Power Steering Deep Dive

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kcmash

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OK, it's time to go deep in the power steering as I came close to losing my car yesterday.

What I have:

Rebuilt Ford power steering pump from Dorman, and  a rebuilt variable ratio power steering box from Power Steering.com

When I put this together I have had a little "float" to my steering at center.  It takes a lot of wheel jockeying to keep it in the center of the lane.  It actually had a few times that it felt like it wants to power to the left when I start right. (just for a microsecond or so).  I also had some slight groaning in the pump.  Since I got the carb tuned yesterday and was having better luck with idle I decided to try a closer look at the Power Steering issue.

Upon return from a drive, the car was warm and I attempted to go stop to stop on the steering.  I went all the way to the right and attempted to turn left, but it was super tight.  I saw my engine idle had dropped so i I gave it a little throttle to help the pump then "POW" the high pressure hose blew out of the ferrule clamp down at the steering box.  PS fluid all over that ignited on the hot exhaust.  Me realizing I don't know how to get that fire out,(Its a long way down there in our engine bays). Luckily it was the fluid burning on the manifold, and the fire did not seem to damage much else. ( I had to use water to put the fire out)

So I can put another power steering hose on and clean the engine bay, but I want to know what the hell is going on.  I have heard of others blowing a power steering hose on this forum.  This has never been a problem in the 40 years I have owned the car.

1) Marty at power steering. com thought I may have too high of pump pressure when I told him of the center floating issue.  My question, how did Ford make sure no Mustangs had high pressure with these pumps?

2) Does it sound like I have a steering box issue?  I am glad this happened inn the driveway, but I just need this to work and not be a risk.  Thanks goodness this didn't happen at a cruise night!

3)  What do you suggest I do?  I am perplexed!  Is there a way to dial down pump pressure?  Are these reproduction High pressure lines with the shock tower loop poor quality?  Did I simply have an air bubble in the system that caused the problem?(Not likely with the couple hundred miles I have on it.)

Thanks for the input.

kcmash

 
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I had a problem with what you are describing about the float when trying to go straight. It was after I got a front end alignment. It turned out to be a bad pitman arm. Replaced that and my steering has been great ever since. I also had replaced the long original power steering hose with a new “concourse” one. Well, that one didn’t last very long till it did the same as yours. It blew while I was trying to make a sharp turn and I almost hit another car and it made one hell of a mess. Was lucky enough that it didn’t catch fire. Anyway I just got another long hose and it has been fine ever since.

Sorry not much help, but check out your pitman arm and the other steering components to make sure nothing is loose or worn out. 

 

kcmash

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JPAZ,

Good reminder.  I think it was your post I was thinking of.

I have a new Pittman arm along with all other components on mine,  so I eliminated that one.
 

I do have another pressure hose without the long service loop new in the garage.  I may try that with another system bleed and see what happens.

kcmash

 
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Just my thoughts on this. The HP hose I have is from NPD, not concours, just a long tube replacement. Been on since I converted to PS without problem. In the PS box, there is a one way valve of sorts under the HP connector brass insert. I think that may be the problem. If it has stuck or inserted incorrectly, that would cause the over high pressure because the fluid cannot circulate, so that would blow the hose. I've rebuild a couple of V/R PS boxes and if that little valve is not put in right. I believe it would likely cause your problem.

Our friend Bentworker has done way more PS boxes then me, he may have a better idea of the issue.

Just because it was built by so called professionals, doesn't mean it's right. That how and why I learned to do my own PS rebuilds. The "pro" that did my first, could have killed me!

Just had another thought and this happened to mine, but did not blow anything. The rotation valve in the valve body was sticking. I had power to one side, but not the other. The only option was to find another V/R box and replace the valve and hope it worked. I got lucky, buying a complete PS box from OMS that was good. You may want to send that box back to where it came from to be checked and repaired.  Something isn't right for sure. 

 
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Bentworker

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My understanding is the pump contains the pressure regulator.  If you held your steering wheel at full lock and popped a hose I’d say the pump is in need of some work as the pressure regulator must be no good.  Also your comments about pump noise do not seem promising. My suggestion would be to try a different pump. 
 

I know very little about the Ford style pumps.  The Saginaw “canned ham” style pumps are very easy to adjust max flow and pressure.  If you were to swap to the Saginaw pump I could point you in the right direction.  If not I am sure you could geek out and adjust a ford pump, but you would have to research it for yourself.

