Pirate 4x4 banner

Best of : Power steering pump modifications ( pressure and flow )

281K views 149 replies 67 participants last post by  Gozuki 
#1 ·
I have been reading thru a ton of links and forums that cover a wide range of ideas of what works and what doesn’t.

I was going to bring in some quotes but I would rather not rehash those posts.

Instead I would like to see what the general consensus is on these types of modifications.

For example:
I read about users with similar full hydro systems. (orbital valve/cylinder/reservoir)
(A) I find people running an unmodified pump.
(B) And then I read about others that needed to mod the pump for more flow.
(C) And still others found it necessary to run a Vendor pump.

I would like to start with a question that I have not seen answered.

Do all P style pumps run the same internals and the modifications we apply are nothing more than what is done from the factory when the pump is to be used for a particular application?

Next: What are the modifications being performed and what are the expected results? I see a wide range of practices and ideas here.
Can you perform one mod and not affect the other aspects of the pump?

Ex. Can you gain more pressure and not affect flow? Or gain more flow and not affect pressure? Is there a trade off?

What are the limits? (Real world results)
Flow rates
Pressure
Life expectancy (heat)
 
See less See more
#3 ·
I'm also looking forward to the replies. Just cooked my tc pump and am in the process of installing a p pump from a gm with hydroboost. We'll see how that does with the hydro assist.
 
#5 ·
My "spare" pump is a hydraboost GM from a 95(?) 1 ton with 5.7
it is 95% the same as my PSC that I otherwise use....
I keep a pulley on each one, and just swap them out when I have troubles.
I am full hydro with rear steer. I think you will be happy.:p
 
#4 ·
Well I run full hydro, single ended ram with a stock pump and so far have not had any issues other than it leaking out of the cap on angles.. i have just drilled out the outer plug for more flow. Won't have any real world results for atleast a week.

I also am looking forward to learning more on this.
 
#7 ·
Do all P style pumps run the same internals and the modifications we apply are nothing more than what is done from the factory when the pump is to be used for a particular application?
no, there are different P Pumps from Delphi/saganaw

I have only seen 2 different P pump displacement cam packs, both had the same profile one was (if I remember correctly) .200 thicker than a stock chevy truck,car,van,suv (blazer(big or small),land yacht,k10,20,30,C10,20,30, ect...)

what most people modify is the stand by flow/pressure, and system relief pressure (ie. west texas flow mod)
 
#8 ·
Thank you, two different internals.
Is this a key point when choosing a pump for modification?

I think the "modifications" is the gray area for most, myself included.

What works?

This is an old post from the LakeRat:



K guys let me help u out here.

piston 1,2 and 3 are all the same. Piston 4 came out of a different pump. Probably a TC style but i would have to have measurements to be for sure.

But back to the first 3. ok piston 1 looks to be about a 1100-1200 psi piston. #2 a 1050-1100 and #3 around 900-1000 psi.

the only difference in the three is the shims. #1 has locktight on it because the rebuild companys are too cheap to use shims. No matter though because you need to take all of them out anyway.

If your asking what to do then i would take number one piston and heat it up with a propane lighter and then tighten the nut down all the way. That will take the pressure to about 1350 - 1400 which is the factory maximum for a Saginaw power steering system.

Oh and you don't need to drill out anything in the piston the only thing that you might want to drill out is the main fitting but don't do that unless you need fast steering or if you have ram assist. and if you do drill it out. DO NOT DRILL IT LARGER THAT 5/32!!!!!!!!! you might could go larger but do it at your own risk
__________________
Matt Hodges, Owner
West Texas 4Wheel & Offroad
325-651-5010 or thelakerat@aol.com
6305 US Hwy 277 S.
San Angelo, Tx. 76904


Compare to this post:

Saginaw Power Steering pump modifications.....
March 2001


The purpose behind this conversion is to change the high pressure bypass point for the power steering pump fluid. Increasing this pressure point for the fluid will provide increased pump assist during low-speed/high torque manuevers so common in offroad situations. (ie: idleing steep downhills, navigating boulder fields, etc.)

