Berlingo 1.4i 2004
I have a power steering problem, hardly even noticed it before and it never really bothered me.
But the MOT guys did notice and got hung up on it and I barely managed to talk my way out of it, may not be so lucky next time.
First: do all these cars have this problem (can you check yours) ? No point in searching for a faulty part if it was created like this at the factory...
The problem is not noticeable when driving normally (little or no assist required), but becomes gradually more noticeable as
more assist is required. I start to notice it at walking speed, much worse when parked on gravel, and worst when parked on
hot asphalt, when the most assist is required.
The stick-slip is the same in any direction or position, left or right, as long as there is high demand for assist. Also it is independant of engine RPM.
If the engine is off there is no trace of the problem, the steering wheel is moving smoothly from lock to lock so this excludes any mechanical problem with rack bar, joints and bearings etc. Looks to me as a purely hydraulic problem.
Replaced all seals in the pinion valve, including the 4 Teflon rings, problem persists.
So now we're pretty much left with the pump...
All PS pumps I have tinkered with have had 2 valves and springs:
the pressure/flow regulating valve (spool valve), and
the over pressure bypass valve. Its only purpose is to prevent blowing seals and hoses and breaking the pump shaft.
But this pump has a 3rd valve and spring, located in the fitting where the HP pipe connects.
I have no idea what this valve is for or how/why it moves. It is spring-loaded with a weak 20-50g spring. Once this
valve got stuck so the spring could not return it (probably galling), this resulted in almost total loss of assist.
The valve is pressed together so cannot be disassembled, but I managed to free it using Autosol and a drop of oil.
When moving the steering wheel in only one direction all is fine, but backing off just 1 degree results in a "jerk" or jump or servo over-correction, as if the pump pressure suddenly drops off too much...
See video demonstrating the problem here: https://www.youtube.com/watch?v=otGqYEyfEW4
Some additional info. Image: Top 2 is my valve, bottom is what other pumps have; no valve.
PDF: Valve operation in typical 2-valve pump
Anyone have an ide of whats going on with my steering ??
I have a power steering problem, hardly even noticed it before and it never really bothered me.
But the MOT guys did notice and got hung up on it and I barely managed to talk my way out of it, may not be so lucky next time.
First: do all these cars have this problem (can you check yours) ? No point in searching for a faulty part if it was created like this at the factory...
The problem is not noticeable when driving normally (little or no assist required), but becomes gradually more noticeable as
more assist is required. I start to notice it at walking speed, much worse when parked on gravel, and worst when parked on
hot asphalt, when the most assist is required.
The stick-slip is the same in any direction or position, left or right, as long as there is high demand for assist. Also it is independant of engine RPM.
If the engine is off there is no trace of the problem, the steering wheel is moving smoothly from lock to lock so this excludes any mechanical problem with rack bar, joints and bearings etc. Looks to me as a purely hydraulic problem.
Replaced all seals in the pinion valve, including the 4 Teflon rings, problem persists.
So now we're pretty much left with the pump...
All PS pumps I have tinkered with have had 2 valves and springs:
the pressure/flow regulating valve (spool valve), and
the over pressure bypass valve. Its only purpose is to prevent blowing seals and hoses and breaking the pump shaft.
But this pump has a 3rd valve and spring, located in the fitting where the HP pipe connects.
I have no idea what this valve is for or how/why it moves. It is spring-loaded with a weak 20-50g spring. Once this
valve got stuck so the spring could not return it (probably galling), this resulted in almost total loss of assist.
The valve is pressed together so cannot be disassembled, but I managed to free it using Autosol and a drop of oil.
When moving the steering wheel in only one direction all is fine, but backing off just 1 degree results in a "jerk" or jump or servo over-correction, as if the pump pressure suddenly drops off too much...
See video demonstrating the problem here: https://www.youtube.com/watch?v=otGqYEyfEW4
Some additional info. Image: Top 2 is my valve, bottom is what other pumps have; no valve.
PDF: Valve operation in typical 2-valve pump
Anyone have an ide of whats going on with my steering ??
![[-]](http://berlingoforum.b-cdn.net/images/collapse.png)
