Markheliops Posted July 28, 2011 Share Posted July 28, 2011 Hi Gents. My mate Hans has purchased a Drops and is having an issue with the air pressure to get the thing to pass a German TUV test. His e-mail below: The German MOT has a last subject to be cleared. They say, the pressure available is too little. After braking a few times intensly, the air gauges drop in the red zone. It does not load more then app 7 BAR into the tanks, which gives it to their opinion too little reserve.... My questions, can you put that in the forum please. What should be the pressure at the gauges be, before the compressor 'switches off'?? What should be the pressure that the compressor delivers (I can then find out if it is worn..)?? I am presuming the compressor pressure can be adjusted by some degree or is this normal with Drops? Any advice on this issue will be appreciated Many thanks. Markheliops Quote Link to comment Share on other sites More sharing options...
protruck Posted July 28, 2011 Share Posted July 28, 2011 Hi Mark. Low air warning light should come on at 71 to 78 psi or 498 -538 Kpa. Full air pressure should be 120psi or 827 Kpa Hope this helps. If you want to call me, for any questions you may have. send me an email and i will give you my number. Regards Clive Quote Link to comment Share on other sites More sharing options...
Markheliops Posted July 28, 2011 Author Share Posted July 28, 2011 Thanks Clive. I have forwarded your reply on to Hans and I shall call you at some point with questions. Regards Mark Quote Link to comment Share on other sites More sharing options...
protruck Posted July 28, 2011 Share Posted July 28, 2011 OK mate. No problem, if i can help in any way just call.:-D Clive Quote Link to comment Share on other sites More sharing options...
LoggyDriver Posted July 29, 2011 Share Posted July 29, 2011 DROPS are notorious for loosing pressure on braking. That's why there is a manouver brake on the floor, so that you can load/off load flatracks without loosing too much pressure. This is just how they are. Quote Link to comment Share on other sites More sharing options...
protruck Posted July 30, 2011 Share Posted July 30, 2011 DROPS are notorious for loosing pressure on braking. That's why there is a manouver brake on the floor, so that you can load/off load flatracks without loosing too much pressure. This is just how they are. I think from the original post, that the vehicle is not building air to it's max operating pressure (120psi). this is the reason why it is not reaching the braking requirements on the German MOT test. Clive Quote Link to comment Share on other sites More sharing options...
Tony B Posted July 30, 2011 Share Posted July 30, 2011 If they have been standing about the compressors have a nasty habit of filling with a gungy foam of oil and water. like yellow Sn*t.. Strip and clean and it all works agin. Quote Link to comment Share on other sites More sharing options...
Richard Farrant Posted July 30, 2011 Share Posted July 30, 2011 From my days of base overhauling Leyland DROPS during the Bosnia campaign as well as the SEME diagnosis and repair course prior, I have turned my mind back and would say the first thing to do is to check throughly for any air leaks, from pipes and valves. Once ascertained that this is correct then go through the system checking pressures at the test points to pinpoint the problem area. TonyB mentioned gunge in the compressor, in reality this should be dealt with by the Air Dryer, it might be wise to change the cartridge if it does not look if it has been replaced for a while. Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted July 31, 2011 Share Posted July 31, 2011 If capacity is an issue, it should not be difficult to obtain an off the shelf reservoir, brackets, pipes and fittings to add extra air capacity. I think most of the plumbing should be plastic pipes on a vehicle that age. Quote Link to comment Share on other sites More sharing options...
Markheliops Posted August 2, 2011 Author Share Posted August 2, 2011 Thanks for your advice everyone. Hans has taken note and I shall report back with any updates. Regards Mark Quote Link to comment Share on other sites More sharing options...
protruck Posted August 2, 2011 Share Posted August 2, 2011 (edited) Hi Mark. If Hans needs an air system drawing give me a shout and i'll scan them in and send them to you. Clive Edited August 2, 2011 by protruck Quote Link to comment Share on other sites More sharing options...
Markheliops Posted August 3, 2011 Author Share Posted August 3, 2011 Update from Hans. On the system there is an airdryer from WABCO. In that unit there is a 'imbus' screw that regulates the airpressure blow off point. Simply turn it, and the air is released at an erlier, or later stage thus incresing the airpressure in the system. We have now regulated it on roughly 8,5 BARS which should be enough for the German MOT. We are back for a last check tomorrow!! Keeping my fingers crossed. Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted August 5, 2011 Share Posted August 5, 2011 That equates to 120 psi so should be fine. Out of interest, what was it unloading at before? Quote Link to comment Share on other sites More sharing options...
Markheliops Posted August 5, 2011 Author Share Posted August 5, 2011 That equates to 120 psi so should be fine. Out of interest, what was it unloading at before? After braking a few times intensly, the air gauges drop in the red zone. It does not load more then app 7 BAR into the tanks, which gives it to their opinion too little reserve.... Hans description of the fault mate. Quote Link to comment Share on other sites More sharing options...
Grasshopper Posted August 5, 2011 Share Posted August 5, 2011 7 bar sounds too low (98 psi). Most commercials run at 120 psi. Quote Link to comment Share on other sites More sharing options...
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