Tools Required:
# 1" socket - 1/2" drive wrench
# 5/8" flare/combo wrench
# fluid catch pan
# 3/8" combo wrench
# bastard file
# 2 #4 machine washers, brass or stainless
Procedure:
With the location of my power steering pump on my 350 conversion, I was able to simply remove the pressure hose from the back of the pmup with the 5/8" flare wrench and then use the 1" socket to remove the large retaining nut/assembly. Depending on your installation, you may need to physically remove the pump. Be sure to catch any fluid that escapes.

With the large nut off, you should then be able to pop the bypass cartridge out. Clamp this cartridge in a vice and use your 3/8" combo wrench to remove the nut. With this nut off, carefully remove the BB, the seat/stem, and the spring. Now take two #4 machine washers and drop these into the opening. Use your file to take about 1/8" off the pin end of the stem (this is precautionary - to prevent the bypass from jamming shut). Drop in the spring, the seat/stem, the BB, and replace the top nut. Reinstall the large spring, the cartridge, and the 1" nut back into your PS pump.
 
#13 ·
it (as far as I have seen) has the same cam pack as a howe/psc/ect.... high volume P pump

it just has a larger reservoir of fluid, I think because of the higher flow requirements of the system, bigger piston box, ect... which is probably why many people here kill pumps, to much flow for the system, to much stand by pressure, not enough reserve to keep fluid cool......


not to get off on a tangent, but I had a med duty international truck with basically a powerstroke, the oil pan held 5 gal of oil, and the engine only revved to 2500rpm, the oil change interval was double that of a ford/powerstroke

:flipoff2:
 
#17 ·
I have been taking stock saginaw pumps and and doing the West Texas mods w/ some success. The best results were with making the return like larger and getting rid of the brass fitting in the steering box return hole and changing the fitting to a barb style as big as you can fit.
 
#21 · (Edited)
subscribed- very interested in this topic as well. I have a couple related questions that I'd like to see addressed.

Can someone talk about ideal flow rates/pressures. Is more always better? My pump is feeding GM hydroboost brakes AND Hydro assist in addition to the stock saginaw p/s box it was intended to run. From my research, it seems that the stock GM hydroboost (which is the first stop on the fluid's journey) will create a bottleneck and limit flow. What are the effects of this bottleneck? Heat and/ or Pressure buildup? Simple reduction in flow rate? I know it can be "Hi-flowed" by companies like Vanco but I wanna spend my $280 on other things if possible.

It seems like it would be helpful to know the ideal flow and pressure for each component in the system: Hydroboost, Steering Box, and Ram Assist. That way a pump or other componenets could be selected or modified to best fit the needs of the system as a whole. It doesn’t make sense to modify and overwork a pump if another component in the system is going to negate that benefit. Anyone got this info?

One last question: When everyone talks about the "P" pumps they are referring to the guts of the common "canned ham" found on most older GMs. Right?

GREAT TOPIC
 
#23 ·
Im a little disapointed that there has not been more responce to this thread. there is so much conflicting information out there on this subject. some people say don't bother modifiying any pump, others say only modifiy p pumps and not tc and some swear there mods work great while some burn pumps up in ten minutes. I guess there are so many system variables that it is hard to find out what works and what doesn't. full hydro vs assist, faster steering vs slower, running high rpms vs lower. I know heat is the biggest concern along with pump cavitation. So if you have these issues addresed is your pump going to perform and last? I don't have much first hand experience in comparing modified pumps to aftermarket ones. I have run stock tc pump on 2.5" double ended ram then modified that pump ( drilled out discharge fitting to 5/32). does the mod work? yes, will it last? time will only tell (only have one run on it). I ran a toyota pump modified the same way for several years and never had a problem. So people with some tried and proven systems please chime in with results.
 
#24 ·
I see what you're saying and I think the reason that there hasn't been more responses is twofold:

1) For the most part, people don;t know how PS pumps work. They aren't like engines where everyone knows what's going on because everyone likes to modifiy them. Very few people have ever actually taken a pump apart and looked inside. And even those who have (Me among them.) don't completely understand what they're looking at.

2) Those who do know and who have opened them up and know how to modify them won't chime in because they are vendors and make money off of knowign what we don't. (Not that there's anythign wrpong with that.)

