agazza2
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- Ahwatukee, AZ
Thought I would start a post on my FMTV on some of the repairs and upgrades to keep track of things and provide insights to others that have FMTVs. I have had my M1078 for about two years now, and it seems like there is always something to rebuild to get it back to optimal running condition. Same repairs as most owners have already done on here. I plan on adding additional information under these topics as time permits.
Some failure items on FMTVs due to either sitting, or not being fully maintained.
1. Protection valve seals (above rear axle) - air leaks from dry rotted seals
2. Air protection valve by battery box - seal leaks
3. Service brake valve leaks - air leaks due to loose fittings
4. Front axle growl - bearing clearance adjustment
5. Hydraulic pump failure - hydraulic fluid coming out vent valve
6. Hydraulic Manifold failure - cab raises 6"10" then locks
7. Cracked timing cover - due to loose air pump bolts
8. Unusual tire wear
9. Door handle replacement - upgrade to A1 handles
10. Front driveshaft wear
11. Upgrades
I will start with the Hydraulic manifold as it has given me the worst issues. After I rebuilt the hydraulic pump due to hydraulic oil coming out of the vent, everything worked fine for two weeks. Then the cab would only raise about 6-10" and then lock up, and would not go any further. If I used the manual pump it would do the same thing, and at this point you could not even move the hand pump lever. If you slightly cracked the return line on the hydraulic cylinder for the cab it would lift just fine.
After replacing all the seals in the manifold, from Martin Fluid Power (MFP) it still did the same thing. So I finally decided to build a new system using a 2 spool hydraulic valve system. While waiting for a few parts for this system to come in, I was able to find a FMTV 5 ton manifold that was used from 2008 - 2013 (4130-01-527-8543). This one does not have the air lift valve for the cab lift. I installed this one, and will move the air cab lift switch inside the cab. Here are a few photos of the 2 spool system I tested in the garage today, and a photo of my new intended use of this system.
For those that have bad manifolds and do not want to pay the high price for a replacement manifold, the 2 spool is a great solution at an affordable price. You will need to purchase two air valves.The valve I will use for the air ride cab is also pictured.
![20180402_171256.jpg 20180402_171256.jpg](https://www.steelsoldiers.com/data/attachments/496/496380-9344bd1cdd99cadcb58e5578344274b8.jpg)
![20180402_171250.jpg 20180402_171250.jpg](https://www.steelsoldiers.com/data/attachments/496/496379-44dab4e08d325ac668586864e43092aa.jpg)
![20180402_171544.jpg 20180402_171544.jpg](https://www.steelsoldiers.com/data/attachments/496/496381-cce2098ef472d7ec6b89f4b2ad4a8970.jpg)
![20180402_172559.jpg 20180402_172559.jpg](https://www.steelsoldiers.com/data/attachments/496/496382-501a0fe171457ba9252db16d08326567.jpg)
Some failure items on FMTVs due to either sitting, or not being fully maintained.
1. Protection valve seals (above rear axle) - air leaks from dry rotted seals
2. Air protection valve by battery box - seal leaks
3. Service brake valve leaks - air leaks due to loose fittings
4. Front axle growl - bearing clearance adjustment
5. Hydraulic pump failure - hydraulic fluid coming out vent valve
6. Hydraulic Manifold failure - cab raises 6"10" then locks
7. Cracked timing cover - due to loose air pump bolts
8. Unusual tire wear
9. Door handle replacement - upgrade to A1 handles
10. Front driveshaft wear
11. Upgrades
I will start with the Hydraulic manifold as it has given me the worst issues. After I rebuilt the hydraulic pump due to hydraulic oil coming out of the vent, everything worked fine for two weeks. Then the cab would only raise about 6-10" and then lock up, and would not go any further. If I used the manual pump it would do the same thing, and at this point you could not even move the hand pump lever. If you slightly cracked the return line on the hydraulic cylinder for the cab it would lift just fine.
After replacing all the seals in the manifold, from Martin Fluid Power (MFP) it still did the same thing. So I finally decided to build a new system using a 2 spool hydraulic valve system. While waiting for a few parts for this system to come in, I was able to find a FMTV 5 ton manifold that was used from 2008 - 2013 (4130-01-527-8543). This one does not have the air lift valve for the cab lift. I installed this one, and will move the air cab lift switch inside the cab. Here are a few photos of the 2 spool system I tested in the garage today, and a photo of my new intended use of this system.
For those that have bad manifolds and do not want to pay the high price for a replacement manifold, the 2 spool is a great solution at an affordable price. You will need to purchase two air valves.The valve I will use for the air ride cab is also pictured.
![20180402_171256.jpg 20180402_171256.jpg](https://www.steelsoldiers.com/data/attachments/496/496380-9344bd1cdd99cadcb58e5578344274b8.jpg)
![20180402_171250.jpg 20180402_171250.jpg](https://www.steelsoldiers.com/data/attachments/496/496379-44dab4e08d325ac668586864e43092aa.jpg)
![20180402_171544.jpg 20180402_171544.jpg](https://www.steelsoldiers.com/data/attachments/496/496381-cce2098ef472d7ec6b89f4b2ad4a8970.jpg)
![20180402_172559.jpg 20180402_172559.jpg](https://www.steelsoldiers.com/data/attachments/496/496382-501a0fe171457ba9252db16d08326567.jpg)
Attachments
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Prince MB21BB5C1 Directional Control Valve, Monoblock, Cast Iron, 2 Spool, 4 Ways, 3 Positions, .JPG20 KB Views: 51
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