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Power Steering Question

dbrannon79

dbrannon79

I'm getting there!
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Seguin, TX
Hey guys, as I have talked about in the past with working on and changing out parts on my rig for the power steering and hydro-boost system, I figured I would start a new thread here since I have noticed these new happenings.

My steering wheel and pedal feel has always been a little on the stiffer than I would like to see side. I have recently noticed with these cooler mornings lately that when I start my truck up and take off, the steering wheel and pedal almost feels like butter for about the first 7-10 minutes of running, then returns back to the stiffer feel like it always has been. There is no noise coming from the steering or braking system.

is this something trying to tell me the pump or other part is needing some attention?

recapping on what all has been done to the system. the pump has been re-sealed by myself, rebuilt the Cardone gear box myself after finding it was sloppy from the get go, and the hydro-boost had been replaced right after I got the truck due to it leaking. the system has been flushed before. most recently flushed after rebuilding the gear box.

one thing I do know is even with the factory cooler on it, the metal lines do get quite hot when running, no so hot you can't touch them but hot enough it's uncomfortable to leave your hand on them very long. I have never tried to get a temp reading on how hot the fluid gets but I do know that on a longer driving run, it gets fairly hot.

to describe the recent feel of the steering in a cool morning is almost like steering a small passenger car, but that is a brief amount of time until things start to warm up. Once warm, it's not like it doesn't have any power steering, I can still steer it with one hand but it takes a little more effort. The brake pedal feel once warm is in a sense comparing to my wife's or daughters car, if I were to step on the pedal in there car like I do my truck, I would send everyone through the windshield! it just takes more effort in my truck. the more effort needed thing has been going on ever since I owned this truck and I really don't have access to another similar rig to compare to.
 
@dbrannon79 you're describing the exact same symptoms my truck has except mine causes brake drag when the steering is tight. Metal lines off the hydro boost to get extremely hot. Sometimes it feels like the power steering pump isn't really doing its job very good but working. Other times it's almost like fighting the wheel a small bit. Just out of curiosity did you do a brake bleed or anything that involved opening a brake line about the same time? Change the caliper or something like that.?
 
head scratcher for sure.

First - what fluid are you using? I would be running a pure synthetic atf.
But I would take temp readings first before putting in new fluid.
Pull a sample of the fluid into small glass container and put some new fluid of whatever you put in there to compare. Let the fluid settle a day on a shelf with no movement so anything that needs to (ie water) can separate and drop out.

Are you running a filter in the system?

Then get a pressure test kit. I don’t remember procedure but we can dig one up. My hummer manual is tucked away but has it. For those that don’t know- find military manual for your rig when possible- yes they have one for the gmt400 - because theirs covers all this oddball stuff usually. Obviously temp testing at that time also.

You have to eliminate that something is wrong with fluid first, then pump.
Cant test pump with bad fluid, cant test other parts with wrong temp fluid, pressure, or flow.

Next, you need a drive location where you can do this: bypass the power steering box so only the brakes are getting the boost. Drive and analyze. Now swap so no power brakes only power steering, drive and analyze. You should be able to tell where the issue is.
Yes it is possible both box and brake booster are goofed.
But this is the only way I can see to do this.
 
the fluid was from O'rileys auto, bought their house brand gallon jug. it was clear when it was put in but now shining a flashlight in the fill hole you can see it's kinda darker.

where can I get a pressure test kit relatively inexpensive or rent? will a temp probe like the digital ones used for baking and cooking meat in the oven work if I place it on the steel line and wrap it in some insulation to watch how fast and hot it gets?
 
Btw, people argue about using ATF vs the clear power steering fluid.
The saginaw pump went into gm trucks in 1963, with atf.
It wasn’t until Honda in the mid 70’s released the first dedicated power steering fluid.
GM continued using its atf until the 1990s when they realized they could make more profit and released a power steering fluid for the saginaw. Then, much like the dexcool debacle, they relased power steering fluid version 2. Then 3. Then 4 and figured out one finally that worked almost as good as the atf.
All gm and ford vehicles sold to the military as go-to-war units were sent with atf not ps fluid. Hmmm.

You will hear about friction modifiers in atf and maybe they hurt the ps pump. That is because these people never disassembled a saginaw pump and compared the vanes to the clutch material used in transmissions. If they had and realize it is the same material... they might quit freaking out.

In fleets we ran gmt400 trucks with atf in the ps pump, never flushed, only replaced it when a repair was needed, which would usually be hose leaking. 250,000-300,000 miles on atf was normal.

Take a little atf and a little ps fluid, heat them on the stove top to 325f and tell me what you think is better
 
@Will L. . I was planning on doing what you said earlier. Bypassing the power steering pump and then bypassing the hydro boost. And this will probably help @dbrannon79 also, the hoses from the power steering pump to the hydroboost ETC do they all have the same ends on both ends? As in can I remove one of the hoses and connect both ends of the other hose to just the power steering pump? So basically going in and right back out? Haven't had them off in a long time so I don't remember what the ends look like to go into the pump.. and since I just got a bunch of ATF on sale Dex/Merc, can I just dump the fluid out of the system and put the ATF in or do I have to do something in between,
 
Thanks @Will L.

iirc the two line fitting on the box or the HB are different sizes. I understand the concept on bypassing the HB and only having the box in the system. how do you bypass the box? I was thinking about it and if one was to take the two lines off the connect them together, I feel like that would blow pressure into the return line wouldn't it?
 
I was thinking it would basically just complete a loop. If I understand right I think fluid flows through the hoses back and forth depending on which way you turn the wheel. So if you turn wheel one way the pump push the fluid through one side turn it the other way and then it goes the opposite way but I might be wrong.
I got 2 gallons of ATF I'm waiting to try this once someone tell us how to connect the lines.
 
bypassing the gear box takes the steering wheel out of the equation. turning it wouldn't do anything for the pump. what I would fear is blowing up the cooler or the soft rubber hoses. I think we would need to plug off the pressure port for the line coming out of the HB that goes to the gear box since the HB has it's own return line back to the pump.

@Will L. or someone will correct us soon I'm sure.
 
Will L. said:
Btw, people argue about using ATF vs the clear power steering fluid.
The saginaw pump went into gm trucks in 1963, with atf.
It wasn’t until Honda in the mid 70’s released the first dedicated power steering fluid.
GM continued using its atf until the 1990s when they realized they could make more profit and released a power steering fluid for the saginaw. Then, much like the dexcool debacle, they relased power steering fluid version 2. Then 3. Then 4 and figured out one finally that worked almost as good as the atf.
All gm and ford vehicles sold to the military as go-to-war units were sent with atf not ps fluid. Hmmm.

You will hear about friction modifiers in atf and maybe they hurt the ps pump. That is because these people never disassembled a saginaw pump and compared the vanes to the clutch material used in transmissions. If they had and realize it is the same material... they might quit freaking out.

In fleets we ran gmt400 trucks with atf in the ps pump, never flushed, only replaced it when a repair was needed, which would usually be hose leaking. 250,000-300,000 miles on atf was normal.

Take a little atf and a little ps fluid, heat them on the stove top to 325f and tell me what you think is better
Click to expand...

I love this. You wouldn’t believe the number of Toyota 4Runner guys who insist that you should use Toyota engine oil, Toyota ATF, even Toyota 75w gear oil in the transfer case. They do so because the manual spec Toyota Fluids or equivalent. Problem is no one makes a straight 75w synthetic gear oil and if you can get it from Toyota, it’s $80/quart. I regularly post the non-OEM fluids that I’m using, then let them know the truck has 313K miles on it.
 
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