Air Pressure build slowly

Topic: Air Pressure build slowly (Read 2436 times) previous topic - next topic

Re: Air Pressure build slowly

Reply #25 – May 27, 2020, 09:38:12 pm

Hi Brett,
I replaced The old Air Dryer with a napa reman da33100x. I don't think it made any difference. What governor?

Pat,

Re: Air Pressure build slowly

Reply #26 – May 27, 2020, 09:42:33 pm

Pat,
The governor is what controls cut-in/cut-out PSI for the air compressor. Easy to replace and under $25 at any parts house that deals with OTR trucks: air compressor governor - Penelusuran Google

Re: Air Pressure build slowly

Reply #27 – May 27, 2020, 10:44:39 pm

Quote from: pthurman48 – May 27, 2020, 09:38:12 pm

What governor?

Haldex D2 Governor Service Data

Re: Air Pressure build slowly

Reply #28 – May 27, 2020, 11:05:13 pm

If you put a new governor on and the pressure is not enough, take the cap off, loosen the nut and turn the screw CCW to raise the pressure part of a turn at a time until you are happy. Mark the governor with a black felt so marker you remember which way increases/decreases.

Pierce

Re: Air Pressure build slowly

Reply #29 – May 28, 2020, 08:37:36 am

I am clueless where the d2 governor is on my U-240 Cat 3116. I have never seen this thing!

Re: Air Pressure build slowly

Reply #30 – May 28, 2020, 09:17:54 am

bolted to your air compressor with two 1/4" bolts.

Re: Air Pressure build slowly

Reply #31 – May 28, 2020, 09:19:17 am

Quote from: pthurman48 – May 28, 2020, 08:37:36 am

I am clueless where the d2 governor is on my U-240 Cat 3116. I have never seen this thing!

The short answer is "On top of the air compressor."

The more compassionate answer is:

Looking in the engine compartment is confusing at first so break it down into things you know.
Find the Starter, the alternator, the water pump and the hydraulic pump for the power steering.
The fuel injection pump has as many steel pipes running from it as cylinders in the engine. Plus a couple more for fuel in and out. And a cable somehow connected to the foot feed. And a wire.
The air compressor is usually gear driven by the engine and looks like a two cylinder compressor with a black coolie hat. The thing wearing the coolie hat bolted to the compressor is the D-2 governor. In operation it lifts the valves in the compressor to stop the pumping action. The D-2 is the most common failure. Second is the mechanism that lifts the valves out of operation. Air dryers should be replaced on a calendar basis and never fail. Failure can be expensive. D-2 governors are inexpensive and a spare is cheap insurance.

I'll be back to normal soon.

Re: Air Pressure build slowly

Reply #32 – May 28, 2020, 09:30:58 am

Where do we buy a d2 governor? Part number?

Re: Air Pressure build slowly

Reply #33 – May 28, 2020, 09:37:45 am

Napa

Governors - Air Brake Compressor - H/D Truck D2 Bendix Haldex MBI 275491RX |...

Re: Air Pressure build slowly

Reply #34 – May 28, 2020, 10:03:44 am

Good Morning All,
Thanks for those quick replies, I found the governor. Never saw one before,

On my way to parts store.
Just some pics. The air gauge shows whats left of the 90psi air pressure from about 4:00pm yesterday until just now 8:55am about 45psi. The other pic is the D2 governor on my 94 Cat 3116.

Re: Air Pressure build slowly

Reply #35 – May 28, 2020, 10:22:03 am

Quote from: pthurman48 – May 28, 2020, 10:03:44 am

Good Morning All,
Thanks for those quick replies, I found the governor. Never saw one before,

It's a learning curve to be certain, but for me it's easier than trying to learn how to use my new telephone now that Tracfone has deprecated our Blackberry-like Motorola phones with the QWERTY keyboard.

Today I set up voice mail.

For our new home I started with "How do I check the oil level?" Moved on to "We're going to need a bigger pan." Through "What the hell are Wedge Brakes?" to "Oh. That's a quick dump valve, I know how those work."