Normally when I find myself stuck in a situation like this I find the only way to break out of my rut is to just start buying junker components, taking them apart, and learning first-hand. That's what I'm doing right now with automatic transmissions. It is only once one understands exactly how something works that they can begin to modify it to work better.

Therefore what I propose is to essentially start this thread at the beginning. Someone who knows and has the resources post up exploded diagrams of a ps pump and describe exactly hwo they work. Then we can start picking each other's minds about what changing anything will do.

I would do it but I am one of those who are among the clueless. :)

J. J.
 
#25 ·
Well said.

That was the intent of this thread. (And for that fact most threads on the board)
To have those who know share their knowledge with others.

I would be the first to admit that I am deficient in the world of hydraulics.

I however understand the math behind it.
That said, I was hoping to benefit from others “real world” experiences.
People who work with power steering pumps day in and day out.

So i guess that takes us back to square one.

To know if the modification is successful we need to know what the starting point is.
Again: I would like to see flow vs RPM and/or pressure vs RPM charts.
Are the graphs linear? Or does Flow/Pressure fall off at lower RPM’s?

If I can buy a stock pump and it works with out mods then why bother?
But "IF" the mods gain me some advantage, then sure lets do it.

I almost think it would be worth while to put a flow meter on my system and do some before and after testing...


In the following link he uses a stock Cadillac power steering pump. Why?
Is there something special about that pump or did he just run the numbers backwards to find parts that would work with it?

From the Tech section:

This step is probably the most likely entry point for those reverse-engineering a system, as the limiting factor is likely to be the pump used. That is to say, it's not as if there are suitable pumps available with an infinite range of flow rates. It should not be too hard to take the flow rate of your pump, and reverse the equations to calculate what sort of steering speed, number of turns lock to lock, size of cylinder to use, and steering force are supportable. The other option is to use the excel spreadsheet below and keep tweaking all the variables until satisfied.


http://www.akfabshop.com/alaskaoffroad/hydro_steering.htm
 
#26 ·
ya.. i have read a lot on the internet.. and i take what i can from it.. if it doesnt fill my bowl all the way.. then i just take what i believe to be true and run with it on my own.. my info will be slow as i am moving right now.. but i plan on enlarging the box for more fluid holding capacity.. and a larger return line with a larger opening in the box.. and i drilled out the outlet fitting for more flow.. hoping to get a little quicker steering.. i might try raising the pressure up some too..
 
#27 · (Edited)
Graph I found:
(Still looking for a P pump one)




From the chart supplied in the PBB tech section the TC pump can supply 2.4 -2.8 GPM.
However at 900 RPM's only 1.8 GPM. When you need it the most!

For "my system" calculations, I will require 2.5 GPM minimum (at Idle).

So is there any proof that the flow modification works at low RPM's.
-
-
-
 
#28 ·
just by feel it seems my tc pump mod did not increase flow at idle. but i just drilled out the main fitting. some where i read something about a mod that will deliver more flow at idle but I can't for the life of me find that info. If memory serves me right it involved drilling the orfice on the side of the main fitting. Maybe ill give it a try and see what happens. just out of curiosity why do you feel the need for more flow at idle? I can see the need for more pressure when idling in the rocks as it takes more force to turn the tires when there not moving. More flow for when your going fast as you need to turn quicker when your haulin. at least thats what ive notice as my steering seem too slow when im going fast but works fine in the slow stuff. but i don't compete either.:(
 
#29 ·
To start, I am no steering expert. What I know and have learned has been dealing with the hydroboost set ups I make.

Do you need to modify your pump?

The simple answer is who knows? Put the shit together and see if everything works. If it does then no, if it doesn't then maybe.

The hard part about this is getting a pump that's actually the pump you ordered. I can't tell you how many times someone has bought a Chevy Truck P Pump and it didn't solve any problems yet it should have. I send them the same pump and bam, problem solved.

