MY Airpack Rebuild with Photos!

[crazywelder72]

Oh Sh.. I need to read this thread from start to finish tonight. Let me throw out a few quick questions about my current issue. (but i promise i will read it all)

the shortest version is my brakes are stuck on .

The brake lights are on so that makes me think the problem is in the airpack. If it was just a shoe sticking, the lights wouldnt be activated. The pedal is hard to depress but i can hear the air releasing when you let of the pedal.

I tried tapping on the airpack and hitting on the skidplate under it, to maybe jar something free but it didnt work .

WTF is going on?

 

[Mike O]

Did this happen after you had the airpack apart? I recently rebuilt mine and had the same problem. Turned out I had one part in backwards. Took about ten minutes to set it right and the problem went away immediately.

 

[crazywelder72]

no.. I haven't touched my airpack since i got the truck. It was working just fine earlier today.

 

[crazywelder72]

well i just ordered my airpak rebuild kit just in case. I found it online for $62. everybody else was selling the kit for over $100.

I know the guardians of the message boards frown upon listing where you bought it. so PM me if you want the info.

 

[crazywelder72]

well I opened mine up tonight and saw some gross stuff. It looked liked wax or a fatty substance was inside.

 

[Lonesome715]

Just wondring, how do you know if it has to be rebiult or has gone bad?

 

[crazywelder72]

my brakes started sticking, I could hardly move the truck. i had to crack the bleeder to release the pressure. I still dont know 100 percent if the airpack is the problem or the Master cylider, but i ordered this rebuild kit.

after seeing how gross this was inside i am glad i am doing it.

 

[Lonesome715]

I will have to pay close attention to mine when I get it going. So far the brakes look good.

 

[tuckered]

well I opened mine up tonight and saw some gross stuff. It looked liked wax or a fatty substance was inside.

That looks like some GAA (Grease: Automotive, Artillery), genuine GI issue. The gold color snaughty stuff anyway. The black stuff looks similar to used, dirty grease and the wet stuff may be water mixed with dirty grease that could have gotten hot.

Hard to tell. Real life is not the same as a photo.

Just an off the wall guess: The grease may have been to "prep" the seal like you would on an oil filter or fuel filter, but they used grease and way too much of it. Drying/damaging the rubber seal, which allowed water to seep in, while the truck was out swimming in a creek. But that is just a wild guess. Either way, when you able, you may want to check the other ones too. Since the other axles were with the truck when the stuff was "serviced" in the first place.

 

[Lonesome715]

That scares me becuase it is obvious my truck was taken swimming a few times.

 

[turbovr6jetta]

I would assume the "fatty" substance is an O-ring type of lubricant. Mine was the same except more of it. And you sould order some up for the rebuild. Parker O-lube is what I think I used. And I put it on thick. Its similar to the texture of petroleum jelly but a bit more stickey. It wont damage any seals. And let me know how the new paper gasket on the end of the airpack goes back on

 

[crazywelder72]

ahh I saw this a bit to late. I just got it back together not more than 15 minutes ago without any o-ring lube. Nothing in the TM's about the lube, only lubing the seals with brake fluid. Oh well.... guess time will tell.

oh..... and that endcap gasket was fun (but i did it without breaking it.)

 

[turbovr6jetta]

Thats pretty impressive. I soak mine for a while and got it on but it was so tight it rolled on me and broke when I tried to get it to sit flat. I also lubbed with brake fluid, but only the wet side of the air pack. I hope brake fluid is okay for those felts on the dry side. Im guessing your using silicone fluid? If thats the case Im sure its fine.

 

[crazywelder72]

yes Dot 5.

And special thanks to my friend "Boatcarpenter" for the printout with the correction on the 2 seals.

 

[crazywelder72]

Interesting update. even tho i replaced some wheel cylinders in the past I filled my master cyl with Dot 5. I had a friend working the bleeders and i told him to purge until good purple came out as i wanted to pump as much new fluid in. I also told him to tell me if anything but purple came out.

well he must have not heard a word i said.

Today i hooked up my pressure bleeder so i could do it m self. Had purple at the airpack but when i got to the right rear wheel (the first i was bleeding) It was Dot 3.

I had to purge for quite a while on all the wheels to get the Dot 5. If i didnt already have a master full of dot 5 and a freshly rebuilt airpack i would have flushed it.

I know its not the best way to do what i did but i didnt have enough fluid or cash to just purge it all.

anyhow I wonder if that fatty globs inside the airpack was a result of mixing Dot3 and 5 and any moisture.

 

[turbovr6jetta]

I doubt it. You would of had to have brake fluid in the airpack for that to happen. And like I say mine had the same stuff.. if it would of had globs of that crap on the wet side of the air pack then silicone and organic fuilds mixing could of been the cause. I'm sure that goop is a lubricant. You don't want those seals to be dry. That's why you have to lube the air pack every so often.

 

[DeucesWild11]

And let me know how the new paper gasket on the end of the airpack goes back on

Yeah I had a problem with that too. It was just too tight and then SNAP! I used a make your own gasket sealer, seemed to work out great!

Good luck!

 

[crazywelder72]

i was expecting mine to break and i was debating to either use some permatex or cut my own paper gasket.

I got lucky and didnt need to make that decision.

 

[doghead]

I soak mine in BFS for a good hour, before insatling it. It helps it "stretch" without tearing.

 

[hndrsonj]

Well on my pre-op for a T4T event, I had spongy brakes. Fluid coming out the slobber tube and vent. I have 3 spare airpacks sitting around with 2 rebuild kits. Picked the best looking and tore it apart. I found the main return spring installed incorrectly and a seal which appears too small (like post #3). I just need to hone the main body cylinder (since it sat without the stoplight switch in it) and reinstall. Whole thing start to finish I'm guessing will be under 3 hours. My question is: what is everyone using for a build lube? Dot 5 or vaseline? Book doesn't say but it really looks like vaseline.