Power steering Pump Volume and Pressure Upgrades

Post by **HenryJ** » Fri Jan 27, 2006 8:24 pm

Powersteering Pump Volume and Pressure Upgrades
Something to consider for those running bigger tires. There are times that my pump does not have enough at idle pressure. I may just try this.

killian96ss · Post by **killian96ss** » Fri Jan 27, 2006 10:16 pm

HJ, I understand what you are trying to do, and I would recommend talking to one AGR's techs to discuss getting more idle pressure from your PS pump. The mods listed in the article you posted do not sound safe, and the PS pump should be pressure regulated to work with the valving in the gear box. The last thing you want is to have your PS pump blow some seals and lose almost all your PS assist which can easily cause an accident.

I highly recommend AGR. I am personally using one of their high flow PS pumps and racing valved gear boxes in my SS. I am very happy with the quality and performance of their products. I know for sure they can make a high pressure pump for Chevy 4x4 applications. Another great PS pump company is Turn One Inc. Thes guys build most of the pumps for Nascar and the 2 owners used to be the lead engineers for Saginaw, GM's steering division. I know they can also custom blueprint PS pumps for any application.

Steve

GeorgesBlazah · Post by **GeorgesBlazah** » Sat Jan 28, 2006 5:45 am

ohhh this i may hafto look into...my ps pump stinks turning the swampers around.

Post by **HenryJ** » Sat Jan 28, 2006 6:55 am

killian96ss wrote:...The mods listed in the article you posted do not sound safe...

As with any mod , there is no doubt that you could really mess things up.

What it is doing is changing the volume available and increasing the pressure by adjusting the pressure relief. The article does stress "baby steps".

Sure modifications to steering components should be done with caution. This whole website / forum has the disclaimer that you offer "mod at your own risk". Done properly I see no safety issues. Adjusting a pressure relief valve is really not a big deal. I just wish I had thought of it

That may be all AGR is doing to their "P-pumps"?

AGR wrote:The P-series pump is designed to provide increased flow and pressure for 2WD light trucks and SUV's. The increased flow provides for better response in quick steering situations.

It is not like their pump is a different design perse.

I would suggest a very little at a time. You will have taken too much when you lose the feel of the road and it is "super steering". The late sixties Caprice, Impala, and early seventies Monte Carlo had this issue. The pressure and volume were high enough you could steer with your little finger, but really did not get the feedback from the road that makes me feel comfortable.

I'll probably grab a valve from a bad pump at the salvage yard to play with.

killian96ss · Post by **killian96ss** » Sat Jan 28, 2006 8:25 am

The easiest way to achieve more idle pressure would be to swap in a slightly smaller PS pump pulley. You can easily blow the seals in the gear box with too much pressure, and like I mentioned above the PS pump needs to be pressure regulated to work with the valving in the gear box to work correctly. Be very careful if you decide to try that PS pump pressure mod. The guy who wrote the procedure sounds a little unsure of his own write up. He says things like "these mods are designed for OFFROAD USE ONLY!!!", "I've actually built so much pressure that I blew a section of the top of the steering box about 40 feet across the shop. OOPS!"

, and "I have no hard evidence that this works".

I would like to say just one more time BE CAREFUL.

Steve

Post by **HenryJ** » Sat Jan 28, 2006 8:29 am

killian96ss · Post by **killian96ss** » Sat Jan 28, 2006 8:34 am

HenryJ wrote: K

Oh well at least I tried to talk you out of this one.

You really are as stubborn as me!

Steve

Post by **HenryJ** » Sat Jan 28, 2006 8:41 am

Sorry not a chance in heck. I have played with pressure reliefs on pumps before, although I don't know why I haven't done it with steering pumps?
It would be nice to have it selectable or adjustable like an adjustable brake proportion valve , EGR restrictor or fuel pressure regulator.
It is one of those things that once the adjustment is made you will never need to change it again. Modifying one to work makes more sense.

killian96ss · Post by **killian96ss** » Sat Jan 28, 2006 9:07 pm

HenryJ wrote:It would be nice to have it selectable or adjustable like an adjustable brake proportion valve , EGR restrictor or fuel pressure regulator.

Now that would be cool.

I would buy one if someone made one.

