Foaming power steering pump. Still.....

[Wagnerwerks]

I've been dealing with this since last year when it was cold. My power steering pump foams whenever the the temp drops below 50 degrees. I just put a new pump on and all new return lines. There are no obvious leaks or weeping. I think it's cavitation but I don't know what to do about it. Tried regular ATF first when it started, and now it's been flushed with amsoil. The only thing I can come up with is there must be a leak in my steering box. Make sense? If I let it warm up before moving, it usually doesn't foam, but it will still do it randomly.

Is there a thinner fluid I should use? I'm at a loss and I want this working right for winter.

 

[elhombre]

Hose claps will leak when they are cold. I know my radiator clamps do this when it gets really cold. Try getting some small radiator clamps and tighten them down real tight on the big hose connections from the reservior down to the pump. See if that helps. Or if you already replaced the clamps with new ones......Nevermind

 

[Wagnerwerks]

Any advice is appreciated. The clamps have mostly been replaced, but I can't remember if I got all the spring clamps. I'll check that.

 

[Pin_Head]

Check the fluid level with the engine off and idling. If the level drops significantly when idling, then there is air in the system. When bubbles recirculate through the pump, you get foam. Also make sure that the suction side hose is not obstructed or collapsing.

50 degrees is not a particularly low temperature, so I can't see that being a factor other than coincidence.

 

[Crashdix]

^^agree - 50 degrees shouldn't affect anything that would cause the foaming - air is getting in the system from somewhere - had a similar issue and found that the bottom hose on ps pump was not reassembled "just right". I would start there - double check all hoses and fluid level and bleed it well with front tires off the ground - left to right all the way to the stops - good luck I'm sure you'll get it fixed

 

[CruiseOrlando]

There is a procedure for bleeding the PS system. I don't have it handy, but if no one else responds with it by the time I get home tonight I'll dig it out and share.

 

[Squash]

Lift the front end, with engine off cycle steering left to right and rt to lt, this should force the bubbles out eventually, repeat as required add fluid as required.

 

[Wagnerwerks]

Ok... I need to add more info.

I have been driving this thing for 4500 miles since I replace the pump and lines. I know 50 isn't cold, but it is ONLY doing it from 50 down. If I let it sit and warm up before driving, it usually is fine. I am very sure that there was no air in it before this morning and its been from pa to new york to delaware beach this summer with no issues. The fluid reads right on while running.

I did do a smog pump delete with the normally recommend belt (can't recall the number right now) and the pump is slightly tilted to the pass side. Not a lot, but not straight up and down.

When I bought the truck I did a trans with new huge cooler, knuckles, engine tuneup with oil pan, and a ton more, but nothing to the steering. The issue came up of course while on a trip when the temps dropped.

I've tried adding extra fluid, bled the system fifty times, and two pumps. At this point, I think the original pump was fine and this other issue was always the problem. I just don't know what else to do. It's my winter car and it starting to get cold.....

 

[Wagnerwerks]

Forgot to say thanks... I really do appreciate all the advice. I'm starting to think there is a seal shrinking in the cold and when it warms slightly, it seals right up..... But I would expect it to leak.

 

[Pin_Head]

So I guess there is no problem then?

Usually when your PS fluid is foamy:
1. The pump makes a lot of noise.
2. Your PS is messed up with puslation or loss of boost.

 

[Wagnerwerks]

There's definitely a problem. When it foams when it's cold, both of those things happen. I was in no way trying to discount the other posts with helpful info. I'm sorry if I came across that way.

Thank you for all posts. I'm just at a loss.

 

[Pin_Head]

It wasn't clear if there was a problem from your latest updates.

It there is foam and the system is not under filled, then it is sucking air into the intake. Try replacing the low pressure hose. It is cheap.

 

[Offroads4x4]

Doesn't the P/S have an inline filter as well?

You could have a seal giving you some grief like you said. I would look at putting a P/S sealer product like Lucas Oil has if that's the case.

Some people have used compression clamps on older hoses but that's most likely overkill for a P/S I would think.

To bump air out you turn the steering all the way to one side and hold, release, hold, release, then do the other side. Keep your P/S cap loose while you do this so there is little back pressure.

Just some thoughts

 

[Wagnerwerks]

Thank you again for the suggestions. I'll keep trying them and post up results.


The return lines are all new with high quality hose and all new screw clamps. I'm not usually a fan of stop leaks, but I like Lucus stuff and this is getting close to that point of lack of other options.

 

[Wagnerwerks]

Doesn't the P/S have an inline filter as well?
Just some thoughts

Anyone know about that for sure? I don't remember seeing one. Great idea though.... I'll look into it.

 

[Offroads4x4]

There should be a P/S filter in line. I just looked it up and they show a P/S filter at NAPA and Auto Zone parts.

 

[Wagnerwerks]

Roger that... I'll check in the morning.


Thanks for the legwork!

 

[Tools R Us]

I prefer the factory spring type clamps, they are constant tension, but the screw type should work.

For a leak to cause foaming, most times it has to be on the suction side, between the reservoir and pump. On the 3FE, the reservoir is mounted on the pump, sealed by an o-ring. If it were sucking air, would expect it to leak fluid when the motor is off.

There is no external filter on the system, the reservoir has a screen in it. Adding one, IMHO, is not recommended, they add restriction and hydraulic systems are all about flow. If your worried about contaminants, simply change/flush the system more often.

It is possible/likely for foaming to happen without a leak, the vapor bubbles are created in the pump by cavitation. This is most often caused by a restriction in the suction side and/or fluid type/viscosity. This is what your problem sounds like, especially because it is only happening when cold, when the fluid is thicker.

Toyota sees them as "not serviceable" buy a new reservoir, but, it is possible to get to the screen. Remove the reservoir, pry the tabs open that hold the top plate on, remove it, inspect/clean the screen, put the top back on and recrimp the tabs. I use a bit of RTV in the gasket. In lots of years of working on them, have only seen a couple that were dirty, clogged enough to cause a problem.

I would not use any additives in the system, they are not needed and long term likely to cause more problems than they solve. ATF is good fluid, for an auto trans. Often it works well enough, but it's not the highest performing fluid for a purely hydraulic system. ATF has lots of additives to deal with the clutches, etc, a power steering system has none of that, so they would be contaminants in this application.

Maybe try a different fluid? I have had great results from running light hydraulic fluid (Mobil DTE light) in Toyota systems, in my experience, a higher performing fluid for the application. If you don't have a ready supply, the power steering fluid listed for earlier GM's is basically the same stuff, works well. It is true that ATF is spec as replacement fluid, but they came from the factory with hydraulic fluid.

 

[86tuning]

+1 on checking the screen. I've seen more than one blocked screen on toyotas. Whining when cold is the first symptom.

 

[Tools R Us]

This is what the inside of the reservoir looks like on a 1FZ.