Had some problems with my tractor today :(

[JohnnyBM931A2]

Drove it to work this morning, as I have done since Monday. Everything functioned as it should (except for the lame stock heater.) It was 20 degrees when I left for work this morning, and it was only 28 degrees when I came back to the shop after I completed my job for the day. Parked my work van, and went into my truck to start warming it up. That is where I noticed the first problem: Flipped the battery switch, and set the truck to the run position. Nothing. No low air buzzer, no CTIS light, etc. Just for the heck of it I flipped it up more to try and start it... Nothing. Not even a single click or any kind of sound. Turned the switches back off (in the correct order, as I always do) then turned them back on.. Still nothing. Did it again, and everything worked on the truck as it should.. All the "sounds" were correct, and the CTIS light came on. Flipped the switch to start it and it fired up right away. Can anyone tell me what happened there?

And now for the second problem.. When I fired up the truck and it started to build up air pressure, I started to hear the depressing hiss of an air leak somewhere Walked around and couldn't pinpoint it. Since the gauges showed good air pressure, I decided to just drive it the 2 or 3 miles back home. The hissing continued the same way throughout the drive.. Did not get any louder, and pressure was good. In fact, pressure was TOO good... At first it went up to 135psi.. Then after a few minutes it went up to 145psi... Then after a few more minutes, as I came closer to my house, it hit 150psi (probably more than 150 though, since that is where the gauge stops. I should point out that I made several brake pedal applications in between each of these intervals. Seemed to creep up more after stop.

When I got home, I backed up into the driveway and let it idle for a few minutes. During that time, the pressure never went over 125-130psi. After I shut the truck off, I started to crawl around on the freezing driveway trying to find the leak. Without the noise of the engine in the background, I was able to find it quickly. It was a component coming off of the front of the air tank located next to the transfer case (I believe that is the wet tank?) There is a plastic screw on cap that covers the bottom of that piece, and that is what was leaking. I tightened it by hand, and the leak stopped. That cap on there seems very flimsy though... Can anyone tell me what this component is, and whether or not that would cause the overpressure issue? It's a black plastic or metal valve (or maybe a sensor) mounted to a brass 4-way air connection that is mounted to the front of the air tank. After searching through the -24P TM's I found something that looks close.. It is part 19 on Section II, Figure 264 Sheet 1. It says part 19 is Valve, Safety Relief. Part number 11669104. Now the way that the lines, etc. are setup is different from the TM. In the TM is shows a 3-way brass fitting, not a 4-way, and other things are different. On my truck, this "valve" has a threaded opening on the side that meets up with the front part of the brass 4-way fitting attached to the tank. Then there is an additional air line coming off of the top of this valve. Then on the bottom there is a flimsy plastic cap or something that threads on.

Can anyone give me more info about this valve, and whether or not it would cause my overpressure issue because it was leaking? I am really hoping this part is the cause of that.

Thank you in advance for any help! I'm not going to drive the truck again until I get this resolved

Edit: Just went out and checked it again, since it has been a few hours since I parked it. No hissing of any kind, and the pressure on both gauges has only dropped about 5 psi.

 

[JohnnyBM931A2]

Well.. I'm an idiot. After searching using different terms, I found the valve in question. PPV.
And a link brought me to one that looks exactly the same as mine>
http://www.vanhorntruckparts.com/product/20777/PR-2-Pressure-Protection-Valve/

It seems that this problem is not too uncommon.. Other people mentioned the overpressure issue. Can anyone tells me why that would happen? I thought the PPV's purpose was to stay closed until you hit 60psi, then once it opens you can use the wipers, etc. How does a failure of the PPV cause this pressure issue?

 

[Scar59]

The short commute (2-3 miles) is not healthy for that truck, especially in winter. The truck never gets to a sustained operating temperature and it will build moisture in the engine and air system. Your ppv was most likely froze up. Also the batteries do not recover with short/cold drives. Your electric issue is a relay sticking in the PCB, a possible symptom of weakened batteries. You may want to rethink your choice of commuter vehicle.

