Air Pack Bad??/Time for rebuild?

[weld88]

Ok guys so crawled under the truck and let it run for about 10 min. Air pressure only got to 80 lbs. I believe my hunch was right (the air pack). Basically when I turn the truck off I sprayed the entire air pack and all lines, I did not see any physical evidence of an air leak BUT there has been a constant hissing coming from the blow by tube that goes down by the turbo, I noticed that I large air line runs into this vent tube and that is where the hiss is coming from. I traced this line back to the air pack.

Also I noticed once I apply the brakes that hiss stops and once I let off it comes back.

What do you guys think? Obvious air pack rebuild? If so where is a good place to get a rebuild kit?

Thanks for the input welldigger aboit the hissing sound that basically described the symptom to a tee.

 

[welldigger]

I have a brand new rebuild kit for that short air pak ill sell cheaper than the parts dealers. P.m. me if your interested.

 

[weld88]

I am interested. Sent PM

 

[fasttruck]

REMEMBER THERE ARE CHECK VALVES THAT ARE SUPPOSED TO KEEP THE AIR FROM LEAKING BACK THROUGH THE COMPRESSOR. nO LEAKS AT THE AIR HORN ? wINDSHIELD WIPER CONTROL VALVE NOT LEAKING ? ACCESORY AIR PETCOCK ON PASSENGER'S SIDE OF FIREWALL CLOSED (THIS IS WHERE YOU HOOKED UP THE ORIGINAL BILI AIR HOSE FOR THE TIRES) ? ON A STRAIGHT TRUCK YOU ARE ALLOWED 2PSI/MIN LEAKAGE WITH THE BRAKE RELEASED AND 3PSI/MIN WITH THE BRAKE APPLIED. THIS USUALLY CREATES AN AUDIBLE AIR LEAK.

 

[gimpyrobb]

No need to yell, Capt. Caps Lock!

 

[JH1]

Remember that there is a lubrication port on the back of the pack. Most people have never heard of it. It's an allen head set screw. Unscrew it and squirt some 10wt air tool oil in there. The real trick is removing the set screw without stripping the hex socket, since they may not have been removed for 40 years. I had a 5T airpack that was gummed up from no lube. The big and also the small pistons have to have some lube on them if they are expected to freely travel back and forth in their appointed tasks.

 

[gimpyrobb]

Remember that there is a lubrication port on the back of the pack. Most people have never heard of it. It's an allen head set screw. Unscrew it and squirt some 10wt air tool oil in there. The real trick is removing the set screw without stripping the hex socket, since they may not have been removed for 40 years.

Not on the shorty air packs, just the long ones.

 

[welldigger]

Not on the shorty air packs, just the long ones.

Ditto. I don't believe the short ones were meant to be lubed.

 

[ATPTac]

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

I wasn't aware it had one... Thanks for the input. I'll look up how to do that and see if that takes care of it.

 

[JH1]

Interesting. I didn't know there were some that weren't meant to be lubed. Sounds like a bad idea to not have lube in there. Maybe that's why subsequent ones have lube ports?

 

[gimpyrobb]

The short ones are the newer style.

 

[silverstate55]

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??

If the upper seal inside the air slave housing is bad, it will let air bypass out of the vent in the engine compartment (next to the air cleaner)...find which one is venting air pressure and trace it back to its source to find the problem.

 

[weld88]

So... got another question for you guys. After I rebuild my Air Pack and get it back on what is the procedure for bleeding the brakes? I have done a little research and found out how to "power bleed" brakes but is there more just a conventional way to do it? Would you bleed them like a normal truck, just pump the brakes and the turn the bleeder valve on the air pack?

Thanks

 

[ATPTac]

Yeah, its a 2 person job. One pumps the other bleeds, start with the wheel furthest from the master cylinder. Also make sure you spend a decent amount of time on that cylinder to work out most of the air.

 

[weld88]

Ok thanks, what would you bleed first? This air pack or the brakes? I would assume the air pack so you get get all the air out right there but I may be wrong.

 

[clinto]

Ok thanks, what would you bleed first? This air pack or the brakes? I would assume the air pack so you get get all the air out right there but I may be wrong.

Airpack first, then start at the wheel cylinder furthest away and work your way towards the airpack (right rear, left rear, right middle, left middle, right front, left front).

Build a bleeder-it's so fast it's absurd. You'll never do it the old way again, I promise.

 

[weld88]

So I assume the way a power bleeder works is you just pressurize the system and then bleed the air pack, then pressurize again and do each wheel? Correct?

 

[Merc1973]

To bleed, i plan on buying a remote brake master cylinder reservoir kit from the classifieds on SS:

http://www.steelsoldiers.com/showth...series-5-ton-Remote-Brake-Fluid-Reservoir-Kit

and then this pressure bleeder to attach to the remote reservoir.

http://www.speedwaymotors.com/Motiv...ake-Bleeder-Wilwood-Master-Cylinder,5790.html

 

[DeucesWild11]

I would double check all the airlines, if you can hear it you should be able to see it with the soapy water, or windex.. I had a hissing sound coming from the front end last week and found my main line coming off the air pump had rubbed against the frame and caused a hole in the line. A quick trip to Home Depot for a new copper line did the trick.. Amazing the thickness difference in the tubing these days..

 

[welldigger]

To bleed, i plan on buying a remote brake master cylinder reservoir kit from the classifieds on SS:

http://www.steelsoldiers.com/showth...series-5-ton-Remote-Brake-Fluid-Reservoir-Kit

and then this pressure bleeder to attach to the remote reservoir.

http://www.speedwaymotors.com/Motiv...ake-Bleeder-Wilwood-Master-Cylinder,5790.html

I just put a tee and a valve in the remote reservoir line. Now my homade power bleeder works with stock deuces and mine. And I only have about $25 in my homade unit.