ajh Posted June 2, 2011 Share Posted June 2, 2011 I'm having some issues fixing a 93 RRC and would appreciate some insight/assistance. The brake booster pump has been rebuilt, seems to generate pressure but does not shut off at any point and I tried two different pressure switches. The ABS code showing is a 3-9, could this be causing the pump to never shut off? What is the most likely cause for a 3-9 "ECU connection or wiring to outlet, isolating, hydraulic motor solenoid valve"? Quote Link to comment Share on other sites More sharing options...
Snagger Posted June 2, 2011 Share Posted June 2, 2011 My '95 has a Wabco brake system with power brakes, ABS and (rear) ETC. I suspect it's the same system as yours. Ever since having the brake system professionally bled (it's trickier and has a specific technique compared to non-ABS/powered systems) following my rebuild of the callipers, the red brake warning light stays on with the compressor much longer than before, keeping the ABS and ETC lights illuminated with it. I think it's the accumulator and compressor that need bleeding - they weren't done with the rest of the system (I was informed at the time that they wouldn't need it). Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted June 3, 2011 Share Posted June 3, 2011 A bit of googling has turned up that it could potentially be a stuck relay (wasn't clear about were the relay was) - no more information than that, though, so I'm not sure how much use it is Quote Link to comment Share on other sites More sharing options...
Fett Posted June 3, 2011 Share Posted June 3, 2011 I think they are under one of the front seats. it can take up to 11 litres of fluid and a lot of time and mess to bleed one of the classic systems Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted June 4, 2011 Share Posted June 4, 2011 The ABS controller is under the left hand front seat, there are some associated relays there, but what I don't know is where the relay that might (possibly...) be sticking is - separate one under the seat? In the controller? Maybe even on the block itself? Classic system takes a while to bleed and is almost impossible without two people, but as long as you methodically follow the workshop manual it's not that hard. Quote Link to comment Share on other sites More sharing options...
pitcaig Posted June 5, 2011 Share Posted June 5, 2011 I think they are under one of the front seats. it can take up to 11 litres of fluid and a lot of time and mess to bleed one of the classic systems I've not long replaced all the brake pipes and hoses on my RRC 1994 ABS and only used about 2litres of fluid. It has since past its MOT with flying colours Quote Link to comment Share on other sites More sharing options...
ajh Posted June 6, 2011 Author Share Posted June 6, 2011 This is just getting stranger. HELP! I bled everything and it seems to be fine EXCEPT... if I block the outlet of the brake-boost pump the pressure switch turns it off almost right away which is as it should be. If I connect it to the accumulator then the pressure never builds which to me means that it's flowing though into the TC/ABS modulator and circulating unimpeded... there is 3-9 code showing as well. Does this indicate a broken value inside the modulator? Any other ideas? I strongly suspect if I blocked off the other port on the accumulator with a bleed screw then it would store pressure fine.. it's just leaking through somewhere and I'm staring to lose it. Quote Link to comment Share on other sites More sharing options...
Roverbo Posted June 7, 2011 Share Posted June 7, 2011 This is just getting stranger. HELP! I bled everything and it seems to be fine EXCEPT... if I block the outlet of the brake-boost pump the pressure switch turns it off almost right away which is as it should be. If I connect it to the accumulator then the pressure never builds which to me means that it's flowing though into the TC/ABS modulator and circulating unimpeded... there is 3-9 code showing as well. Does this indicate a broken value inside the modulator? Any other ideas? I strongly suspect if I blocked off the other port on the accumulator with a bleed screw then it would store pressure fine.. it's just leaking through somewhere and I'm staring to lose it. Hi ajh, yes, i think that your controlblock could be defect; every component in that system could be defect, the problem is that they are so hard to test. I once bought a complete set of (used) ABS components for my 1990 RRC, and a friend bought the controlblock from me to fix his system (he had problems similar to yours). What really wonders me about these systems, is where the pressured fluid goes, when it "disappears" (pressure drop)?. I changed the accumulator two wears ago, because the pump was running every, say, two minutes. The new accu changed that to every five minutes; but now i´m back to once a minute - I find it hard to believe that an original Wabco-part fails that fast. So now my suspicion lies on the non-return valve in the pump. Well, not a great help to you, maybe.... try to block the other port on the accumulator first, to rule that out. Quote Link to comment Share on other sites More sharing options...
ajh Posted June 8, 2011 Author Share Posted June 8, 2011 So, anyone got a working ETC equipped control block they want to sell cheap? This customer doesn't really have any income to speak of and has just been trying to get the RRC on the road for about 3 months (I got it about a month ago). Quote Link to comment Share on other sites More sharing options...
Roverbo Posted June 8, 2011 Share Posted June 8, 2011 So, anyone got a working ETC equipped control block they want to sell cheap? This customer doesn't really have any income to speak of and has just been trying to get the RRC on the road for about 3 months (I got it about a month ago). Sorry, can´t help you...but have you read the official manual? I have put it here My link. It does not cover the ETC, but the components are identical, except for the programming of the ECU. The only fault described that causes the pump to run constantly is "non-return valve in pump defect". As I am on my second pump now, and looking for a third, I tend to think that there are different stages of "non-functioning" valves. Could be, that the harsh pressure-build up with the outlet blocked could trigger the valve and pressure switch, but a slower increasing pressure could not. Logically seen, what has changed in your system: The pump. Where to seek the error: The pump. Who did the repair, and what was done? Regards Bo Quote Link to comment Share on other sites More sharing options...
geoffbeaumont Posted June 9, 2011 Share Posted June 9, 2011 It does not cover the ETC, but the components are identical, except for the programming of the ECU. From memory, there are actually a couple of extra valves in the block for ETC, not just software changes. Quote Link to comment Share on other sites More sharing options...
Roverbo Posted June 9, 2011 Share Posted June 9, 2011 From memory, there are actually a couple of extra valves in the block for ETC, not just software changes. Sorry, you´re right (just checked in RAVE). But I still think that the problem comes from "the front end" ie - the pump. If one of the control valves in the block was leaking, the corresponding brake caliber would be pushed, wouldn´t it? I mean, the pressure cant just disappear into "nothing"? We are talking about a fluid @ 160 bar. As the original workshop manual says, you would see the leak (dripping). So when pressure is lost, the only way it can go without braking or dripping, is back through the pump - or am I totally wrong about this? Quote Link to comment Share on other sites More sharing options...
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