PS pump whine when autocrossing. '68 pump, '86 monte ss box

[68Malibu383]

Hey all,

I have a '68 Chevelle with a late 80's Monte Carlo SS steering box. Been running that combo for about 20 years using the Lee Mfg fitting adapters and a stock reman '68 PS pump.

During normal driving, everything works fine. When autocrossing, the pump wines and steering becomes jerky. Last time this happened, fluid spewed out from the PS pump cap and sprayed my brake rotor.

The first time I autocrossed the car, this happened and Lee Mfg had me remove a restriction at a fitting on the pump or steering box. Something about the fluid not returning fast enough to the pump or fluid leaving too fast?

I've since changed both the box and pump and cannot recall what I need to do to fix this. I've called Lee Mfg and we played phone tag for a while and now when I call (several weeks ago at this point), the phone line is dead.

Anyone know where this restriction is?

[David Pozzi]

What steering box do you have? 12.7 to 1?
In general, increasing the restriction diameter of the pump pressure outlet fitting will increase flow through the box, & should only be done if you lose assist when turning the wheel quickly. The downside of a larger restriction is, the higher return flow from the box back to the pump can create swirling and bubbles in the reservoir, also more heat. Once you have bubbles, the pump makes noise and can have a pressure drop.

There is a check valve flapper in the steering box inlet, sometimes people remove that to help flow but I doubt it helps to any significant degree.
Take note of where the return hose nipple is pointing. It should aim the return flow at the pump body inside the reservoir, NOT up at the filler cap or shooting flow above the level of the oil inside the reservoir.

Lee Manufacturing is out of business. I heard an ex-employee started another business in the area but don't have any details.

[68Malibu383]

Yes, it is the 12.7 box. I did partially/intermittently lose steering assist in rapid turns. I do have a factory 90s F body cooler in place. I will take a look at how the return nipple points. Thanks for your suggestions.

[David Pozzi]

Stock hoses, or AN fittings?

[rentedmule]

Aren't these just symptoms of overheating PS fluid? Maybe you need a larger cooler? This occasionally happens to my truck (running the same 12.7:1 box as the Monte) and often on my firebird when I run tight auto-X courses. I just installed a PS fluid cooler on the bird but haven't had a chance to see if it fixed the problem yet.

[1BADBET]

Is it the same whine sound as a power steering belt being loose? I wonder if the belt is slipping and that's what is causing the noise and the intermittent loss of assist. I don't know your set up but a heavy car with big tires might be too much for the set up your running.

[anthonys 69]

I agree with Tyson you probable need a big or better power steering cooler. also check for bubbles in the reservoir if there are bubbles you need to check all the low pressure fittings and connections, on the return side a slightly pinched ''o'' ring on a fitting will allow the pump to suck air in the system and create bubbles. if a pinched 'o'' ring is on the high side it would leak, good luck

[68Malibu383]

Stock hoses, or AN fittings?

All stock.

[68Malibu383]

Aren't these just symptoms of overheating PS fluid? Maybe you need a larger cooler? This occasionally happens to my truck (running the same 12.7:1 box as the Monte) and often on my firebird when I run tight auto-X courses. I just installed a PS fluid cooler on the bird but haven't had a chance to see if it fixed the problem yet.

Maybe. The problem does not surface immediately but on the second run and beyond in each case. Post back after you test the bird.

The noise is not belt slip, it is lack of fluid. Dry/low pump whine as I hear late 80's/mid 90's Fords in parking lots quite often.

Thanks for all suggestions. I'll post back when I get it solved.

[1BADBET]

Would where the cooler is mounted make a difference? I mean if the cooler was higher than the pump resivior the cooler and lines wouldn't fill up all the way right?.... Could be why it's not returning fast enough, because the system isn't full..... Just thinking aloud I'm not sure if that makes sense or if it works that way.

[Rod]

picture of your engine compartment please.....every one here is right, its several factors, 1) you need a larger cooler the factory one is good for daily but not for a real autocross 2) the cooler should be mounted lower than the reservoir 3) the return flow should be at or below the the level of the oil inside the reservoir 4) if you autocross change your fluid at the same time you change your oil(everything in there is metal to metal) 5) add a power steering filter 6) change fluid brands....I used a high zooting expensive fluid and my pump whined like a baby after doing everything right, I changed to a cheaper prestone brand and it was smooth like butter!

