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Discussion Starter #1
Looking for information on the differences between the PSC SP1404 High Performance power steering pump, and the newer style OEM Pump. Does anyone know how the pressure or flow rates compare. I'm pretty sure the PSC pump is a 1600 psi pump with a larger ring/rotor to increase volume. And I know the vane count is more on the newer OEM pump according to one of ramblinrodney's posts, but not sure what that equates to in terms of pressure and volume.

My 07 LBZ has 140K on the original pump, and I believe it is getting weak. Would like to try to improve tight manuvering steering, and braking.
 

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That's funny you asked this question, I was just about to! I want to buy the PSC myself as its a brand new unit, I've done a fair amount of research on this topic & noticed some guys with an actual LMM still have issues with it at low speeds/big tires etc. Hopefully someone with an actual PSC pump chimes in here with some real reviews.
 

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Discussion Starter #7
I pulled the trigger and ordered the PSC pump. I should have it the middle of next week.
 

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If you don't mind me asking, who'd ya buy it from? PSC or Amazon?
 

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PAoutdoorsman, thanks for taking the plunge. Looking forward to your review of the PSC pump.
 

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Discussion Starter #10
The new PSC pump arrived today. I decided to do this a little more scientific so I knew exactly what if any advantage the new pump provided. Using a MAC Tools power steering pump tester, I grabbed pressure readings of my aged stock pump as it sits. Here are the numbers I gathered. All while at idle.

Cold start pressure: 400 psi
Pressure after 5 minute idle warm-up: 200 psi
Normal steering left to right: 1250 psi
Turning steering against stop left or right: 1450 psi
Turning steering against stop left or right while holding brake: 1500 psi

Anyone know what spec is?

On to the eye candy...

New Pump


Mac Tools PS22AB Power Steering Tester


Testing Setup


Warm Idle Pressure


Pressure while steering left/right while idling


Pressure when at full turn while pressing brake
 

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Yea man, it doesn't look that bad at all. Maybe just a flush? You do have the PSC so if it were me, I'd be installing it lol
 

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According to this chart I found, my stock pump may not really be all that weak...

Your chart doesn't include Low flow witch the reading comes from your ring/ rotor. 12 vanes in the rotor versus 10 in the older 01 to 07 1.32 Gal. Minute. The high flow reading come from the size of orface in the union/ Fitting GM part 26025709 also in your chart it doesn't include the noise reading witch has tobe lower than 100 I got $25,000 for setting up this noise reading from our new direct drive motors that are used in our test stands. Love sugestion awards. High Frow reading and pressure relief test is at 1500 RPM and Low Flow And noise reading is done at 485 RPM
 

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GM part 26095470 this valve help some but not everyone. I should of grabbed a hand full of valves that were used in Police vehicles.

Lack of Steering Assist or Shudder During Parking Lot Type Manuevers - keywords bind booster hard hydraulic noise #PIT3386D - (07/31/2006)

Models: 2002-2006 Cadillac Escalade Models

2000-2006 Chevrolet Avalanche, Tahoe, Suburban

1999-2007 Chevrolet Silverado Classic

1999-2007 GMC Sierra Classic

2000-2006 GMC Yukon Models

2003-2007 Hummer H2

This PI is being updated to add fix information and models. Please discard PIT3386C.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
Some customers may comment on a lack of steering assist when stopped or during parking lot type maneuvers.

Recommendation/Instructions:
Please follow normal diagnostics in SI for this condition. If the vehicle passes the Power Steering Pressure Test Procedure in SI this may be a normal condition. A lack of steering assist could occur if the brakes are applied and turning the steering wheel with the vehicle stopped or during parking lot type maneuvers. This concern can be aggravated by worn tires, low tire air pressure, low power steering pump pressures, and tires larger than stock size. In some cases, where the power steering pump pressures are at the low end of the specification, replacing the power steering flow control valve with P/N 26095470 may improve the concern. On 1500 models with the 670 gear please following Bulletin 05-02-32-008A, which may increase customer satisfaction.