 

[Coffey1]

These trucks love to be run even run hard.
When they sit they seem to have more problems.
All the valves will get crusty check valves ppv due to moisture and gunk.
Just like the tire Davit pole that never gets pulled out and that one time you need it you can't get it to move. All these items need to be checked at least every 6 months. Tire pole once a month.

 

[JohnnyBM931A2]

I see. As far as the batteries are concerned, they are the original military batteries. I have not tested them, but they have been working fine. Maybe they should to be replaced.

 

[Coffey1]

No just load test them you could have a bad one or two in the mix.
I would not change them until they have failed unless you got cash to burn.

 

[Scar59]

You're fortunate that the original batteries are starting the truck. Short drives will tax them. Individually charge them, then load test them individually. You may find a weak one. If not, drive on. Not just 2 miles at a time.

 

[lindsey97]

Drain your air tanks. Make sure the air dryer is working correctly. The ambient temps combined with wind chill effect while driving will freeze air tanks and circuit valves fast. I have experienced loss of brakes in a dump truck due to freezing moisture in a relay valve. I removed my ppv on my personal truck. Simplifies things, and I won't be stuck on the side of the road due to a part being frozen.

 

[JohnnyBM931A2]

Drain your air tanks. Make sure the air dryer is working correctly. The ambient temps combined with wind chill effect while driving will freeze air tanks and circuit valves fast. I have experienced loss of brakes in a dump truck due to freezing moisture in a relay valve. I removed my ppv on my personal truck. Simplifies things, and I won't be stuck on the side of the road due to a part being frozen.

Yup. I drain them after every use. Usually only get moist air coming out... Never any liquid water. Air dryer blasts out a decent amount of water when I am around see it. That's an interesting idea about removing the PPV valve. However, wouldn't that make the CTIS system go into action sooner? Or is it activated by time delay in the module, rather than waiting for proper air pressure before it starts working? I ask because I can't have the truck honking at 5:30 or 6:00 in the morning when I leave for work. The neighbors have been very reasonable when it comes to me having this truck in the driveway, etc., so I don't want to be waking them up in the morning. If it wasn't for that, I could let the truck run for quite a while in the morning before I start driving.

I'm pretty pissed about how ineffective my block heater is. Truck doesn't seem to start any better/warm up any faster on days where I do use it. Probably a stupid question, but would my truck heat up any faster if the fuel was turned up? Pretty sure I know the answer, but I figured I would ask.

 

[wheelspinner]

It seems that this problem is not too uncommon.. Other people mentioned the overpressure issue. Can anyone tells me why that would happen? I thought the PPV's purpose was to stay closed until you hit 60psi, then once it opens you can use the wipers, etc. How does a failure of the PPV cause this pressure issue?

The PPV is supposed to open at 60 PSI or so and begin feeding the rest of the secondary and accessory air systems. Its primary purpose is to ensure the primary brake system receives its air FIRST. The air governor, is part of the accessory air system. Until this system can get air, the governor will never see the air pressure. Because of this the governor will not tell the compressor to stop making air, as it thinks there is no air because it hasn't seen it yet. The safety valve will blow off at 150 psi, which it will easily see if the compressor is never unloaded.

 

[wheelspinner]

I'm pretty pissed about how ineffective my block heater is. Truck doesn't seem to start any better/warm up any faster on days where I do use it. Probably a stupid question, but would my truck heat up any faster if the fuel was turned up? Pretty sure I know the answer, but I figured I would ask.

What kind of block heater? Mine was great with about a 2 hour plug in. Would already be blowing warm air from the heater. This was with my first 5 ton with the 855 which is normally a COLD BLOODED BEAST. No ether. No anything. Just flipped the switch. Does the engine block feel warm to the touch? It should.

https://www.youtube.com/watch?v=Isr9dcywkwU

 

[JohnnyBM931A2]

The PPV is supposed to open at 60 PSI or so and begin feeding the rest of the secondary and accessory air systems. Its primary purpose is to ensure the primary brake system receives its air FIRST. The air governor, is part of the accessory air system. Until this system can get air, the governor will never see the air pressure. Because of this the governor will not tell the compressor to stop making air, as it thinks there is no air because it hasn't seen it yet. The safety valve will blow off at 150 psi, which it will easily see if the compressor is never unloaded.