Small bites. It was foolish to think I could master the new telephone technology in one sitting. Analysis determined that a land line with a rotary dial phone wasn't feasible

Re: Air Pressure build slowly

Reply #36 – May 28, 2020, 06:32:04 pm

I got the d2 Governor replaced, it was not easy. The two bolts on each side of the air hose connection that is on the side of the governor, must be tightened leaving the flats facing the air connection fitting. The air connection fitting will not install/turn because it's point hits the mounting bolts. After standing on my head half the time and the other under the engine it is installed.
NO HELP/CHANGE!

I tried patting the gas peddle and the white needle reacts to it and falls a lot, red will not fall, this was going 55MPH.

Had to adjust the new d2 governor, it was set at 130psi, I lowered to 115psi.

Re: Air Pressure build slowly

Reply #37 – May 28, 2020, 06:49:40 pm

130 is good 115 isn't most run from 90 to 120. Back to my reply #9 you only have an air leak when the engine is running and it will be either in the airline from the compressor to the dryer or the dryer itself. If you can spray a dish soap solution on everything from the compressor to the dryer exhaust while the engine is running you might find it.

Re: Air Pressure build slowly

Reply #38 – May 28, 2020, 07:31:06 pm

Quote from: craneman – May 28, 2020, 06:49:40 pm

130 is good 115 isn't most run from 90 to 120. Back to my reply #9 you only have an air leak when the engine is running and it will be either in the airline from the compressor to the dryer or the dryer itself. If you can spray a dish soap solution on everything from the compressor to the dryer exhaust while the engine is running you might find it.

NAPA truck shops can make those flexible air lines. After 20 years it wouldn't be extravagant of you to replace them all.

Re: Air Pressure build slowly

Reply #39 – June 05, 2020, 10:12:36 am

This morning I got under the MH and sprayed soap water on anything that looked like air. This includes both air tanks(all connections), things with several air connections(both at the rear and front), connections to the air dryer, connections on the air compressor, all connections and things on the cruise control board, checked the value on the aux air hose in fuel bay. Looks like a lot of my air lines are hard black plastic. Hoses to air cambers of the brakes at the wheel. Over night(15hrs) it lost from 70psi down to 25psi . The air pressure build up is still very slow. At 2000RPM it will make it to 115psi. I can hear the dryer blow off.

Pat,

Re: Air Pressure build slowly

Reply #40 – June 05, 2020, 02:30:29 pm

Had a similar problem last year, especially in higher altitude areas with colder weather. Took forever to get enough air pressure built up. Took coach to MOT and they diagnosed the problem as the rear ride height control valve. Here is an article on the valve. ride-height-adjustment-in-motorhome-or-rv

Hope this helps!
Greg

Re: Air Pressure build slowly

Reply #41 – June 05, 2020, 06:28:41 pm

Hi Greg,
My U240 does not have air bags. I have air brakes, throttle, cruise control. and aux air hose. That is all there is to my air system.

Pat,

Re: Air Pressure build slowly

Reply #42 – June 05, 2020, 09:31:18 pm

Quote from: pthurman48 – June 05, 2020, 10:12:36 am

Over night(15hrs) it lost from 70psi down to 25psi . The air pressure build up is still very slow. At 2000RPM it will make it to 115psi. I can hear the dryer blow off.

Pat,

Pat, the air dryer blow off is switched by the D2 governor. I think you need to find the line taking compressed air from the air compressor to the dryer and the line from the dryer to the wet tank. Check them for leaks.

Re: Air Pressure build slowly

Reply #43 – August 12, 2020, 01:41:05 pm

Update:

Today I got the Cat rebuilt air compressor installed. The air pressure problem is solved, it was the compressor.

$900 labor and $650 parts.

Pat,

Re: Air Pressure build slowly

Reply #44 – August 12, 2020, 07:04:58 pm

I dont think that the compressor should have system pressure on it ,sitting. Should be a check valve. You may still have something faulty. I hope not .

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