How do you stop power steering fluid from foaming?

I have a new powersteering pump, lines and steering box in my 78 and Type F fluid. The pump is making the fluid bubbly with foam and it overflows the cap. Then once the bubbles settle out it is low on fluid. So I refill it to the appropriate level and next thing I know its overfull again (because of the foaming) and overflowing.

Any ideas what would cause this?

 

the only time i saw this was when we pulled a pump from a bone yard. found out the the pully size was different. when we swapped the pully it was fine

 

sigtauenus sounds to me like the system was not bled correctly.
Turn the wheels from lock to lock & just hold it ther for just 1 sec
i would highly recomend using mercon 3 or 5 for this to be done
for the last time. This is far from uncommon with power strreing systems. good luck turbo ted

 

you mean bleed the system with mercon 3 or 5, or use that altogether with my power steering?

 

sigtauenus drain entire system & then replace with mercon 3or5
then bleed the system. If this still happens after this you may
want to install an orifice tube on the low pressure side to see
what is being suspended in the fluid as you drive & then check it
out in a week or two i always recomend one with the sale of new
power steering pump or lines it is cheap & worth the piece of mind
you may also want to consider using some synthetic atf instead of
mercon 3or 5 now just by design it is very hard for the synthetic to foam up. It has been my experience that using the synthetics in
with a new pump & flushing the lines before the synthetic fluid you will probally never have to replace the pump. I do not know if you remember in the 80's the power steering pumps back then on
the fords were noisy & the rack & pinions would get stiff on a cold morning, in my fords i was always asked why is yours not noisy & i would explain that it was due to the synthetic fluids & never had a pump go bad on me due to fluid break down.
turbo ted

 

Good info, thanks!

 

6 years later I rebuilt the system again and didn't need a new pump, but the gear was shot so I replaced everything at the same time. Rebuilt gear from RedHead in WA, new hoses and rebuilt pump.

I couldn't find synthetic Mercon today, zero synthetic PS fluid in that section, and the only synthetic ATF I saw was for Chrysler brand vehicles (ATF+ I think it was).

Anyhow, I'm on my 2nd time through completely draining and filling the system and bleeding per directions. Pump is topped off, I have the front end in the air, and I turn the wheel lock to lock. Some bubbled pop up, fluid level goes down, so I top it off again. After a few more cycles of the steering from side to side, I notice a puddle of fluid on the ground - seems it overflowed.

So I get the wife to turn the wheel for me while I watch. As she is turning the wheel, still front end raised, engine off, the fluid level in the pump rises. If she goes fast, it rises enough to overflow. Then it drops back down again. I have her go right from one direction to another and the fluid peaks near the top of the pump right as the steering hits the stops and then as the steering is turned the other direction the fluid level goes back down then peaks again by the time it reaches the other stop.

So I had her start the engine and as soon as she did, the fluid level which was correct cold dropped way down low and I could see it start foaming instantly.

I don't know what else to check with this. The lines are new and are tight. Pump and gear are new. Fluid I'm using now is a Lucas brand that says it won't foam.

Why is the fluid level still going up when the wheel is turned, and why do I suddenly lose fluid volume with the engine running which causes it to foam?

Right now trying to drive it feels like manual steering. Worse, sometimes it actually feels like its fighting me.

Any input appreciated.

 

the level is dropping because the air pocket is compressing. If you make a cap for the ps pump that you can attach a vacuum source to, then cycle the steering with the system under vacuum it should get the air out. The idea is to expand the air pocket so most of it will be purged out, then when you remove the vacuum the air pocket shrinks back down and is too small to hurt or it works its way out. I have had 1-2 systems over the years I had to do this to and it worked well

 

I've used this fluid extractor to bleed the system with good results. ToolWEB -- Your Online Source for Auto Tools

 

The engine shouldn't be running when you bleed the system, both tires should be off the ground. Grab a wheel and push it back and fourth slowly till there are no more bubbles comming up. Then start it, if you see bubbles then there is probably a leak somewhere.