Thank you! That makes sense now

 

[JohnnyBM931A2]

What kind of block heater? Mine was great with about a 2 hour plug in. Would already be blowing warm air from the heater. This was with my first 5 ton with the 855 which is normally a COLD BLOODED BEAST. No ether. No anything. Just flipped the switch. Does the engine block feel warm to the touch? It should.

https://www.youtube.com/watch?v=Isr9dcywkwU

It's a Kats 1000w freeze plug heater. After I installed it and used it for the first time, I did feel the engine block, and it was very warm. However, I have not tested it again since. I will do that after work today. Maybe it burned out already because it was faulty, or maybe the plug somehow came a little loose.

 

[Andyrv6av8r]

Yup. I drain them after every use. Usually only get moist air coming out... Never any liquid water. Air dryer blasts out a decent amount of water when I am around see it. That's an interesting idea about removing the PPV valve. However, wouldn't that make the CTIS system go into action sooner? Or is it activated by time delay in the module, rather than waiting for proper air pressure before it starts working? I ask because I can't have the truck honking at 5:30 or 6:00 in the morning when I leave for work. The neighbors have been very reasonable when it comes to me having this truck in the driveway, etc., so I don't want to be waking them up in the morning. If it wasn't for that, I could let the truck run for quite a while in the morning before I start driving.

I'm pretty pissed about how ineffective my block heater is. Truck doesn't seem to start any better/warm up any faster on days where I do use it. Probably a stupid question, but would my truck heat up any faster if the fuel was turned up? Pretty sure I know the answer, but I figured I would ask.

The CTIS is activated,if you will, by a pressure switch next to the PPV valve off of your wet tank. It's set to a higher pressure than the PPV.

 

[Trailboss]

When you flipped the battery switch, did any of the gauge needles move (usually fuel and battery needles will move)? If not, the issue is somewhere between or including the batteries and the battery switch. If the needles moved, but nothing happened when you turned start switch, the issue may be either the run switch, weak batteries or loose cables, or the transmission was not fully in neutral. I've had a couple of trucks that I had to jiggle the gear shift lever to make sure the neutral interlock switch was making contact.

 

[JohnnyBM931A2]

When you flipped the battery switch, did any of the gauge needles move (usually fuel and battery needles will move)? If not, the issue is somewhere between or including the batteries and the battery switch. If the needles moved, but nothing happened when you turned start switch, the issue may be either the run switch, weak batteries or loose cables, or the transmission was not fully in neutral. I've had a couple of trucks that I had to jiggle the gear shift lever to make sure the neutral interlock switch was making contact.

To be honest I can't remember. However, I did try jiggling the gear lever, because there was one time a while back when I had a no-start. Turned out that I had left the truck in reverse.

 

[JohnnyBM931A2]

So I tested my block heater today.. Block was warm to the touch, as it should be.
I had another thought.. Is it possible that I could have a thermostat issue? Do the thermostats on these trucks fail in the open position, or the closed position?

 

[Coffey1]

John my truck will not reach heater temp until I drive about a mile or two then it will run you out of truck.
1. Are the vents open
2. Is the blower working can you feel difference between high and low
3. Have you touched heater hoses to see if they are hot.
4. Are you sure valves coming off engine are totally open.

 

[Coffey1]

And my heat had no problem keeping me warm even when I had soft top.

 

[SWMARTINA]

block heater my M813 will actually melt the snow off the hood if left on over night. 4 hours has the block plenty warm. It a standardard bolt on cummins coolant heater that replaces the plate on the side of the engine block. Bill