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Can't speak to the PSC pump. I went the LMM route mainly because it was on Amazon prime at a good price and a new unit.

I was having bad issues when towing of loosing PS and brakes when turning sharp especially when going down hill. Seemed like the heavy braking combined with turning was causing something in the system to fail.

A few years ago I had replaced the broken stock pump with a cheapo reman unit. I had bleed several times and tried different fluids.

Couple weeks back installed the LMM pump along with small cooler and used Royal Purple synthetic fluid. Brakes and steering seem to be 100% now. Did quite a bit of towing the last couple weeks with no issues.

I do have 35's and am usually towing 16k.
 
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The only way you would be able to tell the difference is to the LMM pump, which is a TC style Saganaw Power Steering pump to someone who can pressure test the pumps back to back with a SP 1404. GM doesn't list what the output gallons per minute nor the highest PSI that the units produce. When I had Howe Power Steering rebuilt my original power steering pump, they have a dyno that they run the pump at for one hour at 1800 rpm prior to the rebuilt and after to tell me what the differences are.
 

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I'm bringing this thread back up because there was some great information thrown around in here and I hope it helps someone else in the future.

I wanted to update that I am able to turn lock to lock while stopped on asphalt, such as in a drive thru or in a parking lot. I see that over a year ago I said I was unable to do this, and nothing significant has changed since then other than time. This leads me to believe that I had air in my fluid/lines that has slowly bled out and now I'm fully purged.

My setup is:
AC Delco fluid (about 10k miles on it)
Red Head gearbox (about 15k miles on it now)
Stock LBZ pump
Stock center link
Kryptonite tie rods/tie rod ends
Moog pitman arm
Moog idler arm
Kryptonite idler arm pivot
Kryptonite weld in idler arm brace
PISK brace on idler side only

Other relevant info;
35" tires
Cognito 4-6 NTBD kit
Kryptonite upper/lower BJ's
 

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With that being said, I do also have a question.

This thread was originally to discuss the PSC pump vs the LMM pump, but what about both vs the stock LBZ pump? Is it fairly universally agree'd that either will provide better performance than the LBZ stock pump?

I know the old saying if it ain't broke don't fix it, but I still wonder if I'd have even better steering and braking if I went with the LMM pump.
 

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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
So, is this "26025709 Union Fitting" a flow control orifice? I've seen it mentioned in the TSB on swapping the 670 steering box for the 680 but no description given to what this part does.

Does the 680 box need the flow into it restricted or opened up to provide proper "feel" at the steering wheel and not be too light or heavy steering?
 

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So, is this "26025709 Union Fitting" a flow control orifice? I've seen it mentioned in the TSB on swapping the 670 steering box for the 680 but no description given to what this part does.

Does the 680 box need the flow into it restricted or opened up to provide proper "feel" at the steering wheel and not be too light or heavy steering?
I thought 670 and 680 boxes were only relevant in half tons?
 

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I'll take a stock box before a redhead, hands down.
 

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So, is this "26025709 Union Fitting" a flow control orifice?
Yes, makes for easier steering.just depends what union is put in you will be able to turn your steering wheel with one pinky. What most people do when they put on bigger tires or run in the sand dunes around here they cheep out and just drill the Union out a little more.
(033) we call this a Union at work.STEERING PUMP ASM
(002) there's a higher pressure valve that you can buy.
Union makes for easyier steering.
Valve gives you more pressure for hard steering.
Unions have a letter stamp on them. That letter represents flow rate. W= 3.1- 3.4 GPM etc...
 

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Yes, makes for easier steering.just depends what union is put in you will be able to turn your steering wheel with one pinky. What most people do when they put on bigger tires or run in the sand dunes around here they cheep out and just drill the Union out a little more.
(033) we call this a Union at work.STEERING PUMP ASM
(002) there's a higher pressure valve that you can buy.
Union makes for easyier steering.
Valve gives you more pressure for hard steering.
Unions have a letter stamp on them. That letter represents flow rate. W= 3.1- 3.4 GPM etc...
Can you tell more about the valve, 002 in the diagram, for more pressure? I already have pinky steering but more pressure for tighter or Offroad situations would be nice
 

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Can you tell more about the valve, 002 in the diagram, for more pressure? I already have pinky steering but more pressure for tighter or Offroad situations would be nice
The valve that's in my truck is GM part 19122196 1350-1450 PSI
GM Part 26095470 valve. This is a high pressure valve.

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers - keywords bind booster brake hard hydraulic low no noise oil power slow speed steer trailer #PIT3386A - (Apr 28, 2005)

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers 2002-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2002-2005 Chevrolet Avalanche
1999-2005 Express, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Savana, Yukon, Yukon Denali, Yukon XL
2003-2005 Hummer H2
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Condition/Concern:

Some customers may comment on a lack of steering assist or shudder during parking lot type maneuvers.
Recommendation/Instructions:

Please follow normal diagnostics in eSI for this condition. If the customer situation warrants a repair, replace the current pressure control valve with P/N 26095470, available from GMSPO. This valve will provide additional steering assist during parking lot type maneuvers. If this concern occurs when stopped or at very slow speeds with brakes applied, please reference PIT3310.
Please follow this diagnosis 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.
 

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Dumb question but what's the difference with getting the GM Part No.20756713 pump (the entire pump) for 07.5 and newer trucks vs getting the valve and union parts that Rvn4me is talking about? Does that newer pump for the 07.5 have these parts in it already?

Thanks

LA DMAX
 

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The newer pump has a different number of vanes inside (IIRC, 12 vs 14, I forget which is which), so it seems to work better. Don't know if it has this high pressure valve.
 

