<SPAN style="COLOR: #ffffcc">[3]There are a couple posts running on this topic right now!<SPAN style="mso-spacerun: yes"> I’ve had the exact problem you describe.<SPAN style="mso-spacerun: yes"> I found that the metering valve that sends the proportioned air to the back of the air can was hanging up and letting a small amount to the piston.<SPAN style="mso-spacerun: yes"> You can find out real quick by disconnecting the air line feeding the back of the can.<SPAN style="mso-spacerun: yes"> Air will be flowing when you’re not on the brake pedal.<SPAN style="mso-spacerun: yes"> It does not take much air to cause big trouble.<SPAN style="mso-spacerun: yes"> My take on the situation is this: The problem seems to start out slow, but as the brakes start to drag a little, the effect seems to become exponential.<SPAN style="mso-spacerun: yes"> The brakes begin to drag ever so little, but as you start to generate some heat the silicone fluid “grows” very quickly, (I've read it has a greater expasion rate than Dot3),and eventually will lock the brakes up or at least have them dragging hard. It all depends on how much air the metering valve is letting by.<SPAN style="mso-spacerun: yes"> <SPAN style="mso-spacerun: yes"> I’ve had go as far as disconnecting the air line to the rear of the PAC, and bleed a little fluid off the system (because it has swelled with heat), out on the road just to limp home with a very heavy brake foot.<SPAN style="mso-spacerun: yes"> I flushed lots of AeroKroil through the inlet ports on the air side, flushing quite a bit of rust flakes out of the metered air line and exhaust port .<SPAN style="mso-spacerun: yes"> I’ve blown the reservoir tanks down hard and lots of rust came out.<SPAN style="mso-spacerun: yes"> I think they are the ultimate source of my problem.<SPAN style="mso-spacerun: yes"> I haven’t had a problem for a while, but am looking into piping in a filter/moisture trap off the discharge of the tanks just for piece of mind.<SPAN style="mso-spacerun: yes"> I may also go as far as to make new stainless tanks (when the materials become available at work) and put a pressure gauge on the metered air line, (run into the cab) so I can monitor what is going on.<SPAN style="mso-spacerun: yes"> <SPAN style="mso-spacerun: yes"> I'll be interested to hear what you find! Good Luck: Dave<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com
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