I could use one to lower pressure on my SS which would help prevent boil over when doing auto-X or road races. I have an adjustable brake proportioning valve just sitting in the garage, but like most of them, this one has very small inlets and outlets which would probably restrict too much flow, but they are definitely rated for high pressure which is good. I wonder if I could drill out the openings to fit larger fittings? I really like the lever type proportioning valves since you can adjust them very easily and they have like 4 preset positions that could be used to reduce pressure as necessary.

Steve

Post by **HenryJ** » Wed Jul 19, 2006 10:33 am

Came across another article- Valve mod page

Power Steering box valve mods for the XH and other quick ratio, high effort boxes

When installing the XH steering box in place of a stock G box, the power steering pump pressure valve (flow valve-alternate name) needs to be changed to one that was used on a Camaro with that box. The higher effort and faster ratio needs a little boost in maximum pressure, and flow, to help it turn smoothly and quickly under all conditions.

The mod involves changing the spring, pressure fitting (with orifice), and removing all washers (if present) from the flow valve. The spring will actually lower the minimum pressure slightly, which helps reduce assist when driving straight ahead. Removing the washers from the flow valve increases the maximum pressure the pump produces, and is needed when turning the steering wheel rapidly left and right. The fitting also produces slightly more flow than stock, which also helps the pump 'keep up' with the demands from the box.

The following text is by Bob Morris, who originally figured this conundrum out

"The new spring is shorter than either the original G spring or the F
spring I pull out of the 91 F car. To do this swap I'd only buy the spring
#5688037 @ $4.68 (list), the fitting #26009894 (o-ring included with new
fitting) @ $15.03 (list) and use the old valve. Insert a 1/8'' drill bit into
one of the holes in the side of the valve and hold onto the valve with
channel locks using the bit to keep the valve from turning in the pliers, do
not scratch the machined surfaces of the valve. Wash the valve out and make
sure the screen in the valve is clean, do not reinstall any washers and
Locktite the nut back on the end. The new valve # 7809232, $22.69 (list) is
the same body and internal pieces and orifice sizes for all three valves,
only the shims vary, use the original valve, without the shims.

Drilling out the orifice in the fitting would be tricky as there is a very
small hole drilled in the side of the fitting into this orifice and it may
burr, clogging the hole. A #27 number drill is .144'' and could be used to
drill the G fitting out. But at $15 for the fitting which includes a silicone
o-ring (not rubber), I'd just buy the new F fitting or get one from a donor
at the yard.

Only other parts you'll need is a new 3/8'' O-ring for the P/S high
pressure line and a quart of P/S fluid. The tool list is short, a 16mm open
end for the high pressure line, 1'' socket and a magnet to get the fitting,
valve and spring out of the pump. An 11mm box wrench, 1/8'' drill bit and
channel locks to remove the washer from the valve and Locktite to reassemble
it. This swap is easily done on the car and improved the slow speed assist
and feel considerably, no more lack of assist at low speed and the high speed
feel is about the same as before the changes, a definite improvement."

The total cost should be around $25, depending on how good a price the dealer will give you. The 1" socket is necessary to remove and replace the fitting on the back of the pump, a wrench won't fit into the small area there!

This is an easy mod and will make the XH and similiar boxes feel a lot better. The road feel actually improves, and the steering wheel can be moved as fast as you want, with no lagging.

Created 11/13/2001 by Jeff Davidson

If I come up with a ZQ8 steering box, I will try this one.

Post by **Walt** » Wed Jul 19, 2006 10:46 am

My PS pump has been acting strange as of late (the last month or so). At times it's hard to turn the wheels when I'm stopped. Sometimes it's works fine though. I've added that to my list of problems for when I take the truck back to the dealership.

EDIT: On another note, are you planning on swapping the entire box from a ZQ8? I've heard that their steering is tighter, and that the end to end turning distance on the wheel is less.

Post by **HenryJ** » Wed Jul 19, 2006 11:04 am

Walt wrote:...are you planning on swapping the entire box from a ZQ8? I've heard that their steering is tighter, and that the end to end turning distance on the wheel is less.

Yes. Faster ratio. One less turn lock to lock. Stock is 14:1 and 4 turns the ZQ8 box is 12:1 and 3 turns. This may or may not be a good thing for a truck with big tires. It will increase the effort to turn them.