Before going down the path of calling out the steering box as the problem what are your caster and toe alignment numbers?

 

kcmash

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Well, I dont have alignment numbers,  I did a string and protractor alignment during restoration,  took it to a shop and they said the numbers looked good and they wodnt change a thing.

I was only at the stop for a second before she locked up.  Is there a way to check the rotation valve?

Kcmash 

 

Bentworker

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I don’t know if there is a practical way to check the valve without a test bench gizmo that steering shops have..  You could plumb a 2000psi pressure gauge in the pressure line and see what is going on.  The pressure should be low when there is no force being applied to the steering wheel (20- 150 psi?)  The valve should be porting oil from the pressure to the return port.  Once you give the steering wheel a turn one way or the other you should see the pressure come up a bit as the valve is porting oil to one side of the piston or the other.  How high it goes would depend on what kind of surface the car is on and how wide the tires are.  When you hold the steering wheel at full lock the pressure should jump up to whatever the relief is set at on your pump.

 
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My understanding is the pump contains the pressure regulator.  If you held your steering wheel at full lock and popped a hose I’d say the pump is in need of some work as the pressure regulator must be no good.  Also your comments about pump noise do not seem promising. My suggestion would be to try a different pump. 
 

I know very little about the Ford style pumps.  The Saginaw “canned ham” style pumps are very easy to adjust max flow and pressure.  If you were to swap to the Saginaw pump I could point you in the right direction.  If not I am sure you could geek out and adjust a ford pump, but you would have to research it for yourself.

Before going down the path of calling out the steering box as the problem what are your caster and toe alignment numbers?
Good points Bentworker. I had a feeling you might have a better idea of what might be going on. I have personally not worked on the pump, that was the only thing the "pro" I sent mine stuff to, did right.

 

Hemikiller

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The pressure regulator is internal to the pump. If it's sticking or jammed, then it could blow the hose off. Seal kits are only a couple bucks, so I'd dig into that soonest. 

FWIW, the specs the shops are going by will be the factory spec, which are no good for radial tires. There needs to be extra caster dialed in to get rid of the "float" on center. 

 
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FWIW, the specs the shops are going by will be the factory spec, which are no good for radial tires. There needs to be extra caster dialed in to get rid of the "float" on center. 
 I'm a bit late to the party on this one, but I thought I would add the latest alignment numbers that seem to work quite well on my car with 235-60 R14 BFG radials up front. 

Caster; +3 degrees each side. Camber; Left -0.5, Right -0.8 deg. Toe; left and right, -1/16, total -1/8"

The caster was as much as could be put in without interference with stock suspension components. I might have liked it to be slightly more, but it is what it is.

 
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kcmash

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Thanks for the alignment numbers Stanglover.

Today I pulled the PS box back out and sent it off to Power Steering .com to have it looked over again.  Hopefully that will be a quick turnaround.

I also called National Parts depot where I bought the High Pressure Hose from that failed.  I let them know that I felt these were not up to quality standards.  They will get the case on the managements desk on Monday.

I also ordered new bushings for the equalizer bar as that has some play in it that may be giving me some problems.

 

Bentworker

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Thanks for the alignment numbers Stanglover.

Today I pulled the PS box back out and sent it off to Power Steering .com to have it looked over again.  Hopefully that will be a quick turnaround.

I also called National Parts depot where I bought the High Pressure Hose from that failed.  I let them know that I felt these were not up to quality standards.  They will get the case on the managements desk on Monday.

I also ordered new bushings for the equalizer bar as that has some play in it that may be giving me some problems.
What did you decide to do with your pump?

 

kcmash

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Wow, I thought I replied to this.  

For the pump, I am unsure what to do.  I have watched some videos on how to rebuild the pump, but saw nothing to adjust, no relief valve, etc.  So aside from tearing it down and hoping I can re-assemble properly I am unsure what value I would add.  

I still have my original pump, I guess I could put a new seal kit in that.  I replaced it because it seemed weak after restoration.  I actually had the power assist coming and going in and out.  I am shocked that this is so complex to dial in.  I know Ford had to meet safety standards, so these should be able to come together and work.

Do you have a link to any good articles or videos on the pump that I should look into?

kcmash

 

kcmash

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So I downloaded the Ford Thompson power steering pump manual and looked through it.  The only situations they define for pump pressure are “insufficient pressure”. Which can be caused by wear, contamination, or clogged ports.  There are no conditions for high pump pressure.
 

my thoughts right now are:

1) Defective crimp on the power steering hose.

