Spare Tire Hydraulics

[acropilot]

New member and a new owner of 2005 M1083A1. Awesome truck
In the process of getting my CDL since i live in CA. So, I don't have a driving report yet. Unfortunately i have to wait till 1/8/16 to do my driving test. I already took the written and good to go.

I have been going through the truck and testing things and fixing minor items as i find them.

1. Already replaced the Air Dryer Desiccant cartridge and the purge valve from Haldex.

2. Fixed the passenger door latch connecting rod. Found one on Ebay for $3.50

I have a question for the forum.

Testing the hydraulics on the truck...., the cab goes up and down no problem. However I had a hard time actuating the spare tire down and then up. I was able to do it once, but now it doesn't work. When i select the switch, it move a couple of inches and then it stops. (Same action whether via hydraulic manifold or the manual pump). I have read through the TM's and have conducted the following:

1. Checked fluid level in the Air/Hydraulic power unit. It is good.
2. Removed the Spare tire knob from the hydraulic manifold. Didn't see any thing clogged. Cleaned and put back in service.
3. It then asks for me to check the pressure in the hydraulic cylinder (To determine if it is the cylinder or the hydraulic manifold problem) while actuated. Not very accessible to measure the pressure in the cylinder with the tire still in the cradle.

Talking to some Army buddies, they tell me that it is more than likely the Hydraulic manifold. Any ideas on who the manufacturer is? I have contacted Oshkosh, but they haven't been able to provide any answers yet. Very pleasant though.

Any suggestions or inputs would be much appreciated.

Tony
310-628-0724

 

[Suprman]

I believe the manifold is rebuildable. Most stuff on the truck is. I do have an extra complete manifold but they are not cheap.
Will

 

[acropilot]

Is it for sale? Brand new?

 

[Suprman]

Good tested used from a truck I parted. The truck went thru depot maint in 2001

 

[NDT]

If it were me I would remove the line from the hydraulic cylinder that is not pressurized when lifting the tire. Remove the line where it is attached to the manifold. Put the end of the line in a coffee can or something. Attempt to lift out the tire. If when the tire stops moving, you are still getting large amounts of oil from the line, the cylinder is bypassing and needs rebuild. If the flow stops, the manifold is to blame.

 

[Suprman]

I have a good cylinder too.

 

[acropilot]

Yes. I actually dropped the fuel tank so i can access the back of the manifold. I swapped the lines between the cab and the spare tire. The cab still worked. So it is definitely the cylinder. I have a shop here locally in LA that can rework the cylinder for me. Having said that, How much do you want for your spare cylinder Superman?

thank you.