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Discussion Starter · #1 ·
Hey guys, I have an 08 f250. 3 times I have replaced my hydroboost since November of last year and it looks like I'll have to do it again. Original replaced in November 2020 leaking between boost and master. Replaced that one in August 2021 leaking between the 2. Replaced that one last week leaking again from between the boost and master. Now this one is leaking at the same place barely a week after replacement. This will now be the 4th one in less than a year 3rd one in the last 2 months. They have all been remanned since the original i purchased was that and I exchanged the part under warranty each time so far. Am I having a pressure issue from the pump? Is that a possibility? What could cause this multiple times now? Any help is greatly appreciated.
 

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Hey guys, I have an 08 f250. 3 times I have replaced my hydroboost since November of last year and it looks like I'll have to do it again. Original replaced in November 2020 leaking between boost and master. Replaced that one in August 2021 leaking between the 2. Replaced that one last week leaking again from between the boost and master. Now this one is leaking at the same place barely a week after replacement. This will now be the 4th one in less than a year 3rd one in the last 2 months. They have all been remanned since the original i purchased was that and I exchanged the part under warranty each time so far. Am I having a pressure issue from the pump? Is that a possibility? What could cause this multiple times now? Any help is greatly appreciated.
A pump provides flow not pressure. Max flow is just off idle. It’s likely you have a sealing issue with the master. Is it ps fluid leaking or brake fluid leaking? You get pressure when the wheels are turned and the torsion rod in the steering gear deflects and sends fluid to the piston.


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Discussion Starter · #4 ·
A pump provides flow not pressure. Max flow is just off idle. It’s likely you have a sealing issue with the master. Is it ps fluid leaking or brake fluid leaking? You get pressure when the wheels are turned and the torsion rod in the steering gear deflects and sends fluid to the piston.


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Ah ok. That makes sense. Its PS fluid. It's leaking from the weep hole every time.
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Did you replace the O-rings on the ends of the 2 supply lines? That could be a source of the leaks.

Yes I did that. Not sure exactly thou how that would make it leak from between the hydro and the master.
 

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A pump provides flow not pressure. Max flow is just off idle. It’s likely you have a sealing issue with the master. Is it ps fluid leaking or brake fluid leaking? You get pressure when the wheels are turned and the torsion rod in the steering gear deflects and sends fluid to the piston.
Nope.
A vane type pump like the power steering pump provides BOTH flow and pressure. Flow increases pretty much proportional to pump speed, increasing as speed increases, and pressure depends on how much resistance there is to flow. Vane type pumps are close to positive displacement and flow is reduced below theoretical by how much leakage there is past the vanes. Some pumps have a pressure relief system to prevent excess pressure. On the steering system, the pressure and flow are controlled by the steering gear. When the wheel is straight, flow and pressure are bypassed back to the pump reservoir. When the wheel is turned, the torsion rod opens a valve to direct pressure and flow to the piston to assist turning the wheels.

Leakage between the hydroboost and master cylinder could be from either unit.
 

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It's definitely coming from the hydro boost and not the master. This is the 4th one that has done it. Having to replenish PS fluid every couple days.
Check the seals internal or maybe you have a restriction in your system causing too much pressure in the system. Since your a recirculating ball system I’d lean towards the steering gear and or lines. A pump only provides flow. Not pressure. The valve in the steering gear provides pressure. Should hook up a pressure gauge from the outlet of the pump and steering gear and see what the pressure is like.


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Could be pressure relief in the steering gear or piping has bee installed incorrectly at some point. Been a while but as I recollect flow is from the pump to hydroboost then to steering gear with a return from each to reservoir. When you bottom your steering gear in either direction pressure is limited by pressure relief in steering gear. (The hissing sound you hear) The pump creates flow but any resistance to that flow creates pressure. With brake and steering in neutral position flow circulates with no resistance other than frictional. I install one years ago but really haven't been around one since. You might want to reference some technical literature
 
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