2) Clogged relief valve in the steering box

3) alignment not correct for radial tires.

Pump manual: https://www.fordification.com/tech/PDF/FordPSpump-diagnosis.pdf

kcmash

 
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So I downloaded the Ford Thompson power steering pump manual and looked through it.  The only situations they define for pump pressure are “insufficient pressure”. Which can be caused by wear, contamination, or clogged ports.  There are no conditions for high pump pressure.
 

my thoughts right now are:

1) Defective crimp on the power steering hose.

2) Clogged relief valve in the steering box

3) alignment not correct for radial tires.

Pump manual: https://www.fordification.com/tech/PDF/FordPSpump-diagnosis.pdf

kcmash
Thanks for the download link. I have saved that for future reference.  The pump is something I have NOT played with yet. As for the PS box, you said you'd sent that back for inspection and possible re-rebuild. It could be the h/p valve not in correctly or it could simply be that the h/p hose you happened to get, was defective from the get-go. There is something like 1500psi going through that if I remember right without checking, so a blow out on a bad hose is a real possibility. Anyway, it's a real PITA for sure, hope you get it sorted very soon.

 

Bentworker

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So I downloaded the Ford Thompson power steering pump manual and looked through it.  The only situations they define for pump pressure are “insufficient pressure”. Which can be caused by wear, contamination, or clogged ports.  There are no conditions for high pump pressure.
 

my thoughts right now are:

1) Defective crimp on the power steering hose.

2) Clogged relief valve in the steering box

3) alignment not correct for radial tires.

Pump manual: https://www.fordification.com/tech/PDF/FordPSpump-diagnosis.pdf

kcmash
Another resource.

http://www.stangerssite.com/HowItWorksFordPump.html
 

Something I want to make clear is that to the best of my knowledge there is NO relief valve in the steering box itself. I believe your conclusion #2 to be impossible.

The only pressure regulating part in the entire hydraulic circuit is inside the pump.  If there is a max pressure problem- it is inside the pump.

The alignment is probably contributing to the steering feel issue.  I’m curious what your alignment numbers currently are.

ABF2F4DD-00EF-4491-B3ED-A19028ABAD78.jpeg

 
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To be fair, I should have caught that, but I understood what was being described. It is not a pressure relief valve, but it is a Check Valve. 

When I was installing new  brass seats, I did get a "check valve' in not straight and it caught up. It just needed a slight wiggle to get it in properly. I doubt that would have happened and caused the problem in this case. unless the valve 'plate' for want of a better description, was put in upside down and even that would be a stretch to imagine. Here's a scan of the exploded view of the PS box. Check valve and seats circled.

View attachment Exploded view PS box.pdf

 

kcmash

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Stanglover,  do you know what the adjustment plug does in the exploded view you provided?

Bentworker,  thanks for the view on the pump relief valve.  I did not see any way to service that in the service manual I posted.  Everything I saw was for low pressure, making me think that valve is a simple spring control that should never go high.

The pump I put in is a Dorman through Rock Auto.  I assume the Dorman stuff has been pressure tested.

What do you guys suggest?  Get a pump kit and reseal my original?

kcmash

 
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Stanglover,  do you know what the adjustment plug does in the exploded view you provided?

Bentworker,  thanks for the view on the pump relief valve.  I did not see any way to service that in the service manual I posted.  Everything I saw was for low pressure, making me think that valve is a simple spring control that should never go high.

The pump I put in is a Dorman through Rock Auto.  I assume the Dorman stuff has been pressure tested.

What do you guys suggest?  Get a pump kit and reseal my original?

kcmash
You are refering to the "Adjuster Plug" correct? It is to set the pre-load on the thrust bearing at the bottom of the rotation valve. Here are a couple of pic that may help explain. This should already be set by whomever rebuilt your PS box and need not be touched...... unless it too was not set correctly. I have spent considerable time learning how to rebuild these boxes and I'm no where near knowing all about them, but I have now successfully rebuilt 3 variable ratio boxes for my own use.

1st pic, valve assembly and adjuster plug (threaded bit) 2nd pic, My adjuster plug wrench. 3rd pic, plug tightened then backed off 1/2" in pic #4. 5th pic, correct preload in In/lbs.

IMG_0760-1.JPG

IMG_0761-1.JPG

IMG_0763-1.JPG

IMG_0764-1.JPG

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