deuce air leak

[salvorone@aol.com]

i am new to posting , i have a 70 deuce and she wont build air past 50 when i shut her down i can feel and hear air escaping fron the engine crankcase breather tube ?? matbe someone can help thanks salvorone ps she just started this thanks

 

[Heavysteven]

I would take a bottle of soapy water and find out where it is coming from.

Air escaping from the breather tube I can't explain.

 

[airmech3839]

Mine had a chaffe in the outlet side pipe at the frame and was not letting pressure build up at all. I did a temp fix and it gets up to and holds about 95psi now but bleeds out in about an hour or two. I would check that you are not just hearing air from another spot.. It is very noisy up there and even with the engine off... mass quantities of air from system can have a weird way of sounding like they are coming from other places.. as stated by Heavysteven... use a soapy water mixture and check for bubbles... At the rate you are talking it may be more like blowing.... let us know how this turns out... cause if it is from breather then there are other issues than just air compressor being bad...

 

[gringeltaube]

.... cause if it is from breather then there are other issues than just air compressor being bad...

I was going to say bad air compressor until I read this.......
What else do you think it could be? There are only two air lines running to- or from- the compressor. With eng. standing still the gov. control output (1/4" tube) should hold air inside, even at only 50psi. If both, gov. AND comp. are bad, some air could get into the engine's crankcase, but not a massive blow-by out of the breather tube.
Now, most Deuces I have worked on don't have that check valve in the main output line, at the entrance to the primary air tank so if the compressor head valves don't hold air it would blow past the comp. piston (s) & rings and down into the engine's crankcase through the oil return.

I've never had this particular (OP's) problem here, so I'm just guessing....

G.

 

[salvorone@aol.com]

thanks for the fast reply ive done more checking ,there is a copper line coming from the brake booster to the breather tube ,it also has two small lines attached to the copper line with fittings going to the fuel tank and the other goes to the master cyl cap , i think this must be a common vent tube on the side of my booster is a valve i think thats the problem trouble my manual shows a diffrent booster arrangement ?? what is your thought on this?? thanks

 

[salvorone@aol.com]

thanks for the fast reply ive done more checking ,there is a copper line coming from the brake booster to the breather tube ,it also has two small lines attached to the copper line with fittings going to the fuel tank and the other goes to the master cyl cap , i think this must be a common vent tube on the side of my booster is a valve i think thats the problem trouble my manual shows a diffrent booster arrangement ?? what is your thought on this?? thanks does anyone have an updated breakdown on the booster and valve?? i have bought this 1 1/2 years ago from g/l warner robbins and lots of parts were just replaced, thats why i think this might be a new er booster ,on the vacume can it has a long snout where thr end bolt goes that holds the bracket

 

[rlwm211]

It is not a vacuum can, it is operated by air controlled by the actuator of the air pack. The long boss on the back of the air pack indicates you have a newer style airpack as opposed to the old style.
I would suggest you see if the vent line is constantly allowing pressurized air to escape and if so you have a bad seal inside the air pack.
The other possibility is that the unloader is leaking and not allowing the system to come to full pressure. If you have shop air you can pressurize the truck and see where the leak is without running it which will make diagnostics a bit easier. if not, you will have to run the truck and build up air and look for the source.

RL

 

[salvorone@aol.com]

hey rl your dead on the money i took the valve apart anf it has a small aluminun disc with a snap on rubber cover on it ,the aluminum disc is corroded and swolled bursting the rubber cover seal allowing the ptessure to bypass to the vent line !!!!! wow you guys are great !!! now is there a rebuild kit available for the valve alone and who might have one ?? thanks again

 

[salvorone@aol.com]

here are the photos of the unloader and diaphragm

 

[groundog]

you can buy a new one at napa for about 25 dollars

 

[salvorone@aol.com]

anyone know the napa part number??

 

[airmech3839]

Glad you found the problem... Dont know the part number but a good napa clerk should be able to help you find the proper one.
post up what you find out incase someone else needs/has this problem!!

 

[rlwm211]

I did not thnk of this before but the deuce recovery thread may have the part number, or the deuce interchange parts list.

I believe these are in the Deuce forum under resources or FAQ

RL

 

[airmech3839]

I was going to say bad air compressor until I read this.......
What else do you think it could be? There are only two air lines running to- or from- the compressor. With eng. standing still the gov. control output (1/4" tube) should hold air inside, even at only 50psi. If both, gov. AND comp. are bad, some air could get into the engine's crankcase, but not a massive blow-by out of the breather tube.
Now, most Deuces I have worked on don't have that check valve in the main output line, at the entrance to the primary air tank so if the compressor head valves don't hold air it would blow past the comp. piston (s) & rings and down into the engine's crankcase through the oil return.

I've never had this particular (OP's) problem here, so I'm just guessing....

G.

I have never had this problem either. I understand your thoughts on the troubleshooting... and agree that the compressor could have been bad and blowing air into the breather... I am not an expert nor claim to be.. I was just thinking it could cause more problems with the system and possibly the engine..

We learn through experience and from others trials.. If the compressor had failed then other things should be checked for damage or problems.

 

[rlwm211]

I just checked bo0th lists and no joy on a part nuimber. You can try Saturn Surplus they may have the part.

RL

 

[gimpyrobb]

That part is from the newer style air pack. I have yet to see where parts for those are available.

 

[rlwm211]

Jeesh Gimpy you are absolutely correct. That is on the air side of the compensator. I just assumed he was in the "unloader" for the air compressor.

My suggestion is to get a kit and rebuild the entire airpack. If you have this much corrosion in the air control part of the air pack, the entire assembly is probably in need of rebuilding. You will have to bleed the brakes afterwards, so lay in a gallon of silicone brake fluid.

It is vitally important that you identify which air pack you have. The older style has a "can" on the back that is 6 inches in diameter and at least a foot long or so.

The newer style has the same diameter can approximately, but it is significantly shorter, probably 5 inches and there is a very long cast boss extending back from the rear cover and bolts the air pack to the support bracket.

I guess what I am saying is that the long airpacks are about 20 inches or so long and the shorter ones, excluding the extension are about 12.

Hope this helps...

Wow Gimpy, good call on this one!!!!

RL

 

[progun]

My truck does this too! Leaks constantly from the copper tube up by the air filter. Started on the way home from recovery. It changes tone when I apply the brakes. I guess i have the same problem. Gonna go open that up. Let me know if you find that P/N. I have the old style air pack I think.

 

[progun]

New style?

 

[rlwm211]

Yes, Progun...that is the new style. The telling point is the long "boss" that extends to the mount. The original long cannister ones had a piston assembly that extended to the bracket. Both work equally well, but the new ones are harder to find a rebuild kit for.

You may find the small bolts on the cap on the air actuator assembly are loose and can be tightened. Don't go crazy, they are 1/4" but that may help.

RL