My truck also tends to lack a little at idle speed when trying to turn the wheel. Only while not moving have I noticed this. This was part of why this topic interested me.

After a little more research I decided to order the parts for the pump valve mod.
Parts: 26009894 , 5688037 , 5688035 total $24.29

This last article is a bolt on. No drilling or experimentation. It matches the Camaro pump configuration. I like that idea.

Post by **Walt** » Wed Jul 19, 2006 1:24 pm

The other day, when I aired down, I could turn the wheel at all when stopped.

Post by **HenryJ** » Wed Jul 19, 2006 2:04 pm

Check your fluid level and condition. There have been pump failures.

Post by **Walt** » Wed Jul 19, 2006 2:35 pm

Fluid looks fine, and is at the right level.

Post by **HenryJ** » Wed Jul 19, 2006 2:39 pm

This mod might help you out, or finish off an already weak pump.
I have had mine stall a couple times. Bringing the rpm up just a little cures it.
I am hoping this mod will eliminate that occurrence and be a good "pre-mod" to the ZQ8 box.

daevans315 · Post by **daevans315** » Wed Jul 19, 2006 7:47 pm

Walt wrote:
EDIT: On another note, are you planning on swapping the entire box from a ZQ8? I've heard that their steering is tighter, and that the end to end turning distance on the wheel is less.

The ZQ8 steering box is noticably quicker, and I really don't notice much differance in steering effort. Running 255 45 ZR17's on my ZQ8 and its about the same steering effort as the stock 235's on the crew. I wonder if they don't play with the pump pressure to make up for the loss in mechicanical advantage.
The problem I have with the ZQ8 is that I can out crank the power steering in a slalom on the autocross course. If I'm not 2 foot driving and keep the RPM's up about 1500 or so I can turn the wheel faster than the pump can keep up... loosing power steering in the middle of 50 mph slalom is annoying. Having it come back a few seconds later is usually catastrophic.

I just spent 10 mins looking for the video of this actually happening to me. It generated a nice 360 with lots of tire smoke... I can't find it though. This is as close as you get.

My wipeout Movie

killian96ss · Post by **killian96ss** » Wed Jul 19, 2006 7:55 pm

daevans315 wrote:loosing power steering in the middle of 50 mph slalom is annoying. Having it come back a few seconds later is usually catastrophic.

I just spent 10 mins looking for the video of this actually happening to me. It generated a nice 360 with lots of tire smoke... I can't find it though. This is as close as you get.

http://www.ubergobbie.com/albums/wpw-20 ... 0-oops.mpg

Cool video!

Is that you driving the S10?

Steve

daevans315 · Post by **daevans315** » Thu Jul 20, 2006 4:58 am

killian96ss wrote: Cool video! Is that you driving the S10?

Steve

Yep, thats me, not one of my better runs but it was fun. I can't blame that spin on anythnig but a over active right foot.

Snoman002 · Post by **Snoman002** » Thu Jul 20, 2006 11:37 am

First off you don't need the fairly rare ZQ8 box, there are LOTS of boxes out there that will just bolt up and give you the quick ratio steering.

http://www.chevelles.com/techref/shea_3.html

The link is a list of the Saginaw 800 boxes that should just bolt right into the truck, there MIGHT be some issues with power steering hoses on early model boxes though.

A few things to take note of:
Check the t-bar size, this determines the effort of the steering. A thicker t-bar=less assist, thinner t-bar=more assist, or alternately a really thin t-bar will give you that "Super Steering" HJ was mentioning earlier. If you want you can take a ZQ8 box, or other high ratio boxes, and switch it to a smaller t-bar, that will give you back the assist you may loose from switching to a high ratio box.

The other thing to take note of is the internal stops. F-body boxes suck as they have high internal stops and will greatly increase the turning circle. Since the steering stops on 2nd gen S-Series trucks are on the LCA's I would get the highest amount of travel possible.

I have also heard that FLOW is more important than pressure, this was on a car though so off-road and big tires were not a consideration.

