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No power steering w/brakes applied

 
  #1  
Old 04-14-2019, 11:20 PM
Obs7.3Powerstroker
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No power steering w/brakes applied

My 2000 7.3 loses all power steering when the brakes are applied. When you don't hit the brakes, it has perfect ps. What could be my problem? I have run in circles before with the same problem on my dad's excursion and never could figure it out. Tried new ps pump, ps lines, hydroboost, etc. nothing changed it. I'm hoping to not go through all that trouble again. Thanks for any advice
 
  #2  
Old 04-15-2019, 02:58 AM
derek0525
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You can try flushing it mine used to the same thing but ended up buying a new pump from Autozone and problem solved yeah some say autozone stuff is crap but its got ablifetime warranty and its going on 5 years with no problems. I did put Archoil in it before replacing it and it helped for a while but didnt solve the issue it came back.
 
  #3  
Old 04-15-2019, 04:33 AM
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Originally Posted by Obs7.3Powerstroker View Post
My 2000 7.3 loses all power steering when the brakes are applied. When you don't hit the brakes, it has perfect ps. What could be my problem? I have run in circles before with the same problem on my dad's excursion and never could figure it out. Tried new ps pump, ps lines, hydroboost, etc. nothing changed it. I'm hoping to not go through all that trouble again. Thanks for any advice
Where are you going when the brakes are applied?

If the brakes are applied, then the vehicle isn't moving. Hopefully. Right?

You mentioned "when you don't hit the brakes, it has perfect ps". Do you have good brakes? Do your brakes stop the vehicle?

If so, when you hit the brakes, and your vehicle is stopped, why are you trying to steer a vehicle that isn't going anywhere?

That's like taking a number two pencil, turning it upside down in your fist, walking out in the middle of the street, getting on your knees, and while pressing downward with all of your weight on your fist...rubbing the eraser head of the pencil in small circular motions on the abrasive asphalt until the eraser wears away. It won't take long.

Why would you do that to your front tires?

I wish I still had the writing instruments of my youth. I could use a couple of chisels right now. With them, I'd carve in stone the 11th commandment on a granite tablet for every teenager and young 20 something to read...

Thou Shalt Not Stand on the Brake While Attempting To Steer. Either Braketh, or Steereth... Thou Shalt Not Do Botheth. Thy Carriage Either Goeth, or Stoppeth. If It Be Stoppeth, What Doth It Profit A Man To Steereth?

News flash. Very old and faded news at that: Cars didn't used to have power steering or power brakes, and your grandparents managed to get by just fine without these luxuries long enough to spawn your parents. It's time to learn how to drive the way we learned how to drive...the way we were actually TAUGHT how to drive by driver's ed teachers... back when we had to rub two sticks together to generate a spark.

Seriously though... we really were taught, even when parallel parking, to let our foot up off of the brake when we wanted to steer. If we wanted to change direction of the steering axis without going anywhere, we learned to still let our foot up off of the brake and crank the wheel quickly. We learned to allow enough room for the vehicle to roll while we were changing direction, and because the vehicle was rolling while were were steering, we saved our delicate wear prone bias ply tires, listed in lettered sizes, long before radials and metric sizing were available on domestic vehicles. No one tried to brake and steer at the same time. It was unheard of, because it wasn't possible, and it was quite obvious when anyone did try it... they had little to no driving experience.

I'll admit, I looked at your profile. I had guessed under 25. I was wrong... you're profile says you are under 20. So your unrealistic expectations of being able to easily crank your wheels from lock to lock while standing on the brake are somewhat understandable... lack of driving experience (compared to many of us who are old enough to no longer toss the AARP magazines, 'cause the gray haired biddy's on the cover are looking good nowadays)... and lack of growing up in world where power assist was the exception, not the rule.

Why the difficulty in steering and braking simultaneously on a diesel Excursion and Super Duty is so markedly observed is simply due to the characteristics of hydro boost. Gasoline powered Fords of this era had Vacuum Assisted Power brakes, leaving the puny Ford CII power steering pump only one job to do... generate enough hydraulic flow to assist steering, and steering alone. Since diesels don't generate enough vacuum to harness and utilize to help out the brakes, that same puny CII pump is called upon to generate enough hydraulic force to assist the steering AND the brakes... and that system is called Hydraboost. Hydraulic boost. In this shared duty, the system is rigged so that brakes will take priority over steering. If you are steering, you shouldn't be braking... unless you are racing on a drift track.