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I'll throw another curve ball out there 2016 MY:


My 2016 has a noticeably easier feel/stronger assist than my 2012. What changed there?


I'll also note that I have a hiss in the hydroboost at idle when no load is applied that may be part of an underlying issue. Sounds like I have a small transistor radio under the dash tuned off frequency.




Some say works great, others say sucks, but need to verify a couple of key variables.


1) Tire psi
2) wheel offset
3) Tire width and compound


Width and psi affect contact pattern and resistance greatly.


P.S. My 2002 works fine with 265's. With 285's of a softer compound it gives me grief. Neither my 2005 or 2007 had issues other than the 2005 being noisy when hot. Both had 265 Michelins (hard rubber)
 

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The valve that's in my truck is GM part 19122196 1350-1450 PSI
GM Part 26095470 valve. This is a high pressure valve.

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers - keywords bind booster brake hard hydraulic low no noise oil power slow speed steer trailer #PIT3386A - (Apr 28, 2005)

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers 2002-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2002-2005 Chevrolet Avalanche
1999-2005 Express, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Savana, Yukon, Yukon Denali, Yukon XL
2003-2005 Hummer H2
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Condition/Concern:

Some customers may comment on a lack of steering assist or shudder during parking lot type maneuvers.
Recommendation/Instructions:

Please follow normal diagnostics in eSI for this condition. If the customer situation warrants a repair, replace the current pressure control valve with P/N 26095470, available from GMSPO. This valve will provide additional steering assist during parking lot type maneuvers. If this concern occurs when stopped or at very slow speeds with brakes applied, please reference PIT3310.
Please follow this diagnosis 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.
Interesting. But isn't that bulletin a snippet of the whole thing, I thought the whole bulletin as a part where it says for 2500-3500 do nothing, but for 1500 check if it's 670/680 box and/or replace valve?

I don't like to just throw random parts into my truck without fully understanding lol so that's why I'm asking so many questions.

I guess I'm trying to figure out if the valve is simply a valve GM makes and happens to fit our truck pump, or if this is an actual part GM intended to remedy the pump on 2500-3500 trucks.
Dumb question but what's the difference with getting the GM Part No.20756713 pump (the entire pump) for 07.5 and newer trucks vs getting the valve and union parts that Rvn4me is talking about? Does that newer pump for the 07.5 have these parts in it already?

Thanks

LA DMAX
I also have a similar question that I posed on the last page.

I was wondering if it was universally agreed that the LMM pump was better than the LBZ/LLY/LB7 and worth swapping out regardless. If the answer is yes, swap it out, then the question also is would the LMM pump benefit from this valve swap as well?
 

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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
The valve that's in my truck is GM part 19122196 1350-1450 PSI
GM Part 26095470 valve. This is a high pressure valve.

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers - keywords bind booster brake hard hydraulic low no noise oil power slow speed steer trailer #PIT3386A - (Apr 28, 2005)

Lack of Steering Assist or Shudder During Parking Lot Type Maneuvers 2002-2005 Cadillac Escalade, Escalade ESV, Escalade EXT
2002-2005 Chevrolet Avalanche
1999-2005 Express, Silverado, Suburban, Tahoe
1999-2005 GMC Sierra, Savana, Yukon, Yukon Denali, Yukon XL
2003-2005 Hummer H2
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in the PI.
Condition/Concern:

Some customers may comment on a lack of steering assist or shudder during parking lot type maneuvers.
Recommendation/Instructions:

Please follow normal diagnostics in eSI for this condition. If the customer situation warrants a repair, replace the current pressure control valve with P/N 26095470, available from GMSPO. This valve will provide additional steering assist during parking lot type maneuvers. If this concern occurs when stopped or at very slow speeds with brakes applied, please reference PIT3310.
Please follow this diagnosis 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.
I think I answered my own question.

It looks like you and RamblinRodney both posted PIT#3386, but his was 3386D and yours was 3386A.

Either way, they both suggest replacing the valve and it seems to apply to 2500-3500 as well as 1500.


Now my only remaining question is, should I:
Try the valve
Switch to LMM pump
Switch to LMM pump and try valve
ORRR, given Kennedy's new info, maybe switch to the LML pump!?!
 

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ORRR, given Kennedy's new info, maybe switch to the LML pump!?!
2011-2017 Takes a different pump and mounting bracket. There is no way to incorporate GM part # 20756713 pump into a 2001-2010. Not in less you have a few grand and own a machine shop.
 

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2011-2017 Takes a different pump and mounting bracket. There is no way to incorporate GM part # 20756713 pump into a 2001-2010. Not in less you have a few grand and own a machine shop.
Ah I see.

What do you think of a 2001-2007 pump with the updated pressure valve versus a stock LMM pump? Which is better?
 

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Yes, makes for easier steering.just depends what union is put in you will be able to turn your steering wheel with one pinky. What most people do when they put on bigger tires or run in the sand dunes around here they cheep out and just drill the Union out a little more.
(033) we call this a Union at work.STEERING PUMP ASM
(002) there's a higher pressure valve that you can buy.
Union makes for easyier steering.
Valve gives you more pressure for hard steering.
Unions have a letter stamp on them. That letter represents flow rate. W= 3.1- 3.4 GPM etc...
Thank you very much for explaining that.
 

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I currently have a random, remanufactured boost pump in my truck (sold to me as correct replacement for my 2004.5 LLY 4wd Crew Cab). It's providing unsatisfactory brake and steering performance. If there is a particular valve that I can replace in the back of the pump, what part number is it? I'd basically prefer as much boost as is safe and reasonable.
 
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