I'm seriously considering switching to a 1992-98 Grand Cherokee box as it has the greatest amount of travel and a quick ratio. Granted it has a high effort but I'm only running 31's and mostly street drive the truck. If I do this though I'm switching to 2nd gen LCA's and spindles so I have the stops on the arms so I don't blow out the CV's. This would also allow me to run the later model sway bar which is MUCH easier to disconnect than the bar I have now, plus I think some of the later model sway bars are thicker than any of the early model bars (best of both worlds).

Some more links:
http://www.chevelles.com/techref/ftecref29.html
http://www.classicperform.com/tech_arti ... n-turn.htm
http://www.chevelles.com/techref/ftecref29.html

Snoman002 · Post by **Snoman002** » Thu Jul 20, 2006 11:50 am

Also, don't forget to adjust the steering box.

It should take 20 in-ls's (if I remember correctly) of torque to turn the output shaft off of center. This needs to be done with the box off the truck. You adjust the amount of force using the lash adjustment on the top of the box. I have heard this is FAR better than tightening the lash adjustment and then backing it off half a turn, although that works for some.

killian96ss · Post by **killian96ss** » Thu Jul 20, 2006 1:07 pm

Snoman002 wrote:Also, don't forget to adjust the steering box.

It should take 20 in-ls's (if I remember correctly) of torque to turn the output shaft off of center. This needs to be done with the box off the truck. You adjust the amount of force using the lash adjustment on the top of the box. I have heard this is FAR better than tightening the lash adjustment and then backing it off half a turn, although that works for some.

I've had great success tightening the sector shaft adjustment nut until you feel a slight amount of resistance and then backing off 1/4-1/2 turn.

If you have never done this before it may take a little trial and error the first couple of tries, however I've done it so many times on various vehicles that I'm able to get it right on the first or second try.

You eventually develope a feel for the correct amount or resistance needed.

Steve

Post by **HenryJ** » Thu Jul 27, 2006 4:53 pm

Ok, the parts arrived a couple days ago. The fitting orifice measured .141 with my dial calipers. They have not been calibrated since new. They were zeroed however. There may or may not be a difference from the reported size of .144 that it was supposed to be.

Not being the patient sort...I installed this evening.

Three words.....OMG WHAT'A PITA!

Avoid this one folks. Now to temper that a little. I waited only 1/2 hour after driving home in 103º weather after a long hot day at work.
Without a body lift there is no way. A six inch long 5/8" wrench is too long. You can not use a ratchet and socket to get the fitting out. There is physically no room to get a large hand in there. Taking it apart is bad , but putting it back together is worse. I did it but it was not something that I relish ever doing again.

Now the bad news.

The springs are the same. The fittings have very little difference. I will measure tomorrow, but it looks like maybe .005 difference is all. I did not have any washers to remove, however there was locktight on the "screened bolt" threads and it was not tightened down all the way. This may or may not have been a washerless method of calibrating the pressure relief. I cleaned off the locking compound and tightened it all the way down.
I have not driven it yet, so no impressions about whether I totally wasted my time and money.

The good news. It was time to change the power steering fluid. Mine really was in need of a change.

More after a test drive.

Post by **HenryJ** » Fri Jul 28, 2006 7:12 pm

Feels about the same. The stock fitting measured .137 , so very little difference from the .141 fitting that was ordered.
No stalling, but I have yet to really test it.

Post by **HenryJ** » Sat Jul 29, 2006 8:44 am

Burns and blisters healing, I now have a little time to reflect clearly.

Unless the guys running the wider 33's find a need for more power from the powersteering, this is probably not something that needs to be done.

I am still anticipating making the switch to a ZQ8 steering box, so I may still have a need for this modification.
I do still have one "ace up the sleeve" I have a fitting from a used pump with an orifice diameter of .153 I also have a couple more springs to choose from. This formula would be difficult to duplicate as I have no applications with which to research part numbers. Suffice it to say that there are quite a few differences in the available valving out there.
Once a good combination is determined , then modifying your existing parts and perhaps ordering a $4 spring may be the best solution.

Post by **HenryJ** » Fri Aug 18, 2006 6:02 pm

I have not had the steering stall at all since this modification. Maybe it did do the job?