The solution is simple. Stop steering while braking. It will save your tires. It will save your sanity. It will save your money. It will save your knuckles from tearing into your truck like you tore into your Dad's Excursion. Only to find that despite throwing every possible new part at it, the same behavior remained unchanged. If you do the same thing again, expecting different results... some might consider that insanity. Save your sanity. That's just how these trucks and SUVs are.
 
  #4  
Old 04-15-2019, 04:58 AM
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On a truck I own (another brand) the issue was the fluid. Power steering pump and brake booster shared the same fluid. I drained out as much as I could and refilled with Dextron VI and everything worked much better. I did it a second time a couple weeks later and now it works perfectly.
 
  #5  
Old 04-15-2019, 10:52 AM
derek0525
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Either way if im stopped with brakes applied or slowing down to turn applying brakes i can turn my steering wheel with my finger.
 
  #6  
Old 04-15-2019, 02:53 PM
Obs7.3Powerstroker
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Originally Posted by Y2KW57 View Post
Where are you going when the brakes are applied?

If the brakes are applied, then the vehicle isn't moving. Hopefully. Right?

You mentioned "when you don't hit the brakes, it has perfect ps". Do you have good brakes? Do your brakes stop the vehicle?

If so, when you hit the brakes, and your vehicle is stopped, why are you trying to steer a vehicle that isn't going anywhere?

That's like taking a number two pencil, turning it upside down in your fist, walking out in the middle of the street, getting on your knees, and while pressing downward with all of your weight on your fist...rubbing the eraser head of the pencil in small circular motions on the abrasive asphalt until the eraser wears away. It won't take long.

Why would you do that to your front tires?

I wish I still had the writing instruments of my youth. I could use a couple of chisels right now. With them, I'd carve in stone the 11th commandment on a granite tablet for every teenager and young 20 something to read...

Thou Shalt Not Stand on the Brake While Attempting To Steer. Either Braketh, or Steereth... Thou Shalt Not Do Botheth. Thy Carriage Either Goeth, or Stoppeth. If It Be Stoppeth, What Doth It Profit A Man To Steereth?

News flash. Very old and faded news at that: Cars didn't used to have power steering or power brakes, and your grandparents managed to get by just fine without these luxuries long enough to spawn your parents. It's time to learn how to drive the way we learned how to drive...the way we were actually TAUGHT how to drive by driver's ed teachers... back when we had to rub two sticks together to generate a spark.

Seriously though... we really were taught, even when parallel parking, to let our foot up off of the brake when we wanted to steer. If we wanted to change direction of the steering axis without going anywhere, we learned to still let our foot up off of the brake and crank the wheel quickly. We learned to allow enough room for the vehicle to roll while we were changing direction, and because the vehicle was rolling while were were steering, we saved our delicate wear prone bias ply tires, listed in lettered sizes, long before radials and metric sizing were available on domestic vehicles. No one tried to brake and steer at the same time. It was unheard of, because it wasn't possible, and it was quite obvious when anyone did try it... they had little to no driving experience.

I'll admit, I looked at your profile. I had guessed under 25. I was wrong... you're profile says you are under 20. So your unrealistic expectations of being able to easily crank your wheels from lock to lock while standing on the brake are somewhat understandable... lack of driving experience (compared to many of us who are old enough to no longer toss the AARP magazines, 'cause the gray haired biddy's on the cover are looking good nowadays)... and lack of growing up in world where power assist was the exception, not the rule.

Why the difficulty in steering and braking simultaneously on a diesel Excursion and Super Duty is so markedly observed is simply due to the characteristics of hydro boost. Gasoline powered Fords of this era had Vacuum Assisted Power brakes, leaving the puny Ford CII power steering pump only one job to do... generate enough hydraulic flow to assist steering, and steering alone. Since diesels don't generate enough vacuum to harness and utilize to help out the brakes, that same puny CII pump is called upon to generate enough hydraulic force to assist the steering AND the brakes... and that system is called Hydraboost. Hydraulic boost. In this shared duty, the system is rigged so that brakes will take priority over steering. If you are steering, you shouldn't be braking... unless you are racing on a drift track.

