Power steering whine and jerk during autocross

[68Malibu383]

I'm back with more info. I posted this problem some time ago, made some changes, and ran in one more autocross and the same problem occurred.

To recap... 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 adapter in steering box and a stock reman '68 PS pump.

During normal driving, everything works fine. When autocrossing, the pump whines and steering becomes jerky. After running fluid spewed out from the PS pump cap.

The assumption was that the fluid was overheating, but it is not. Since my first post, I installed a large transmission cooler (fin not plate) and last time I ran the car, it was 40 degrees outside and the whine began after the first turn (made a hard left, turned wheel back and whine began.) Fluid and reservoir were very cool to the touch after the run but looked aerated. I also installed a different pump cap (restoration "correct" type cap) and changed the fluid (Prestone) and blead the crap out of the system (and drove the car 200 miles to the event the night before, so I don't think any air was left.)

Someone asked the sizes of orifices when I posted originally, so I'll list them below.

Long story short, I'm converting to the AllStar Type II pump system (pn 48242). I'm hoping that will cure the problem but I hate throwing parts at something without knowing the real problem.

If anyone has any ideas, please let me know.

Opening in Pressure Outlet fitting on the pump going to steering box ~.145-.150

Inlet in steering box from pump is ~.340 (this is the opening size of the Lee Mfg adapter so I don't know what is below this)

Return opening in steering box is ~.315

I'm also running an A1 Cardone Magna-Pure Inline Power Steering Filter (pn 20-0012F). I never did take that out of the equation...

[andrewb70]

It would seem to be an easy test to take the filter out of the return loop. I'd try that. Maybe it is not letting the fluid return back to the pump fast enough?

Andrew

[68Malibu383]

That could be it. Already removed the pump to make way for the type ii pump. Read info from KRC that indicates hoses on the return side could collapse, which would explain lack of fluid returning to the reservoir. Who knows. Maybe someone trying to sell stuff? Link: http://static.speedwaymotors.com/pdf/KRC_CastPump.pdf

Would you bother to run a cooler with the type ii pump if it has a remote reservoir for autocross? If so, according to KRC, line should be -10AN, which I assume would include the cooler itself and I've not seen them that large.

[andrewb70]

Running a cooler is never a bad idea. I know the Earl's coolers will accommodate a -10 fitting. I don't know if I've ever seen -10 adapters for the actual steering box. Most people run -6 but yiu have to be careful because some fittings and hoses have smaller I.D.. I have my power steering hoses made at a local hydraulic place and they use industrial hose and fittings that have a true 3/8" I.D.. That's something to consider as well.

Andrew

[68Malibu383]

Running a cooler is never a bad idea. I know the Earl's coolers will accommodate a -10 fitting. I don't know if I've ever seen -10 adapters for the actual steering box. Most people run -6 but yiu have to be careful because some fittings and hoses have smaller I.D.. I have my power steering hoses made at a local hydraulic place and they use industrial hose and fittings that have a true 3/8" I.D.. That's something to consider as well.

Andrew

Thank you Andrew. I'll try running without a cooler first and see what happens. First event is in April...

[garvir]

you might want to contact TURN ONE, 989 759 4201, 7436 east holland road, saginaw, mi. Rami from UMI suspension turn me on to these guys a few years back (turn one does the work for there green monte). i had bought a 500 series steering box from CPP for my 88 monte, never worked right, the first box had a porousity problem in the casting, sprays ps fluid all over the headers, lucky it didn't catch on fire. the second box never worked very well. i sent my box and power steering pump to TURN ONE, worked really good after that. Gary

[68Malibu383]

Thanks, Gary. I'm going to install the AllStar Type II pump system (with their lines/fittings), but bypassing my cooler in the next few weeks and will see what happens.

[UMI Tech]

I'm back with more info. I posted this problem some time ago, made some changes, and ran in one more autocross and the same problem occurred.

To recap... 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 adapter in steering box and a stock reman '68 PS pump.

During normal driving, everything works fine. When autocrossing, the pump whines and steering becomes jerky. After running fluid spewed out from the PS pump cap.

The assumption was that the fluid was overheating, but it is not. Since my first post, I installed a large transmission cooler (fin not plate) and last time I ran the car, it was 40 degrees outside and the whine began after the first turn (made a hard left, turned wheel back and whine began.) Fluid and reservoir were very cool to the touch after the run but looked aerated. I also installed a different pump cap (restoration "correct" type cap) and changed the fluid (Prestone) and blead the crap out of the system (and drove the car 200 miles to the event the night before, so I don't think any air was left.)

Someone asked the sizes of orifices when I posted originally, so I'll list them below.

Long story short, I'm converting to the AllStar Type II pump system (pn 48242). I'm hoping that will cure the problem but I hate throwing parts at something without knowing the real problem.

If anyone has any ideas, please let me know.

Opening in Pressure Outlet fitting on the pump going to steering box ~.145-.150

Inlet in steering box from pump is ~.340 (this is the opening size of the Lee Mfg adapter so I don't know what is below this)

Return opening in steering box is ~.315

I'm also running an A1 Cardone Magna-Pure Inline Power Steering Filter (pn 20-0012F). I never did take that out of the equation...

I would 100% sketch out your steering system and pdf it to [email protected]. He would identify your problem and make a good recommendation.

ramey

[a67]

This is just a SWAG, but is there a check valve at the inlet of the steering box? If so it should be removed. GM added them to some vehicles as a way to reduce the kickback through the box to the driver. I looked for a picture of it but no luck.

The other item would be to make sure to use GM power steering fluid. I had someone else tell me this years ago and they are correct. There is a definite difference in the steering between generic and GM brand P/S fluid.

Bob.

[David Pozzi]

Pressure and return lines should be -6 or 3/8". There is some back pressure on the return line so I wouldn't expect it to collapse. Don't use any fittings with sharp bends. Hose ends with bent "pipe" type fittings are OK. The reservoir to pump inlet line is the one that can collapse or cause aeration. Fluid passing over a sharp edge, especially under suction can cause air bubbles to form. Any sudden change in hose diameter on the pump inlet side of the system is to be avoided. On our system I machined the tank outlet fitting larger to better match the hose fitting ID and put a big radius on the tank side of it. Look at dry sump pump fittings for a similar treatment.

Turn One should be able to match the pump outlet restriction to match your system needs.