[hotrodalex]

I'm running the same setup without a cooler and haven't had much trouble. What tires are you running up front? Also, how hot was it outside when this happened?

I use Prestone fluid, keep the belt pretty tight, and usually overfill the reservoir a bit. Never lose assist and usually doesn't whine or complain. To fix the fluid splashing in the engine bay, fold up a thick paper towel and zip tie it on top of the pump.

[rentedmule]

To fix the fluid splashing in the engine bay, fold up a thick paper towel and zip tie it on top of the pump.

On mine the fluid was coming out so fast that it soaked and then squirted right through a doubled-up piece of microfiber cloth I had wrapped around the reservoir cap and held in place with an elastic. I have an auto-x tonight, I'll report back on whether or not the fluid cooler fixed the issue.

[rentedmule]

I was totally wrong, the cooler did nothing for me. The reservoir was pressurized and fluid was weeping out the cap even after the 30 minute highway drive to the event. I taped a towel around the reservoir lid and it was soaked after 5 laps - a bit of fluid was even squirting out the hose connection going into the bottom of the reservoir.

[David Pozzi]

The stock cap has a Vernay valve in it to hold in some pressure.
Any sudden changes in hose diameter can cause foaming but the type of fluid has a lot do with it.
I'd like to know the diameter of the restriction in your pump outlet fitting, it should be .140" or less. Too much flow makes it tough to control foaming. I would try a different brand of fluid. I've used the valvoline PS fluid a lot mostly because it's easily available.

[68Malibu383]

I'm running the same setup without a cooler and haven't had much trouble. What tires are you running up front? Also, how hot was it outside when this happened?

I have 255 45 17s up front. The outside temperature was in the mid 70s.

[David Pozzi]

Do you have a Hydraboost?
Check over your hoses and look for obstructions or anything that would pinch down the flow. Any sudden changes in diameter can cause foaming. A loose fitting can also suck in air when flow is high. Try a different fluid, try a different cap. When you autocross, don't go to full lock and hold it. That's the absolute worst thing you can do.

[68Malibu383]

Do you have a Hydraboost?
Check over your hoses and look for obstructions or anything that would pinch down the flow. Any sudden changes in diameter can cause foaming. A loose fitting can also suck in air when flow is high. Try a different fluid, try a different cap. When you autocross, don't go to full lock and hold it. That's the absolute worst thing you can do.

No hyrdaboost. I'll check all of those things, change caps and fluids. I know full lock generates a ton of heat very quickly. One turn was extremely tight and I did go full lock briefly - need 4 wheel steering.

[rentedmule]

Update on mine - I did a full fluid flush (it looked nasty and was probably original to the car), adjusted some of the cooler hoses to make sure there were no kinks or unnecessary tight bends, and set the fluid level in the reservoir a bit below the max fill line. That seemed to cure the problems. I've done half a dozen events since then with nothing more than some minor weeping out of the reservoir cap.

[68Malibu383]

Update on mine - I did a full fluid flush (it looked nasty and was probably original to the car), adjusted some of the cooler hoses to make sure there were no kinks or unnecessary tight bends, and set the fluid level in the reservoir a bit below the max fill line. That seemed to cure the problems. I've done half a dozen events since then with nothing more than some minor weeping out of the reservoir cap.

Thanks for the update. I'm getting ready to install a very large cooler on mine. My fluid was new when the problem occurred so I'm hoping the cooler will help. When you say you willed a bit below the max line, was that with fluid cold or hot? Somebody said they actually overfill theirs and that provided some benefit. Just wondering if you filled it to the "max hot line" while fluid was cold. I'd think that would cause a problem, but again, somebody had luck overfilling theirs.

[rentedmule]

I filled to a bit below the max hot line after getting the car up to normal operating temperature driving around town. I figured it would allow a bit more space in the reservoir if the fluid expanded further after hard driving. My problem on the firebird was mainly the fluid blowing out of the valve on the cap though. Extra fluid volume may keep the temperature from spiking so high and eliminate the whine associated with overheating.