The solution is simple. Stop steering while braking. It will save your tires. It will save your sanity. It will save your money. It will save your knuckles from tearing into your truck like you tore into your Dad's Excursion. Only to find that despite throwing every possible new part at it, the same behavior remained unchanged. If you do the same thing again, expecting different results... some might consider that insanity. Save your sanity. That's just how these trucks and SUVs are.
Iím sorry but I donít think you read my question right. I wasnít asking how to drive or how I should use my vehicle, I was asking a perfectly legitimate question on how to fix a problem that my truck has. I donít think it has anything to with my age that I turn the wheel with the brakes applied, sometimes you just need to, and unless Iím mistaken, those trucks came from the factory with ps when the brakes are applied so Iím pretty sure that even ford realizes that you sometimes have to turn the wheel when your brakes are applied. I am 19 and I know that I donít know everything, thatís why I am on here, to ask you older guys for your advice and how to fix my truckís problems, so unless you have a tip or a piece of advice on what I can do to fix my power steering, I donít really see the need to post something that doesnít apply to the question. I noticed that other people commented that they had the same problem and they fixed it...they didnít just drive their trucks without ps so I donít think it is just my ďunrealistic expectationsĒ of my vehicle.
 
  #7  
Old 04-15-2019, 03:46 PM
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Not throwing on a zebra suit here.

This thread will be read down the road by anyone with questions or problems in steering and braking within this regard.

Y2 is superior in knowledge on these vehicles. His reply is somewhat science/advice/fact and character as well as caring with a slant toward educating future viewers.

Your request for advice is absolutely spot on and will help many down the road.

That said, a full flush is in order. Any advice should be absorbed whether taken or not, (you asked right).

My E99 is tired, but when it was fresh I still couldn't rotate at a stand still. I've had it for over 15 years and many flushes. Still can't get it to turn unless I'm rolling.

I haven't replaced the pump as it doesn't seem to be a problem. Is yours original? What are you/has been run in the system?

Before I slept with it, the original owner said he used atf. Could be my problem..............the gentleman was 84 and wore a 3 piece suit, unknown?

Let us know what you find please.

Denny
 
  #8  
Old 04-15-2019, 04:33 PM
Obs7.3Powerstroker
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I have no idea if itís the original pump, that being said the truck has 294k miles so I wouldnít be surprised if it has been replaced before. As for the fluid in it, Iíve only owned the truck for about two months and when I got it I topped it off with dex merc because it was low. The fluid already in the pump seemed to be atf fluid as well so that is a good thing. I had thought one problem could be that it got too low on fluid and got air into the system.
 
  #9  
Old 04-15-2019, 06:01 PM
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Full flush bro. Cheapest venue. Youtube
 
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Old 04-15-2019, 06:09 PM
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Front wheels travel in an arc about the ball joint axis.

Front wheels must actually rotate fore and aft while traveling through said arc.

The brakes prevent tire rotation.
 
  #11  
Old 04-15-2019, 06:28 PM
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Originally Posted by DieselDenny View Post
Full flush bro. Cheapest venue. Youtube
Definitely will do that first
 
  #12  
Old 04-15-2019, 08:03 PM
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Best flush was on Youtube, can't seem to pull it, but goog it. Outsanding tutorial!
 
  #13  
Old 04-15-2019, 08:59 PM
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Found this flush procedure under Alan Miller's Common Mods and Maintenance Links on Springerpop's website. I'm pretty sure this is the one I followed when I had my truck. I bet you'll see an improvement. I was trying to quiet the pump noise as well when I did this procedure, and it worked.

Ford Super Duty Power Steering Flush - Superdutypsd.com
 
  #14  
Old 04-15-2019, 10:28 PM
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Thank you guys for all the advice. I will definitely being doing a fluid flush on the ole truck this weekend.
 
 


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