Critical FMTV PM not covered in TMs

[Awesomeness]

DO NOT use skydrol (aircraft fluid)! This will ruin the entire system! If the system isn't designed to use Skydrol it will eat and destroy every part in the system that isn't metal! (I work at a major aircraft company and see what skydrol does to stuff... and that is turn stuff to goo rubber, plastic, paint)

I figured out you can by hydraulic oil by the gallon and 5 gallon pail. I just added some to bring the level back up. I'm not going to buy any special fluids unless it's required. It's actually novel to be able to buy fluids anywhere.

The system is designed for the aircraft fluids that Aleigh listed, and you DO want to use them. They contain corrosion inhibitors that will keep the system from rusting out from the inside, as a number of owners have found while using regular hydraulic fluid. There is no particular design flaw that allows water in (as Aleigh suggested), because there is supposed to be a metal cover over the whole rear portion of the pump that shields the vent... if you're missing it then that is your problem.

The fluid is more expensive than regular tractor hydraulic fluid, but not a big deal in the context of everything else on this truck. I think I bought it online for $6/qt, and the whole system uses 3qt. I think I got free shipping at $50, so I went ahead and bought 9 quarts, and have enough for a very long time now.

 

[deshet]

Thanks

 

[deshet]

where can I find the piston? My seal was broken but the Piston inside was broken in 3 places.

Thanks

 

[Aernan]

where can I find the piston? My seal was broken but the Piston inside was broken in 3 places.

Thanks

I don't think you can buy the piston by itself. best to buy the whole assembly.

 

[Awesomeness]

where can I find the piston? My seal was broken but the Piston inside was broken in 3 places.

If you have trouble finding a piston, you could always get one made. It's not a very complicated part. We would just have to measure up an existing one, and make a model/drawing for it. For what some people want for the whole latch, or other parts, it still may be a cheaper way to go.

 

[deshet]

It is actually the spring that is broken. I wonder if something automotive would work.
Where can I buy the kit worse case?

Thanks

 

[Awesomeness]

Can you find a die spring on McMaster, or at Lee Spring, to replace it?

 

[VertigoPilot]

Welcome and good luck.

That should be a sticky! Maybe even a forum mantra!

 

[coachgeo]

That should be a sticky! Maybe even a forum mantra!

use your bookmarking tool to come back to it when needed?

 

[VertigoPilot]

use your bookmarking tool to come back to it when needed?

My comment was intended as levity, mostly.

 

[JD4044M]

Great thread, I think this is my problem with the latch not opening and causing the hydraulic pressure to build to high and blew a seal on the latch. The hand pump works good it can put out great pressure! Air Pump spins nice with air real and coasts down for a while till it stops. It was clean and so was the sump. Spare tire works the way it should and that leaves only the latch where the fluid came from. I will pull the latch apart tomorrow and deal with the seals. Guess the fluid is/was the right color.

 

[JD4044M]

Got my O-Rings replaced Cab Tilt works great now and no leaks!

 

[Primussucks]

Just stopping by this thread to say "Thank you"
New to me m1078a1r.
Attempted to raise the cab and was greeted with a hydraulic fluid shower spraying from the latch pin.

Lowered the spare tire out of the way.
1 3/4" socket on the end cap as described. Removed end cap, wiggled the cylinder out to find a dry rotted oring.
Replaced with a new oring... Mine accepted a different size then what was originally called out in this thread. "214" / P25 seemed to do the trick.
10 mins later it is all back together and I can raise the cab again. Shower free.

Thank you to this tremendous resource.

 

[CallMeColt]

Just stopping by this thread to say "Thank you"
New to me m1078a1r.
Attempted to raise the cab and was greeted with a hydraulic fluid shower spraying from the latch pin.

Lowered the spare tire out of the way.
1 3/4" socket on the end cap as described. Removed end cap, wiggled the cylinder out to find a dry rotted oring.
Replaced with a new oring... Mine accepted a different size then what was originally called out in this thread. "214" / P25 seemed to do the trick.
10 mins later it is all back together and I can raise the cab again. Shower free.

Thank you to this tremendous resource.

You still want to service it with a complete kit. If one went bad, the others will. And getting the correct o-ring on there is important or it will fail quickly. I did that. Use what you have to get it going for now but rebuild it fully. It's not worth getting stuck with it leaking when you need it to work. Happened to me & I left Wal-Mart with a nice puddle when I went to check something after a different service.

 

[hike]

Just stopping by this thread to say "Thank you"
New to me m1078a1r.

Thank you to this tremendous resource.

Welcome!