Air Pack Bad??/Time for rebuild?

[weld88]

So, picked up my first deuce and absolutely loving it. Truck runs great and drives great but im thinking i may have a bad aor pack (not real sure).. I am new to the deuce world but I do know I have the short style air pack ILO the long. I was wondering though exactly how you know if your air pack is going bad?? The reason I suspect mine is cause recently my air pressure is dropping quickly after shut off and sounds like I have a leak around my pack, does this mean my air pack is probably going bad if it's leaking air?

Any input or help with this is greatly appreciated!

Thanks

 

[rosco]

Air Pack or not, you have to find the leak. There is a standard DOT test, that says that your air should not leak off for a certain time. If you have full air pressure, and you shut off the truck, how long does it take, before the buzzer comes on, at 60 PSI? Same thing, full air, shut it off with the brakes full on (foot on the brakes), how long does it take for the air to bleed down to 60 PSI and the buzzer comes on?

 

[weld88]

With the truck running and no brakes applied I can only build 90 psi once shut down without applying brakes it only takes about 2 min to bleed down. The leak sounds internal to the air pack. Where are common leak areas or problem areas I should look for as well?

 

[Adrian A]

Rebuild the air pack. Install a repair kit and hone it out. A small flap wheel and an engine cylinder hone will be the only special tools. I feel this should be done as initial maintenance on a recent purchase. This is not something you want to be unsure of.

 

[welldigger]

Have you driven the truck? Does it stop well or do you have a good firm pedal but it doesn't stop worth a crap? There are several air lines near the air pak that can leak. We need more details before we just start assuming a $500 part is the problem.

For example, at the rear of the truck, are your glad hand valves shut and covers on?

 

[clinto]

Go put some soapy water in a squirt bottle and let air pressure build up. Shut the engine off, make sure the truck is chocked and in gear, parking brake applied and crawl under it with a flashlight, spray the soapy solution on all the air lines, the airpack, etc. and find the leak.

 

[weld88]

When my air pressure was up at 120 psi I had a good form pedal and stopped well, since my pressure now only Holds around 90 as of today pedal seems spongie and does not stop as well. I did check my glad hands did not hear our feel any leaks. I got under the truck and felt all around the lines close to the air pack and did not feel nothing but I may need to go back over the air lines all in that area. This basically all just escalated today.

One other thing is one I shut the engine down it sounds like there is a huge air leak inside the engine but more than likely this is just compression bleeding off. Thats a real neub thing to say I know but there isn't any reason or way air runs into the engine right??

 

[gimpyrobb]

Check your air governor.

 

[weld88]

Good idea clinto! Surprised I didn't think of doing that. I will tomorrow crawl under the truck and spray soapy water all over the air pack and nearby lines.

Welldigger I will double check my glad hands and make sure I don't have a leak back there. Any other place I should check I am looking over?

 

[gimpyrobb]

Check your air governor.

This.

 

[welldigger]

Next question. When you push the brake pedal does it continously vent air? Or only after you release the pedal.

And Gimp, if I had to guess I'd say the air he is hearing is coming from the vent tube by the airbox and firewall. Though, it doesn't hurt to check the air governor either.

 

[weld88]

Thanks gimpyrobb. This is right on the firewall correct? I will spray this with soapy water as well. If your air governer is bad you can pick this party up at napa I believe?

 

[weld88]

Welldigger, should I push the pedal while the truck is off, or while running. and when you say vent air where should it be venting from? The tube next to the air box?

 

[welldigger]

Running or not running you should be able to hear the "hiss". Though with the engine off it will be easier to hear. Your air pak should only vent air after you depress the brake pedal and release it. If you depress the pedal and hold it you shouldn't hear anything. If you hear air venting while holding the brake pedal down then there is a good chance the air pak is malfunctioning. The vent tube near the firewall is where the air pak exhausts the air. Which coincidentally the vent tube is near the air governor.

 

[welldigger]

Don't forget to check for leaks still. Use Clinto's idea and soak everything down with soapy water.

 

[weld88]

Ok I will definatley try that and see if I can hear the hiss. Thank you for the great input!!

 

[ATPTac]

Glad I saw this thread, my truck only builds pressure to around 90psi. I've seen some people say that's normal while others say 120psi is the normal level. Which is it? I don't have any audible leaks (haven't sprayed all the air lines).

 

[weld88]

ATPTac, I have not yet sprayed my lines to see where my air leak is coming from but I can just tell you how my truck is. Before this past weekend my truck would hold 120 PSI no problem while driving and then would also retain 120 PSI when shut off and slowly leak down over the corse of the day. Recently my truck only holds 90 PSI and leaks down very quickly within about 5 min, that tells me mine is not normal and caused from an air leak somewhere, also from what I have read and heard you want the 120 PSI mark but your truck should operate fine at 90 psi.

Next question, does your truck leak air down rapidly or hold the 90 psi and slowly leak down?

 

[welldigger]

He may just need to adjust his air governor up. I had to do that to mine.

 

[weld88]

Good call, being new to the deuce world myself I was unaware you can adjust your air governor. Thanks for that info good to know.