69R700

Thanks everyone for there help. The Wagner moisture ejector was the culprit tryed to get another one but they are no longer availble so had to bypass it and that solved the problem. Bob

Hi replaced the relay valve last night and still have air coming out of the foot valve ,I also took apart the moisture separator Wagner It has 2 lines connected to it one comes off a t and the other connects right to it ,then there is elbow plugged so how does it expell moisture ? inside valve there was no spring under that nut on top just a diaphram . Iam going to check the trolley valve, mechanic said a lot of people overlook it I HOPE . Bob

Hi Thad when I build up air pressure and throw the tractor protection valve from normal to emergency air pours out of the red trailer line when the tractor brakes are in the released position. Bob

Hi Thad capped off the rear brake chambers last night and still the same problem but I think I found the problem the valve behind the cab on the drivers side mounted in between the frame rails to cross member has 4 air lines going to it and every time I step on the brake air is pouring out the top of valve near the fittings all cooper. I going to replace the valve this week and take some pictures of some of the other valves on the truck which I think one of them is a moisture separator. Tractor also has front brakes . Hope some of these valves are still availble ,there all orignal. Thanks Bob

Hi Thad yes I have spring type brakes ,the truck has a red dash valve for air reserve which is in the pulled out position,in between the seats is the wet and dry pavement selector ,the tractor brakes,and the tractor protection valve normal/emergency which is in the normal position.Thad if I release the parking brake and throw the tractor protection valve to emergency shouldnt i get air coming out the red air line to the trailer?

Hi, Thad - Yes, the brakes do feel like they're dragging a little bit. I don't have an air dryer but do have a filter off the compressor. It's a Detroit diesel 8v71 so it's a little different from the Mack system. I'm planning on selling the truck and now this problem popped up ... I'm really not familiar with this so I haven't been able to repair it. Any information is appreciated. In the meantime, I'll just keep plugging along. Thanks. - Bob P.S. Thad ... I think you're from Queens??? I'm on Long Island. Do you do any repair work on the side?

Hello, I have a 69 R Model Mack. 2-3 weeks ago I took the truck for a ride, hit a couple of nice sized pot holes and by the time I got back to the yard I was losing air pressure (getting up to about 50 PSI of air). If I rev the engine, I can get up to a little over 60 PSI. I found air was coming out of the bottom of the foot valve while the truck was shut off. Today I put in a brand new foot valve and still losing air out of the bottom of the foot valve. Somebody told me to look at the valve behind the cab ... it has 3 copper lines feeding into the bottom and the 2 trailer air lines come out of the top. Can anyone recommend anything else I can look for? Thanks. - Bob

Hi, Fullfuel - I haven't really taken the truck for a long drive, maybe 20-30 miles -- with those 44K rears it's a little rough. I put all new rubber cab mounts, let some air out of the tires -- it helped a little bit but not much. - Bob

Here are some pictures of my - Bob

Here are some pictures of my - Bob

Hi, B61Bill - I have a '69 R773ST with an 8V71, 13 speed Road Ranger. 44K camelback, 4.50 ratio, Kysor roof mount a/c, all original from the factory. It was used in the Long Island area to haul a sandbox. Here's a picture of the truck - restoration is in progress. The truck is real fun to drive if you have a kidney belt on (real short wheel base and it sounds great. - Bob