
Seems to me they should have a bleed screw at the wipers, being the highest point in the system.
Any thoughts?

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[74 Harley]

Since the system is pressurized flow "bleeding" is not a real necessity.
Turn the wipers on for a few cycles and go lock to lock with the steering. That will get the air out of the system.
At what point are you having issues? After driving, when real hot or cold? Is the system being overfilled? Does it have a cooler? Is it leaking?

 

[jon774]

Since the system is pressurized flow "bleeding" is not a real necessity.
Turn the wipers on for a few cycles and go lock to lock with the steering. That will get the air out of the system.
At what point are you having issues? After driving, when real hot or cold? Is the system being overfilled? Does it have a cooler? Is it leaking?

It happens after I drive or run it for any amount of time. The amount it burps out requires me to refill it. I know this because it doesn't register on the dipstick after warm up as well as the pump whining at idle. When I fill it I just fill it to register, basically just to cover the inside "bell" of the reservoir. There is no cooler. The wiper motor is always active because I haven't attached the cable or wiper arms. I'm going to get a vacuum pump and see if it hold vacuum. I suspect a leak but it's hard to find because I always have fluid dripping from the burp. I had this problem ever since I reattach the wiper motor and related hoses. There is no leak, that I can see from those connections. But reason suggests there lies the issue.
Thanks for your help.

 

[74 Harley]

It sounds like you are not overfilling it. Do you have a diagram of the hose connections for the wipers? Maybe one of the wiper motor hoses is in the wrong place.
Or maybe a previous owner eliminated a cooler.
If I remember correctly many Fords used the return line with a hoop and fins for cooling.

 

[jon774]

You can't mix up the inlet or outlet on the wipers as they are sized different, however it's a good point. I will look through my books and pics find a hose diagram or layout. I don't think this year had a cooler. I had two of these cars and made one. I had no cooler on either.

 

[74 Harley]

if you have an infrared thermometer try taking temp of the power steering pump and fluid. You may need to add a cooler. Sounds like you know what you're doing.
Good luck!

 

[jon774]

How hot is too hot? I'm using type F ATV. I will have to see if the fluid grows as it keeps getting hotter or if there's a growth limit after it reaches a certain time.

 

[74 Harley]

Great question, I don't have a great answer. I would be concerned over 160, but maybe do a temp check on a similar vehicle after a drive. At least it will give you something to compare to.
The fluid will expand at least 10 percent by volume from cold to operating temperature.

 

[74 Harley]

As a side note back when I used to build off road vehicles I built an early Bronco with a locked front end. The first time out it boiled the steering fluid in 20 minutes. I had to add a one quart filter and used a trans cooler to get it to work properly.