This is because of a lot of fucking shady ass power steering rebuilders, none of whom work the off road market. We're talking chain stores here, Napa, Auto Zone etc. A truck pump and a car pump internals are interchangeable. Car parts are cheaper, so rebuilders have taken to putting the car parts (cam etc) into the truck body and calling it good. This actually will work ok on most non modified vehicles, but won't do shit on modified vehicles (anyone running unmodified vehicles here? Nah didn't think so).

So the first thing you need to do is make damn sure the pump you bought is actually built correctly. I have never gotten a pump from Howe, PSC, or AGR that was not built correctly. I have almost never gotten a pump from a dealer that was not correct, make damn sure they're not rebuilt, dealers like to cheat. I actually get my P pumps from Durex, they're another family business like mine and build my pumps to the exact specs I ask (so do the other companies I mentioned, Durex is local to me).

Best advice when buying a pump from an Auto Parts store. Ask them who builds their pumps, I'd shy away from anything A-1 Cardone and anything from Canada. I am speaking for modified vehicles here, locals build them the best, but still chancy.

I've seem P Pumps that put out between 1,250-1,500 PSI and 2.8-3.5 GPM. I don't know what vehicle or type has the higher or lower ends. I order everything at 1,500 3.5 and never needed to know. Can't help you there. But ever at lower levels that's enough Pressure and flow to work most single upgrades.

OK, get a good pump, now do I need to upgrade it?

If you actually have in your possession a true Chevy truck P pump and...

You're just adding a hydroboost, then no you won't need to upgrade it. It'll work just fine 95% of the time.

You're just adding full hydraulic steering (note: I am not a steering expert) from my experiance maybe. It depends on the size of the rams, how many rams etc. Lots of guys don't upgrade and are fine, I know that doesn't help you a lot...

You're just adding ram assist steering. A good maybe here, it's actually harder to get ram assists working then full hydraulic.

You're adding hydroboost and ram assist/full hydraulic. Yes, you should upgrade your pump to 1,500 PSI and 3.5 GPM. It may work fine without an upgrade on the street, you will notice a huge difference in the rocks etc.

Is there such a thing as too much flow and pressure?

I have no clue what so ever when it comes to just steering.

With a hydroboost yes it matters. That pressure and flow needs to get through the hydroboost. If it doesn't it can back up on you, shear a shaft, get hot, do many bad things to the pump. 1,500 and 3.5 can easily be handled by a hydroboost. If you add ram assist it may or may not work. Using your brakes may cut off enough pressure and flow to do anything from actually stopping all your steering, to having a lesser amount of steering. You won't know until it's all together. A simple test of turning your wheel and stepping on the brake pedal will tell you if it won't work.

If it doesn't work you can try and use a pump with lesser pressure and/or flow but I don't know what will happen. Seeing as we hi flow the hydroboosts so it won't happen we never tried that out much. You know, if it aint broke why fix it type thing?
 
#30 ·
With a hydroboost yes it matters. That pressure and flow needs to get through the hydroboost. If it doesn't it can back up on you, shear a shaft, get hot, do many bad things to the pump. 1,500 and 3.5 can easily be handled by a hydroboost. If you add ram assist it may or may not work. Using your brakes may cut off enough pressure and flow to do anything from actually stopping all your steering, to having a lesser amount of steering. You won't know until it's all together. A simple test of turning your wheel and stepping on the brake pedal will tell you if it won't work.

If it doesn't work you can try and use a pump with lesser pressure and/or flow but I don't know what will happen. Seeing as we hi flow the hydroboosts so it won't happen we never tried that out much. You know, if it aint broke why fix it type thing?
Van,

Good info. Thanks.

What can you tell us about modifying our hydroboosts for better flow?
 
#33 · (Edited)
Just as a quick reference,
What is the stock drive ratio on P-style pumps?

My bracket and pulley techs are reccomending a 1:1 ratio, but I seem to remember 85% being the norm...

AND, if anyone with guru knowledge would care to answer:
1. What will underdriving do the the fluid? Obviously it would cure most people's idle flow/psi problems... but are there drawbacks? If so, do they occur at a certain pump shaft speed (rpm)?

2. Where is the fluid hottest, and thus in need of cooling? Can a power steering cooler be better or worse in a certain link in the pump-hydroboost-hydrosteer chain?

