cruiseliner64 Posted 22 hours ago Share Posted 22 hours ago Hi all,We started the Cruiseliner for the first time in 7 months today and it started first turn of the key....but it wont build air pressure over 20psi.When the engine is shut down the air can be heard leaking back through the compressor.Im thinking its the unloader valves are stuck.My question is does the compressor head have to be taken off to clean them or is there some other way to clean them? I think its a Midland compressor.Thanks Paul Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/ Share on other sites More sharing options...
Joey Mack Posted 21 hours ago Share Posted 21 hours ago (edited) Is the D-2 governor new ? If not, they are cheap enough to just replace it. You can try to spray a very light oil into the intake of the compressor and gently tapping on the head with it running while doing this. 7 months idle may have them stuck. Edited 21 hours ago by Joey Mack More info needed 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587007 Share on other sites More sharing options...
Geoff Weeks Posted 21 hours ago Share Posted 21 hours ago If it is leaking back through the compresssor, it is the outlet (exh) valves. If the gov is mal functioning it can leak through the unloader. Try disconnecting the gov from the unloader and see if it will build. Caution: with gov disconnected it will never stop building air pressure, so don't run it all the way up. If it builds to over 60, shut it down and you know the gov is the problem. 2 Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587010 Share on other sites More sharing options...
cruiseliner64 Posted 2 hours ago Author Share Posted 2 hours ago Thanks for the replies.I disconnected the govenor but it still behaved the same.I tried a little light oil in the intake tapping with a hammer but again I had no joy.I think the head has to come off to sort this.The problem with taking the head off is the chances of getting a gasket over here is zero.Could the gasket be reused for a short time untill I can get a new one or could I cut one from heavy gasket material?.I thought it was a Midland compressor but not sure now.Heres a few pics of it see if you guys know what it is...Thanks again for all the help. Paul 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587048 Share on other sites More sharing options...
Geoff Weeks Posted 2 hours ago Share Posted 2 hours ago Bendix Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587049 Share on other sites More sharing options...
Geoff Weeks Posted 2 hours ago Share Posted 2 hours ago Did you take the air gov off? (thing bolted to the left side of the compressor) and try it? I see way more gov problems then I do compressor problems. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587050 Share on other sites More sharing options...
Geoff Weeks Posted 2 hours ago Share Posted 2 hours ago What little I can make out it is a TF-501 Bendix. One of the most common for its day. Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587051 Share on other sites More sharing options...
cruiseliner64 Posted 1 hour ago Author Share Posted 1 hour ago Yes I took the govenor off and it was still leaking back through the compressor.I know the pic isnt great but its the best shot I could get as its buried low in the frame.Im thinking its the unloader valves thats stuck.Many thanks for your replies. Paul Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587053 Share on other sites More sharing options...
Geoff Weeks Posted 1 hour ago Share Posted 1 hour ago If the unloader is stuck, it holds the intake valves open, not the exhaust, so it would not leak back from the tanks when the truck is turned off. It does sound like the exhaust valves are leaking . I would likely remove the outlet fitting and run the truck a max rpm and try and "blow out" any debris that might be keeping the valves from closing. Doing this will pass the max amount of air through the valves. Anything else will require pulling the compressor and/or head. 1 Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587055 Share on other sites More sharing options...
cruiseliner64 Posted 49 minutes ago Author Share Posted 49 minutes ago Thanks Geoff,I will try that tomorrow.If it doesent work Ill remove the head and see whats going on.I will let you know.... Paul Quote Link to comment https://www.bigmacktrucks.com/topic/76229-low-air-pressure/#findComment-587066 Share on other sites More sharing options...
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