Bowie69 Posted September 28, 2011 Author Share Posted September 28, 2011 Well,in a bit of a rush, I have swapped over to hydraulic fluid, but due to phone calls etc, not managed to bleed it all out properly yet, but the fluid is now golden coloured, rather than pink/red When flushing, I first flushed the reservoir, by dropping the return hose off, then ran the engine until fluid stopped coming out of the return (a very short time!). Next I topped the reservoir up with HF and ran it up thinking that should do it, then had a thought and realised the box would basically remain full of ATF, so fitted a small hose to the box bleed nippe and opened it up while I topped up the reservoir until it ran clear, plus turned the steering back and forth a couple of times. The stuff in the reservoir is now clear, if a little foamy. I have left it to settle for a while, and will go back and bleed properly shortly. Agreed on the ID of the steel pipe, was been rather dim this morning Quote Link to comment Share on other sites More sharing options...
landy V8 Posted October 1, 2011 Share Posted October 1, 2011 just put mine back together after doing other bits to it as well. opened my port out to 3mm.i'm running 35" tyres on mine and it has made it effortless to turn the steering.even at a standstill it can be turned one-handed.still using normal atf/steering fluid. well happy. Quote Link to comment Share on other sites More sharing options...
landybehr Posted October 2, 2011 Share Posted October 2, 2011 I wonder if the PAS-steering box is rated to much higher pressures. On pirate4x4 people use steering boxes from other makes and corresponding pumps. Those, IIRC from the threads there, deliver somewhat around 30% more pressure than the pump that Rover supplied f.e. with my RRC. I have no concrete idea of what will happen when a steering box is kind of overloaded. You don´t always call for the maximum assistance when steering, unless at full lock or when the tires are very difficult to turn. In these conditions I could imagine the seals could suffer. Quote Link to comment Share on other sites More sharing options...
RangeyRover Posted October 3, 2011 Share Posted October 3, 2011 I wonder if the PAS-steering box is rated to much higher pressures. On pirate4x4 people use steering boxes from other makes and corresponding pumps. Those, IIRC from the threads there, deliver somewhat around 30% more pressure than the pump that Rover supplied f.e. with my RRC. I have no concrete idea of what will happen when a steering box is kind of overloaded. You don´t always call for the maximum assistance when steering, unless at full lock or when the tires are very difficult to turn. In these conditions I could imagine the seals could suffer. I don't think that pressure is being altered here. The effect of opening the port is surely to increase flow, not pressure? Otherwise we would be talking about changing the strength of the spring in the PRV? Or am I being thick? Only on first coffee so possible.... Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 3, 2011 Author Share Posted October 3, 2011 Agreed RangeyRover, that's my understanding of it. On Pirate I have since found many threads relating to modifying the PRV, but as my RR P38 pump is already 1500PSI, and that's what the Pirate bodgers are aiming for, I didn't see the point, hence the 'opening up' title to this question. Still not had a chance to look further at mine, but looks like someone has had some success! Quote Link to comment Share on other sites More sharing options...
landybehr Posted October 8, 2011 Share Posted October 8, 2011 that I´m wrong that´s good news. I might remember that mod when I come close enough the the PAS pump in my car Quote Link to comment Share on other sites More sharing options...
dirtyninety Posted October 27, 2011 Share Posted October 27, 2011 Is there an update for this thread, I would really like to hear Bowie69's results! I have mine drilled out (200tdi) to about 8mm, dry steering on concrete with 35" simex is a one finger operation. lots of bubbles, so swapping out to hydraulic oil tonight hopefully. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 27, 2011 Author Share Posted October 27, 2011 Sorry, no final results so far, apart from using up about 3l of hydraulic oil! Still cavitating as far as I can work out, but then I have had zero time to work on it recently, or rather the jobs I needed to get done were more important than this! 'Landy V8' above has had success though, if you read above a few posts Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted November 2, 2011 Share Posted November 2, 2011 How big can you go without modifying the PAS system then? Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted November 2, 2011 Author Share Posted November 2, 2011 WELL... I only started cavitating at 5mm (stock is 3.2mm), but bear in mind this is on a P38 PAS pump, not the regular RRC pump, and no idea how it compares to the one DD is running. If you have a spare pump there's no harm in trying, the port unscrews easily enough with a 27mm socket. Quote Link to comment Share on other sites More sharing options...
Range Rover Blues Posted November 5, 2011 Share Posted November 5, 2011 One more thing on the list of stuff to do when i get a day off then............................................. Quote Link to comment Share on other sites More sharing options...
Bowie69 Posted October 17, 2016 Author Share Posted October 17, 2016 As a very late update, I went back to 4.5mm which gives a nice improvement vs a problem with cavitation and needs for coolers and special oil. I still run the VG32 hydraulic oil, over the ATF, no real issues with this, though I suspect I could get away with ATF at 4.5mm. Remember the volume will go up with the square of the change, so 3.2mm to 4.5 mm is a big jump -8mm2 to 16mm2, so at least twice the volume. Also remember the P38-style serpentine pump is higher pressure than the older style pumps, at 1500PSI, so no need to open up so much when feeding a 4-bolt box. Quote Link to comment Share on other sites More sharing options...
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