Post by **HenryJ** » Fri Dec 08, 2006 1:01 pm

I think the modification was worthwhile. I have had no problems turning under any conditions. I think the pump, box , tires, stabilizer, are all working together as they should.

killian96ss · Post by **killian96ss** » Fri Dec 08, 2006 2:37 pm

It sounds like you may have had some problems with your stock power steering system if the upgrades made things better.

I have never had any problems with my stock power steering system and 31" tires.

Upgrading to a 33x9.5/15 tire will not create any more turning resistance since the contact patch would be about the same as a 31x10.5/15 tire, maybe even less

Steve

Post by **HenryJ** » Fri Dec 08, 2006 2:48 pm

killian96ss wrote:...Upgrading to a 33x9.5/15 tire will not create any more turning resistance since the contact patch would be about the same as a 31x10.5/15 tire...

Oh, but it does. The difference was very noticeable after changing to the larger diameter tires.
There was nothing wrong with my power steering system, unless the pressure relief not being completely tightened flush was unintentional. The minor upgrades in flow and pressure were just enough to match the set-up.

There is a reason that there are so many different pressure relief valves and that when you change pumps you must use the pressure relief that came with your vehicle. They are matched to the application.

IF you have any hesitation in the power steering at idle speeds this is a good fix. If you don't , there is no need.

F9K9 · Post by **F9K9** » Fri Dec 08, 2006 3:20 pm

HenryJ wrote:..........IF you have any hesitation in the power steering at idle speeds this is a good fix. If you don't , there is no need.

I know I had trouble on the minor solid rock stuff I did a couple of weeks ago when my spotter told to me to turn more driver or passenger. It felt like my steering column was locked. It might be a needed mod for me but, not one I would undertake to do myself

Post by **HenryJ** » Fri Dec 08, 2006 3:25 pm

f9k9 wrote:... It might be a needed mod for me but, not one I would undertake to do myself .

Agreed I think that gathering the parts and building a replacement pressure relief valve would be no problem, but the swap could end up a nightmare

If it happens regularly, or if time comes that your pump needs to be replaced, then would be the time to make a change.
In the mean time change the fluid and keep an eye on its condition. You are going to be working it harder than most

We have both added several things that make the steering work harder. Larger tires, steering stabilizer, quick ratio steering box, reduction in wheel rearspacing, additional weight. All the little stuff adds up.

killian96ss · Post by **killian96ss** » Fri Dec 08, 2006 3:27 pm

HenryJ wrote:IF you have any hesitation in the power steering at idle speeds this is a good fix. If you don't , there is no need.

I agree with you here, but I still don't see how 2 tires with the same contact patch will create different loads on the PS system.

The contact patch creates most of the resistance, so if you upgraded to a larger 33x10, 33x12, or larger tire with a bigger contact patch, then I could see how this mod would improve things a bit.

Steve

Post by **HenryJ** » Fri Dec 08, 2006 3:38 pm

killian96ss wrote:... I still don't see how 2 tires with the same contact patch will create different loads on the PS system.

They do not have the same contact patch or characteristics- Tire Selection for Expedition Travel- A white paper
The narrower tire actually provides more downforce and since the contact patch is vertical rather than horizontal better friction (traction).
I see your point in a reduced diameter and wider tire, but the difference in the larger diameter and increased deformation in a narrower tire must have been the difference. I would not have bet there was much a difference, but found out different with first hand experience.

I guess you will have to trust me that there is a noticeable difference. I am not making it up

F9K9 · Post by **F9K9** » Fri Dec 08, 2006 3:41 pm

HenryJ wrote:................We have both added several things that make the steering work harder. Larger tires, steering stabilizer, reduction in wheel rearspacing, additional weight. All the little stuff adds up.

Good to know what to look forward to. That area we were in is pretty close to being highly restricted. I know of no other areas like that within 100 miles or so. All of those shots were actually on a county road but, many have abused the nearby private land and the end of enjoying that "road" is drawing to a close. Will have to look hard at this mod if, my sources prove wrong.

County Road

killian96ss · Post by **killian96ss** » Fri Dec 08, 2006 3:44 pm

HenryJ wrote:I guess you will have to trust me that there is a noticeable difference. I am not making it up

Never said I didn't believe you

, and I'll bet you already know that I'm just being difficult anyway.

