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Thought it would be useful to start a new thread on the air pack rebuild (attempt)
I was loosing DOT 5 brake fluid while the truck was parked for two years. No visible leakage. In the end decided to bite the bullet and got the MC and the air pack out on the bench.
With the AP, all the air lines looked dry initially and not rusted, so I hoped I could get away with some small repairs. Then I had the AP upside-down and turned a few times, and a milky fluid started coming out of the air-vent T connections on top, but not out of the two other air connections lower on the diaphragm thingsy in front.
![AC-rebuild-02cr.jpg AC-rebuild-02cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485537-be537eee02792af5ba5caacbeb8b4674.jpg)
Out of the slave hydraulic cylinder came clear blueish transparent DOT 5.
No fluid came out of the open rear-end air connection!
So I took of the air cylinder part to see what was there. When taking it out, the parts were on an angle with each other, so any liquid that was in the intermediate section with the spring would run into the rear air section.
Taking everything apart, it looks like somebody put a lot of heavy grease on the seal. I think that, until today, the rear section was without liquid, given the fact that no liquid came out of the rear air connections, and the rear section has a lot of yellowish grease, also on the seal (pic left). On the other hand, in the part with the spring (pic right), there was a murky more grayish grease and the milky liquid and other stuff on the walls and spilling out on the table.
![AC-rebuild-13cr.jpg AC-rebuild-13cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485534-02adb1a807f236a17ca3cad97c8e505d.jpg)
Most of the liquid spilled on the table when opening the air cylinder, but some of it probably went into the air section, because there was a milky liquid in there as well, but with yellowish untainted grease.
![AC-rebuild-18cr.jpg AC-rebuild-18cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485532-93f4bd3ecbcf0186ce0d0a68da109af8.jpg)
So I will have to take the rest apart as well and rebuild the thing, but I have to get parts from the Netherlands for that. Will cost me 55 EUR, and hoping they have the proper set for the M39 AP and not the Deuce long AP.
I was loosing DOT 5 brake fluid while the truck was parked for two years. No visible leakage. In the end decided to bite the bullet and got the MC and the air pack out on the bench.
With the AP, all the air lines looked dry initially and not rusted, so I hoped I could get away with some small repairs. Then I had the AP upside-down and turned a few times, and a milky fluid started coming out of the air-vent T connections on top, but not out of the two other air connections lower on the diaphragm thingsy in front.
![AC-rebuild-02cr.jpg AC-rebuild-02cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485537-be537eee02792af5ba5caacbeb8b4674.jpg)
Out of the slave hydraulic cylinder came clear blueish transparent DOT 5.
No fluid came out of the open rear-end air connection!
So I took of the air cylinder part to see what was there. When taking it out, the parts were on an angle with each other, so any liquid that was in the intermediate section with the spring would run into the rear air section.
![AC-rebuild-04c.jpg AC-rebuild-04c.jpg](https://www.steelsoldiers.com/data/attachments/485/485536-ce054d38c6e8983a1c1fe1007d1fa48b.jpg)
Taking everything apart, it looks like somebody put a lot of heavy grease on the seal. I think that, until today, the rear section was without liquid, given the fact that no liquid came out of the rear air connections, and the rear section has a lot of yellowish grease, also on the seal (pic left). On the other hand, in the part with the spring (pic right), there was a murky more grayish grease and the milky liquid and other stuff on the walls and spilling out on the table.
![AC-rebuild-15cr.jpg AC-rebuild-15cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485533-10588d98d28610a4ea444ae575ca7ae7.jpg)
![AC-rebuild-12rc.jpg AC-rebuild-12rc.jpg](https://www.steelsoldiers.com/data/attachments/485/485535-8afd0a0fa1cf1a0a294192d7621117c1.jpg)
![AC-rebuild-13cr.jpg AC-rebuild-13cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485534-02adb1a807f236a17ca3cad97c8e505d.jpg)
Most of the liquid spilled on the table when opening the air cylinder, but some of it probably went into the air section, because there was a milky liquid in there as well, but with yellowish untainted grease.
![AC-rebuild-18cr.jpg AC-rebuild-18cr.jpg](https://www.steelsoldiers.com/data/attachments/485/485532-93f4bd3ecbcf0186ce0d0a68da109af8.jpg)
So I will have to take the rest apart as well and rebuild the thing, but I have to get parts from the Netherlands for that. Will cost me 55 EUR, and hoping they have the proper set for the M39 AP and not the Deuce long AP.