power steering noise

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73 mach1, medium blue, 351 C-6
power steering pump makes a loud squeal starting at 2000 rpm. pump and steering box was rebuilt at a rebuilder with lifetime warranty. the first rebuild they installed a fast ratio in box, think it was 12.5 to 1. everything was good until box started to leak, sent it back and was fixed and shortly after, this noise started. sent pump back and was checked out, said they found nothing wrong. sent box back, ratio was changed to 14 to 1, thinking pump flow was the problem. 14 to 1 ratio caused loss of steering while turning sharply. in the meantime i bought another pump at a parts store, installed it, same noise. sent box back again, ratio was changed to 16 to 1, no luck. high and low pressure lines have replaced. changed water pump pulley to bypass power steering pump, that way i had one belt running water pump and alternator only, drove car noise gone. dont know what to do now to fix, other than to ask for my money back, and find someone else to rebuild steering box. any ideas or suggestions? i dont know if i can say who was the rebuilder on here
 
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1971 Mustang Mach 1, M code, 4 speed.
Well, I'm far from an expert on this, but I have rebuilt a couple of PS boxes myself with good results. Mine are variable ratio 16 / 13:1.
It make little sense to me why the rebuilder would just go the route of changing the ratio, rather than finding out why. The first component I would look at within the box, is the rotation valve or spool valve as it's also called. I had one of these that wore out and I lost power to the right side. There is no point in me getting too far into this, but if you changed the pulleys to bypass the pump and the noise stopped, then it isn't the PS system. I would however question what pulley you have on the water pump as well as the pulley you have on the PS pump. They have to match. Just because it's a pulley, doesn't mean it's right. You could be turning the PS pump at the wrong speed, as well as the water pump. Find out the correct part numbers for your car as well as the crank pulley. My car was converted from manual to power steering and I had to source a crank pulley as well as water pump. The ps pump came off a 71 Mach 1 and was correct.
Going back to the PS pump, there is a video on NPD's website I found under "Power steering pump". It's a bit cheesy, but in it, the one guy says he ground the surface of the front plate by only .0005", and then the pump squealed. As I'm also about to rebuild a pump or maybe just replace it, I took note of that.
Our friend Bentworker has rebuild several boxes adding fast ratio components. He nay have a better idea as to why.
 
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Upstate NY
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71 Mach 1, 351c 4v, C6 trans, grabber blue with white interior
A few of us have used PowerSteering.com for pump and steering box rebuilds with good luck. Dont know if he was the one you used but he seemed good so hopefully it wasnt him.
Always good to know bad vs good companies to deal with.
 
Joined
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73 mach1, medium blue, 351 C-6
A few of us have used PowerSteering.com for pump and steering box rebuilds with good luck. Dont know if he was the one you used but he seemed good so hopefully it wasnt him.
Always good to know bad vs good companies to deal w rebuilt the box and pump
they rebuilt the box and pump
 
Joined
Dec 3, 2017
Messages
87
Reaction score
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Location
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My Car
73 mach1, medium blue, 351 C-6
Well, I'm far from an expert on this, but I have rebuilt a couple of PS boxes myself with good results. Mine are variable ratio 16 / 13:1.
It make little sense to me why the rebuilder would just go the route of changing the ratio, rather than finding out why. The first component I would look at within the box, is the rotation valve or spool valve as it's also called. I had one of these that wore out and I lost power to the right side. There is no point in me getting too far into this, but if you changed the pulleys to bypass the pump and the noise stopped, then it isn't the PS system. I would however question what pulley you have on the water pump as well as the pulley you have on the PS pump. They have to match. Just because it's a pulley, doesn't mean it's right. You could be turning the PS pump at the wrong speed, as well as the water pump. Find out the correct part numbers for your car as well as the crank pulley. My car was converted from manual to power steering and I had to source a crank pulley as well as water pump. The ps pump came off a 71 Mach 1 and was correct.
Going back to the PS pump, there is a video on NPD's website I found under "Power steering pump". It's a bit cheesy, but in it, the one guy says he ground the surface of the front plate by only .0005", and then the pump squealed. As I'm also about to rebuild a pump or maybe just replace it, I took note of that.
Our friend Bentworker has rebuild several boxes adding fast ratio components. He nay have a better idea as to why.
changed pulley on water pump to align with alternator, to run one belt. took belt off steering pump. that way i know that the water pump and alternator was not the problem. pulley on steering pump was on car when i bought it and had no problems untill i had everything rebuilt. i have another 351c and the crank pulley and ps pulley are the same size. the pulley i used on the water pump was a temporary measure to help diagnose the problem
 
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KevinP

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1972 Q-code Mach1
What fluid are you using. Only one that works without noise is type F
 
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update: changed pump over to saginaw p pump, from cvf racing and brackets. flushed gear box now running power steering fluid. noise gone. saginaw pump puts out 1200 psi, was told ford pump puts out 1200 psi, so if psi on both pumps are the same, only thing thats changed is the fluid, or maybe the flow of the pumps. dont know and dont care, just glad its fixed.
 
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