Steve

Post by **HenryJ** » Fri Dec 08, 2006 3:56 pm

f9k9 wrote:...Will have to look hard at this mod if, my sources prove wrong.

The easiest way to change the pressure relief would be what we need to figure out.

I was able to mash my hands in there and get the darn thing back in. With a cold vehicle I am sure things would have been easier. I would be tempted to try it again.
What about removal of the left side tire, exhaust manifold and steering shaft?

The tire being removed may have helped. The steering shaft had to be moved for sure. The exhaust manifold would have made some room, but I am not sure the efforts to remove it would have been worth the cost.

Pull the pump? Maybe the best way. It would require a tool to remove the power steering pulley. Setting the AC pump aside and all its connections and then pulling the mounting bracket. Sure sounds like lots of work.

I am betting I would give it a shot through the fender well without out removing so many parts. It has been long enough now that I am sure I am not fully remembering the frustration of not being able to get the new valve threads started. Taking it apart was easy. Compressing that spring and trying to start a thread in a very difficult space can be very trying.

killian96ss wrote:...I'll bet you already know that I'm just being difficult anyway.

I like to think of it as shining light in the shadows. An open mind finding all the sides.

This reminds me of the three blind men describing an elephant: "It is a snake!" ( feeling the trunk) , "It is a tree!" (feeling a leg), "It is a rope!" (feeling the tail)

Together we examine the whole animal and come to conclusions. Some times stepping back we can see the whole picture when all the sides are examined.
Hopefully we agree on the same animal, even if it is from different perspectives

Post by **HenryJ** » Fri Apr 20, 2007 1:51 pm

Just a bump and an update.

It has been long enough that I am over the pains , frustration and Have healed up after this mod.

This one did work out very well. I have had no resistance or hesitation when turning at idle speeds since I made this modification. Even in rough terrain I have had no need to bump the idle to turn.
I tried to make things worse by switching to the ZQ8 quick ratio steering box. It still works great.

I think it is a better match for the system and larger tires. It is not super easy steering. It feels natural and there is still feedback.
I would do it again

I would probably cuss, and complain, swearing never to try it again though.

What parts do I need?
GM PART # 26009894 $12.44 FITTING
GM PART # 5688035 $2.72 SEAL V
GM PART # 5688037 $3.52 SPRING V

The spring may be the same and you could drill out your fitting. That would have the mod cost under $3. For the $20 I would probably buy the parts again.

Post by **HenryJ** » Fri May 25, 2007 5:35 pm

Just a thought worth mentioning. The pressure relief on the 1999 Tahoe is variable. The pressure relief on the pump has a coil and two wires exiting. There is the ultimate solution. Variable pressure at the flip of a switch or turn of a knob. Now just figure out what we need to do to add it

rlrnr53 · Post by **rlrnr53** » Sat May 26, 2007 6:02 am

HJ, is there any end in sight to your unending mods?

Post by **HenryJ** » Sat May 26, 2007 6:06 am

rlrnr53 wrote:HJ, is there any end in sight to your unending mods?

Sometimes I wish I could stop

I just keep my eyes open for nice improvements. I don't think I will take on the variable pressure pump mod. That is unless I stumble across an easy way to do it

F9K9 · Post by **F9K9** » Sat May 26, 2007 9:16 am

HenryJ wrote:Just a thought worth mentioning. The pressure relief on the 1999 Tahoe is variable..........

If you want a heart stopper just wheel the Tahoe in the emergency mode and have the sensor, or whatever it is, go out and you lose the "resistance" feeling in a curve. Don't ask me how I know

okie s10 · Post by **okie s10** » Tue Mar 25, 2008 8:26 pm

Been readin up on this mod a bit and wondered if its' a mod that many have done? I'm sure thinking about coming up with the steering box and doin it. Reading all the posts here and ZR2 seems like an easy swap with a noticeable difference. Any pitfalls been found since all these aged posts were done?

F9K9 · Post by **F9K9** » Tue Mar 25, 2008 8:51 pm

I believe he hinted towards one that was not for the weak of heart.

Post by **HenryJ** » Tue Mar 25, 2008 9:18 pm

I have had zero problems. I know it was a real pain, literally, but it is worthwhile. As far as I know , I am the only one to have done it.