Power steering fail!

Discussion in 'Chassis' started by swiftkid, Feb 18, 2018.

  1. swiftkid New Member

    Joined:
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    Hi all,

    So long story here, my mate has done a good tidy up on his Corrado VR6 and had engine out, all nice shiny powder coated bits, replaced a load of bits and got reconditioned others. Rebuilt it back up and power steering was not working, at all. Not even the whine they usually make.

    So, to date he's replaced
    -the rack, with a reconditioned unit, which he sent back and got another that was checked
    -all pipework
    -he's had a new pump, my old pump (that 100% worked), a mk4 pump and another one yesterday

    We've done all the recommended bleeding techniques, lock to lock with engine off, then lock to lock with engine on. We've cracked all the pipes to try manually get all the air out if there is any.
    So yesterday seemed like a breakthrough, replaced the pump for yet another one and bled the system, turned it on and hey presto power steering! But after we had continued bleeding to be safe, it stopped working. We decided to take the old (brand new) unit apart and noticed the pressure relief valve was stuck retracted, so cracked the high pressure line off and on the one fitted the pressure relief valve was also stuck down. Gave it a prod and it shot back out, bolted it all back together and fired it back up, it worked for another few minutes then stopped again.

    So my question is, what fuel would you use to set the car on fire?

    He said it originally came with green fluid, he has since flushed it completely and replaced with red fluid as recommended, the power steering reservoir has a red cap so seems to be correct. I understand how the pressure relief valve works but what would cause it to stick? couldn't find any grit in the one we removed, if there was an airlock/obstruction in the pipe it would cause the pressure relief valve to open but should it just release itself once pressure has dropped?

    Anyone got any advice?
     
  2. abf"d mk1 Paid Member Paid Member

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    cambridgeshire
    Petrol, and move it away from any other parked cars first.
     
  3. rubjonny

    rubjonny Administrator Staff Member Admin

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    usually you should keep to whatever fluid the steering rack had in it originally, mk2 golf tend to use the red Dexron II ATF stuff but later corrado would be green as your mate said it originally had.

    though my understanding was the worst case the rack may start leaking, and a reconditioned unit would be fine with either? not sure why your pump valves are all sticking like this...

    certainly red fluid is no problem with later pumps I've built a few MK2 conversions using mk3 power steering pumps and always used red fluid if it has a mk2 rack on it. including my own car which has been running a recon mk2 rack & pipes plus mk3 pas pump on red fluid for the last 12 years!

    have a good look at the pipework, maybe one has a kink which is increasing pressure in the system? The fluid return can sometimes have a restrictor in it which affects the steering assistance, thats worth a look. Mine is just a straight pipe from rack to reservoir with no restrictor in it that I know of. Nige has soem info in his build thread, plus he has put an extract about it in here:
    http://clubgti.com/showthread.php?262033
     
  4. swiftkid New Member

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    Yes, I had read not to swap fluids but thats already happened! I thought it the other way round though? I.e. green for early, red for later?

    We have had a right good look around the pipework but he's actually changed the pipework already which is the strange bit.

    I was under the impression red is a heavier grade, which theoretically if there was some form of restriction (not purposeful) would definitely help in causing the pressure relief valve to open. My confusion is why wouldn't the valve close again once pressure is released. I've told him to try flushing the system and trying green fluid if it is the lighter of the 2.
     
  5. rubjonny

    rubjonny Administrator Staff Member Admin

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    red is up to 90ish, then vw switched to green :)

    as i say ive had red in my mk2 for years with a mk3 golf pump (which should run on green) never had an issue with it so fluid shouldnt be causing your issue regardless. very strange one!
     

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