No further repairs should be attempted as this is a characteristic of the vehicle. Any customer concerns should be referred to the Area Vehicle Manager (AVM) and a Field Product Report should be submitted by following bulletin 02-00-89-002D. When submitting the Field Product Report please advise if the vehicle is equipped with anything other than the stock wheel and tire size, example GM SPO 20 inch Wheels and Tires.

Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
 

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This is a picture of the valve that gets updated #PIT3386D in side this valve there's a ball and colored spring. Depends on the application/valve pressure the string color is changed to get close to desired pressure reading. The final torque on the end of the valve with the screen. That part has lock tite.
This valve is made non other in the valve dept. You could turn the end down to achieve more pressure and add lock tite. What pressure it will be at, who knows.
http://i.imgur.com/do25aGb.jpg
This valve we call pressure relief valve. It is to protect your steering component in case you hit something with your tires/wheel so you don't damage everything on your steering. At a given pressure this valve relieves.
 

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That's some great info!

LA DMAX
 

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Discussion Starter #18
This is a picture of the valve that gets updated #PIT3386D in side this valve there's a ball and colored spring. Depends on the application/valve pressure the string color is changed to get close to desired pressure reading. The final torque on the end of the valve with the screen. That part has lock tite.
This valve is made non other in the valve dept. You could turn the end down to achieve more pressure and add lock tite. What pressure it will be at, who knows.
http://i.imgur.com/do25aGb.jpg
This valve we call pressure relief valve. It is to protect your steering component in case you hit something with your tires/wheel so you don't damage everything on your steering. At a given pressure this valve relieves.
Help me understand this. I always thought the reason for the pressure relief valve was so the pump wasn't sitting against a 1500 psi wall when pressure for steering or braking was not required. Isn't that valve what allows the pump to sit at 200 psi at idle, but instantly provide 1500 psi when the wheel is turned or the brakes depressed?
 

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Discussion Starter #19
Your chart doesn't include Low flow witch the reading comes from your ring/ rotor. 12 vanes in the rotor versus 10 in the older 01 to 07 1.32 Gal. Minute. The high flow reading come from the size of orface in the union/ Fitting GM part 26025709 also in your chart it doesn't include the noise reading witch has tobe lower than 100 I got $25,000 for setting up this noise reading from our new direct drive motors that are used in our test stands. Love sugestion awards. High Frow reading and pressure relief test is at 1500 RPM and Low Flow And noise reading is done at 485 RPM
Yeah, I don't have the equipment needed test flow rate, so I just have the pressure readings to go by. If the pump is capable of building it's intended pressure, the flow should be whatever it was designed to be.

PSC states: "The heart of the 1400 pump is a larger ring and rotor which displaces more fluid per revolution". It seems both pumps aim to increase flow. Is it more advantageous to add vanes to the same size rotor, or increasing the rotor diameter? I'm sure it could be argued either way.
 

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Discussion Starter #20 (Edited)
To continue the experimentation, last night I did another complete fluid flush replacing the Amsoil Power Steering Fluid (which had just shy of 10,000 miles on it) with GM Power Steering Fluid. AD Delco # 10-5073, GM # 19329448.

I felt an incredible difference in the brakes just backing it out of the shop. I've owned this truck since 2010, and never have I had brakes this strong. I took a 30 minute drive just to keep using the brakes, and continue to be impressed by the improvement.

I can't really say the steering felt any different. Honestly it's always felt great while driving. It still wanted to stall out if I turned the wheel while sitting still and holding the brakes on asphalt. However doing this same maneuver on my concrete shop floor, I could turn stop to stop without issue. My camper often has me in this situation getting it into a tight campsite, and this is ideally what I want to improve. I also re-verified all my pressure reading numbers, and they were identical.

It took the dealer parts counter a bit to confirm, but he assured me this was the correct current fluid for my truck. $11.90 per quart.

 
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