mysterious air leak
2003 Discovery 39s. When driving the air pressure in the front tank cycles from 120psi to 95psi and back every 15 seconds. Sitting still with engine running air pressure is steady at 120psi. Rear ai...
Forum Discussion
There is not a front tank and a rear tank. You have a primary tank which is the wet tank and then one or two secondary tanks. The primary (wet) tank should collect any moisture before the air goes on to the other tanks. The primary tank you should be draining the moisture off. It also has a pop off safety valve (automatic air release) on that tank. If it pops off air pressure at less that 140 psi, it should be replaced. Sounds like your is popping off at 120 psi. But someone has to be under there to know for sure. there is a screw out plug on that tank where you can install a air gauge to monitor and see where it is doing. A diesel shop would have a pit to make it easier to get under there and see what is happening!!!
Meritor Troubleshooting Guide
Meritor Troubleshooting Guide
