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Power steering needs some help???

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Old 02-13-2012, 01:48 AM   #21
killerbeeDH
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Jim, some questions for you.

GM has a real problem with inadequate fluid flow on some platforms. Heavy engines, bigger tires, aftermarket wheel offset, etc illuminates the problem, which is most noticeable at idle parking scenarios where brakes (hydroboost) robs flow further. In these scenarios, steering assist suffers unless engine rpm is increased during the maneuver.



1. Is there a reason to expect flow to increase at idle rpm with a modified flow fitting?
2. What is the function of the larger hole on the wall of the fitting, closest to the flow control valve?
3. Can the large flow control spring lose rate over time, creating recirculation (bypass) even at idle/low flow condition?

I have examined a couple of reman pumps and noticed that the fit of the flow control valve in the port is not very tight, there is obvious play.

4. Can blowby recirculation be a factor, particularly in reman pumps?

Michael
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Old 02-13-2012, 08:42 AM   #22
Jim Shea
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Quote:
Originally Posted by killerbeeDH View Post
Jim, some questions for you.

GM has a real problem with inadequate fluid flow on some platforms. Heavy engines, bigger tires, aftermarket wheel offset, etc illuminates the problem, which is most noticeable at idle parking scenarios where brakes (hydroboost) robs flow further. In these scenarios, steering assist suffers unless engine rpm is increased during the maneuver.



1. Is there a reason to expect flow to increase at idle rpm with a modified flow fitting?
2. What is the function of the larger hole on the wall of the fitting, closest to the flow control valve?
3. Can the large flow control spring lose rate over time, creating recirculation (bypass) even at idle/low flow condition?

I have examined a couple of reman pumps and noticed that the fit of the flow control valve in the port is not very tight, there is obvious play.

4. Can blowby recirculation be a factor, particularly in reman pumps?

Michael
Michael,
Here are my answers to the best of my knowledge:
1. Idle flow will not increase with larger outlet fitting throat diameters. At idle, the flow is controlled by the displacement of the pump itself. A larger rise cam is needed to increase the flow at idle.

2. I think the hole on the end of the discharge fitting is to prevent the flow control valve from restricting flow when it is hard against the end of the fitting.

3a. I am not aware of flow control valve springs losing compression load. But anything is possible.

3b. The fit of the flow control valve to the pump bore is very critical. Excessive clearance would translate to increased blow-by and loss of flow under all conditions. I know that Saginaw held the pump bore inside diameter and the flow control valve outside diameter extremely close. I don't recall the exact clearance numbers. We did competitive analysis of Toyota pumps and found that they had to zone their parts (measure and match) in order to obtain the tight clearances that Saginaw held as produced.

Jim
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Old 04-27-2013, 12:49 AM   #23
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I am thinking of getting an old astro van pump any specific years or all they all the same
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Old 06-13-2013, 03:35 PM   #24
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My power steering works most of the time. Sometimes tho, at slower speeds I have to really rev the engine to get it to be power steering again. It just goes non power...should I check the valve, part no. 6, inside the pump?
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Old 06-30-2013, 08:10 PM   #25
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I just tried this yesterday. A 1/8 inch (0.125") drill bit was a sloppy fit in the passageway, and a 9/64" (0.141) would not fit. So I guess the origional orifice was something like 0.130". Drilled it out with the 9/64, cleaned and deburred it, and replaced it. So I increased the cross sectional area of the orifice by maybe 17%. Hope it's not too much.
Test drove at about 9:30 PM last night.
Nice.
I like it.
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Old 06-30-2013, 08:13 PM   #26
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Quote:
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One thing about opening the throat of the discharge fitting is that more flow also translates to higher system fluid temperatures. More flow out of the pump causes higher back pressures down stream and the pump has to work a bit harder. This will cause somewhat higher system temperatures. I'm not saying that you will need a cooler but just be aware of this drawback.

Jim
Lets say we measure the temps. At what temp would a cooler be required? How hot is too hot?
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Old 07-10-2013, 07:49 PM   #27
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Quote:
Originally Posted by gcusmano74 View Post
Lets say we measure the temps. At what temp would a cooler be required? How hot is too hot?
I would view it as being similar to an auto trans. Many new cars and truck come with coolers now a days. My rule of thumb is, you need over 200* to steam out moister but over 250* rubber and seals start getting soft.

