Brakes locked-in driveway!!

[Boatcarpenter]

Air pack rebuild time. Damn, just lubed it not long ago. Presume the whole unit must come out. Does just pulling the end plate give access to what needs fixing even though it will be awkward working on it? Or just pull the whole thing and go through the brake fluid portion on the front of it also. I know it has been discussed but haven't found thread yet.
Thanks for any tips and tricks.

 

[cranetruck]

Did you get the brakes to release? Open the left rear glad hand (service) air connector to release the brakes if they are locked due to an airpak valve malfunction.
If you decide to rebuild, take the whole thing off. You will need to disconnect air lines, but otherwise it can be done relatively easily.

More info to come if/when needed.

Bjorn

 

[Boatcarpenter]

I drained the tanks to see if the brakes would release, they didn't. Didn't know about opening the rear glad hand. Anyway, it's out and on the bench. I have a TM that tells me how to R&R it but I don't think I have an exploded diagram for it. But I'm still looking. Will let you know how it goes.
Thanks,
Prentice

 

[cranetruck]

MVM June 2002. Article on airpak rebuild with lots of pictures.

Bjorn

 

[Boatcarpenter]

Tear down successful. No broken, bent or otherwise trashed parts. No rust, no pitting, no scoring on the main chamber walls. Nothing seemed jammed or immoveable but when one takes things apart they never are. LOTS AND LOTS of grease globules everywhere. Must have been oil and grease that ended up getting compressed into globs from the air pressure and movement. Trying to put a couple of pictures on but I have to change format I think.
Finally got pics rezized and uploaded.

 

[cranetruck]

Great sergeant, make sure that the U-cup seals get put back with the "cup" facing the higher pressure. One manual shows one seal incorrectly, so put them back the way they came out (you took notes, right?).
I found that one had to be careful with the long spring inside the slave cylinder so that it wouldn't kink, especially if you don't have a spare, like from the rebuild kit.

Bjorn

 

[Boatcarpenter]

Will be going back together today with cups facing right way. Took notes and pics. Added two pics to my previous post.

 

[mangus580]

Boatcarpetner... if you want... type up a little article with pics on how you did this.... (you can do it in word, and PM me with it if you want....) I will put it in our tech articles for everyone

 

[Boatcarpenter]

Bjorn, Help!!! I was cleaning the sub-master cylinder portion of the unit and you guessed it, one cup, a double coil spring retainer cup, (for lack of anything better to call it), and two long coil springs, one inside the other took off accross the room before I could grab them. As they flew by I tried to see what way everything was facing but it didn't work so good. I have posted a picture the way I think they should go. The rubber cup on the right I took out so I know that one is correct. The plunger body I took out also so I know that is correct. The second cup from the right I believe is correct also as I had seen the flat side of it when I looked in the bore after I had taken the first two items out. Logically, the concave side of the spring retainer cup has to face the springs and the smooth side sits in the rubber cup. Does that seem proper from any diagrams that you have. My big question is whether or not there are parts I didn't find after their hasty exit from the cylinder. How does this all look to you?
Thank you very, very much for any input.

 

[cranetruck]

I'll go and get some pictures.
Meanwhile clean the piston, it should be shiny aluminum and the valve inside must be functional.
Bjorn

 

[cranetruck]

Hope this helps.

 

[Boatcarpenter]

Perfect Bjorn, thanks much. I took everything out from the other end and I believe that each cup can be put in from the appropriate end so no danger of rolling over.
No parts missing so back together she goes as all o-rings, cups etc. are good and everything is all clean. Thank you very much. Prentice

 

[Boatcarpenter]

Maybe this is what happened

Perhaps this explains all the globules of stuff in the various chambers of the airpack.

 

[Boatcarpenter]

Any chance of getting a good reproduceable copy of the airpack vent upgrade into yhe Tech Articles section?

 

[cranetruck]

Is this what you are looking for? If it is, I can send a high res version to Mike. The full story is actually 3 pages long.

The breather valve in the picture should be mounted vertically to prevent water from collecting and possibly freezing.

Just to be different, I pulled a separate dedicated line from the airpak to vent it. It's really the "exhaust" from the airpak.

Bjorn

 

[Boatcarpenter]

Thanks Bjorn, it's legible

 

[cranetruck]

Here are the preceeding two pages:

Bjorn

 

[Boatcarpenter]

Can anyone tell me if the Mil. DOT5 brake fluid is purple like the civvie DOT5 is?

 

[Boatcarpenter]

Well, just back from a test drive down the steepest hill I could find close to home and I am happy to report that the brakes work great!!!!

 

[Recovry4x4]

Can anyone tell me if the Mil. DOT5 brake fluid is purple like the civvie DOT5 is?

Sorry, missed this question earlier. The answer is yes, and no! I've seen both. The bottle I opened yesterday looked to be purple but when I dumped it in the bleeder, it was almost brown. Once it was in the system it turned that familiar yellow in color. The previous gallon I opened was in fact purple.