I have a 2007 Thomas with a Cat. I am currently having a air pressure problem. The bus builds air pressure to the 125 PSI cutout pressure of the governor and air dumps out the dryer. It will only build to 125 one time. Then any use of air down to around 0 it will not resupply the air to the supply reservoir. I have replaced the governor with 3 different ones and rebuilt the air dryer 3 different times. With the same result. I have even replaced the compressor. I fully understand the cutin and cutout of the governor and the supply functions. I do not understand why it only builds 1 time and will not again until the air pressure reaches a minimal amount? Any help would be above amazing. Thank you in advance.
i had the same problem with a motor home on a freightliner chassis. would build pressure one time. compressor would not re start. my dump valve would stick. pushed the valve manually back up in the bore and it would pump air again. i had some success spraying the valve from the bottom with wd 40 . has been working.
mark g, Thank you for replying. I have rebuilt the Air dryer 3 different times with 3 new dump vales and cartridges. With the same result every time. I will however take a known working AD9 off of a bus and install and see what the outcome is.
Great news. Exchanged the governor with a BENDIX governor and not a knock off from the local part store. Which allowed the air bags to indicate a bad leak. Changed the air bags and governor and walaaa back to normal operating. =)
2007 Thomas C2 on Freightliner Chassis
Posted - 07/07/2020 : 2:26:48 PM