Hope that helps.
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Old 08-03-2013, 05:29 PM   #28
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Old 11-22-2013, 12:17 PM   #29
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I sure have appreciated the Borgenson Co. power steering set-up. I had to rob the Piggy bank, But it is the Best money I've spent in a long time. Have a happy Thanksgiving. Gene
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Old 08-13-2014, 02:40 AM   #30
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This might be an odd ball question but is there anyway to boost the power steering on these old vettes? Mine is an 82 and because of authritis I'm starting to have a had time with parking. I thought there might be a way to bump up the hydralic pressure but I can't find anything on line.
I had a similar problem. Someone told me about the stuff so I tried it. I sucked all the fluid I could out with a fluid pump. I then added 16 oz. of Lucas Power Steering Conditioner and Stop Leak. I then finished filling the reservoir up with fresh power steering fluid. It made a world of difference. It was a cheap fix, and that was about 4 years ago.
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Old 04-25-2015, 01:49 PM   #31
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I had a similar problem. Someone told me about the stuff so I tried it. I sucked all the fluid I could out with a fluid pump. I then added 16 oz. of Lucas Power Steering Conditioner and Stop Leak. I then finished filling the reservoir up with fresh power steering fluid. It made a world of difference. It was a cheap fix, and that was about 4 years ago.
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Old 08-22-2015, 07:41 AM   #32
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Quote:
Originally Posted by Jim Shea View Post
One thing about opening the throat of the discharge fitting is that more flow also translates to higher system fluid temperatures. More flow out of the pump causes higher back pressures down stream and the pump has to work a bit harder. This will cause somewhat higher system temperatures. I'm not saying that you will need a cooler but just be aware of this drawback.

Jim
you can't fill the hole back in if you do not like the way it feels after modification. even if you buy another to drill. you should have orig part in a box with all the other orig parts.
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Old 01-13-2016, 12:34 AM   #33
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I went a different route to increasing the power steering output. I tried replacing the power valve and pump, wheel alignments, and played with the pump valve modification as listed in the above post without any luck.

I replaced the springs in the power valve. The spool in the power valve must move to provide the assisted power steering. By replacing with a weaker/lighter set of springs the spool will move side to side with less effort applied. Look at how the power valve works and you will see what I'm talking about. One must use caution to not install to weak a spring to provide to much assist. I made this modification around 20-25 years ago and can't tell you what springs I used.

This made the 74 vette a different car. I actually hated driving the car at first but loved the lines. After the power valve modification I then loved driving the car. Much lighter feeling and didn't drive like a tank around town.
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Old 02-27-2016, 02:18 PM   #34
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Does the Borgeson offer 'easier' steering, or just better steering?

After the mod, will slow parking lot steering be less effortless?

Thanks
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Old 07-21-2016, 09:20 PM   #35
jim in oregon
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Originally Posted by damoroso View Post
I guess the first question is, are you sure your steering is working properly now? These aren't designed to have so much assist that you can turn the wheel with a finger, but they aren't that tight if things are working properly. If you have a stuck flow control valve, faulty control vavle or some other failure, that's an entirely different issue. Then there's the problem that these systems were designed to work with a specific pressure, if you go over that, I'd think you run the risk of blowing seals or hoses.

That being said, you could always swap to a Borgeson steering box or a rack system if you need more power assist.
I guess the first question is, are you sure your steering is working properly now?.."
Same here and before making any modification..Check the power steering fluid AND see that the level is proper on the little dipstick based on TEMPERATURE..COLD will be lower level than hot..Also check the belt,,
yes it's not easy to be older..but check the simple stuff first..IF you have anyone in a local club who has a similar system..have them try your steering..and you try theirs...Jim
"
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Old 06-17-2017, 10:54 AM   #36
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I still don't fully understand that if Hydroboost is added does it change the dynamics sufficiently enough to require a PS pump upgrade? A low speeds after the accumulator is drained braking is dangerous, when parking both braking and steering is nearly impossible. I am running 245 tires up front. Mind you the issue seems to have gotten worse, thinking the pump is fading or I just NEED more flow. I see that Corvette Pacifica offers both an OEM and a Saginaw pump, with the later being new and cheaper! I know I can adjust the pressure output, but I don't think is this the way forward.

Any ideas? ... I want to take this old girl to the track someday!
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Old 06-18-2017, 05:29 PM   #37
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Originally Posted by carbster09 View Post
I still don't fully understand that if Hydroboost is added does it change the dynamics sufficiently enough to require a PS pump upgrade? A low speeds after the accumulator is drained braking is dangerous, when parking both braking and steering is nearly impossible. I am running 245 tires up front. Mind you the issue seems to have gotten worse, thinking the pump is fading or I just NEED more flow. I see that Corvette Pacifica offers both an OEM and a Saginaw pump, with the later being new and cheaper! I know I can adjust the pressure output, but I don't think is this the way forward.

Any ideas? ... I want to take this old girl to the track someday!
It sounds like you need more flow. Your current pump may have enough capacity, even at low engine rpm, but the control valve may be limiting flow too much. Refer to posts by Jim Shea and Oldboat above.

I increased the flow but I'm still don't have power assist to either brakes or steering. Checking the actuator rod length and projection into the master cylinder is the next thing I'm going to check.
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