3. Lastly, does anyone know any dudes from PSC? Seems to me that a little update to this page http://hydraulicsteeringtech.com/ might serve this threads visitors well

Subscribed
 
#34 · (Edited)
Just as a quick reference,
What is the stock drive ratio on P-style pumps?

My bracket and pulley techs are reccomending a 1:1 ratio, but I seem to remember 85% being the norm...

AND, if anyone with guru knowledge would care to answer:
What will underdriving do the the fluid? Obviously it would cure most people's idle flow/psi problems...

Subscribed
From what I've heard either nothing or everything. For some people it solves their problems. For others it spins the fluid into a frothy useless mess. I know my current pump froths everything up good at any rpm over 3000. If I udnerdrived it it would just happen sooner.

J. J.
 
#36 ·
I am running rear disks, hydro boost, stock store P pump, 1.75" PSC assist ram, My steering works fine, hydroboost is also unmodded but I am going to get Vanco to hi flow it when I go full hydro. I thought i would have problems with the HB and hydro assit, but you dont know till you try, you might get lucky.
 
#37 ·
I also have one of those school bus pumps. I have not installed it (yet) I do know PSC uses a delphi(?) pump that is wider in the pump rotor area (more GPM) and this helps alot in a rig.
I think the bus pump is just about what us rockcrawlers want, think how hard it is to turn those 10.00 x 20 bus tires sitting still on pavement with a 120# woman behind the wheel... (your bus drivers size may vary)
Additionally, the bus pump has a keyed shaft and nut/thread setup eliminating the puller problems when changing a pulley...
it IS uglier than a dogs ass. but will it work??
cheap at salvage yards, expensive at NAPA
who is runnin' one??
 
#39 ·
I think the most important thing to remember is a power steering system is hydraulic, which means there is no rocket science involved.

1- you must have a cooler; heat kills!
2- increasing RPM's of the pump, increases flow which also increases heat
3- increasing pressure of the pump also increases heat
4- you need flow to create pressure; at some point flow and pressure will max out and cavitation will start
5- pump must have a constant supply of oil to pump and it must be air free and enough to keep supply and demand constant or cavitation will start

Cavitation is where the pump is pumping, but no fluid is moving.


From there you can start modifying things...

Making the pressure relief spring stronger increases pressure - keep in mind, if the pump can't supply more pressure, then it won't.

Increasing the hole size increases flow at all times. Again, if the pump can't deliver the increased flow, then it won't.

Overdriving the pump will increase flow/pressure at lower RPM's, but at higher RPM's bring on a whole nother set of issues that will need to be addressed... Heat, etc.

...You all already knew all this, but keep it simple and remember the basics.
 
#46 ·
IIRC, one of the PS techs I talked to told me he only saw remote res #143's on his parts schedule, but I always see them with a res on top in any catalogs... would require a call back to Texas Power Steering, which is probably in order, as my hydroboost bracket is being made now...

Sorry I forgot to include the prices. I need to go back to the 'cut' and 'paste' section of my laptop tutorial handbook.
 
#43 ·
One question thats just popped into my mind, i will be upgrading to full hydro over the winter, and it will be to a system to get it to turn as quik as i possible can with as few turns lock to lock as possible, now i am wondering, with these pumps that use a remote resivoir, what would happen if 2 pumps were used and the first pump's pressure line fed into the second pump's low pressure/intake line?? Would if be possible to multiply pressure while keeping the flow the same, or would it be best to just merge the 2 pressure outlets together?
 
#44 ·
I would say "no" for the series pumps. The inlet of the second pump is not designed for "high" pressure.

Now if you search around I have seen posts that talk about running two PS pumps in parallel to gain more flow. I would equate it to trying to run two engines to gain more torque. I think you are better off running one pump that meets your needs
 
#45 ·
Yeah i'll probably be just running one pump, but it was an idea (lot of different types of pumps out there) and was curious about it.


Anyone know what style of pump is found on some of the f700 and heavier ford indrustial trucks, as those pumps are pushing a factory ram assist setup (in some trucks anyway, we have 2 of them on the farm and both are the same setup), and they have the resivior/pump/cooler all on the same bracket.
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top