6x6 only engaging in reverse

[nf6x]

That stinks that they don't sell the rebuild kit any more. I see that there's a copy of the parts diagram with the seals highlighted in the sprag thread linked to above. The seals pictured there look like cup seals. If they're standard common sizes, then it's possible that an industrial supplier like McMaster-Carr will have suitable replacements.

 

[MyothersanM1]

When I called them last week they had told me they stopped making the rebuild kit and just sell the whole cylinder now which kinda sucks

That definitely sucks. I just bought the kit back last October. Looks like someone got the bright idea that one could be charged more for the whole assembly rather than the rebuild kit. The McMaster-Carr idea is a good alternative. They are my go to place for odd-ball parts.

 

[wdbtchr]

There's a thread on here somewhere with me going through the process of getting my M51a2 6X6 working. I did the whole thing with the diesel in the xfer case, rebuilding the poppet valve, replacing the poppet valve, and getting a kit to rebuild the cylinder. AS my luck works out it turned out there was a grove rusted in the bottom of my cylinder and I had to replace the whole thing. Good news is it now works as it's supposed to, it just took me 6 months to work through they process.

 

[seano11]

There's a thread on here somewhere with me going through the process of getting my M51a2 6X6 working. I did the whole thing with the diesel in the xfer case, rebuilding the poppet valve, replacing the poppet valve, and getting a kit to rebuild the cylinder. AS my luck works out it turned out there was a grove rusted in the bottom of my cylinder and I had to replace the whole thing. Good news is it now works as it's supposed to, it just took me 6 months to work through they process.

That is the reason I'm just gonna go with the whole new one my luck would be the cylinder would be bad and I'd have to wait another 2 week for more parts

 

[nf6x]

In that case, I'd rebuild the old cylinder after doing the swap and keep it around as a spare. Then the truck won't be down while you're looking for parts and working on the old cylinder.

 

[ChuckM]

To check the cylinder seals....take both cylinder lines loose from the poppet. Rig up an independent air line (say from your shop compressor) to the forward sprag line, pressure it up and check for air leaking out of the reverse side. At this time you can also jack up one tire and check to see if the sprag engaged.

 

[seano11]

well the new one arrived today was not easy getting the old cylinder off the shaft had to use a gear puller and it pretty much destroyed the old cylinder so no rebuilding that one lol anyways will let everyone know if it works or not once I get it back together

 

[MyothersanM1]

well the new one arrived today was not easy getting the old cylinder off the shaft had to use a gear puller and it pretty much destroyed the old cylinder so no rebuilding that one lol anyways will let everyone know if it works or not once I get it back together

Sorry to hear you couldn't save the old cylinder. When I took mine off it gave me no problem at all.

 

[seano11]

Well it's all back together not sure if it's working I have a 1/4 inch plastic airline running to the poppet valve instead of the bigger rubber one I think I might be loosing some air pressure by having it set up that way because the clunk can only be heard with the truck off . The new cylinder ce with the wrong size shaft nut so you have to reuse the old one . I'm gonna put a larger airlIne to the poppet valve in the am and then go hook the truck up to a tree and see if the 6x6 is working

 

[Floridianson]

When air is leaking from the poppet exhaust the sprag cyl is leaking. The cyl. should come off with little trouble and after removing the nut that holds on the piston you might have to unscrew the pistion from the sprag shaft as the internal seal catches on the shaft. I dont think we are going to find these seals in the aftermarket but hope we can or someone does. Also it helps to remove the cyl. when the piston is left in or shut down the truck in reverse aired up.

 

[seano11]

If anyone wants the old seals before they tare into there set id glady mail them so they could pre search For new ones

 

[Floridianson]

Forgot to say you remove the cyl. first on takeing it apart then remove the nut and piston. Then on replacement you replace the piston and cyl. already put together then the nut.

 

[seano11]

Ok guys new air cylinder is on new poppet valve is on still getting air leaking out the exhaust port and only get a clunk once and awhile I'm gonna go hook it up to a tree now and see if the front wheels will pull

 

[seano11]

Ok so I have 6wheel drive in forwards and backwards now I still get a air leak out the exhaust port it's ever so slight is this normal ?

 

[Squirt-Truck]

No,
If you have enough leakage in the poppet valves to hear over the engine the valve seals are not seated.
Have you opened it and made sure the internals are clean? That the seats are not cut? That the seals are good?
What may appear as leakage at the poppet can be blow through at the transfer shift cylinder. This can be checked by pulling the hoses one at a time.
Sometimes the new seals need to "wear in".

 

[seano11]

No,
If you have enough leakage in the poppet valves to hear over the engine the valve seals are not seated.
Have you opened it and made sure the internals are clean? That the seats are not cut? That the seals are good?
What may appear as leakage at the poppet can be blow through at the transfer shift cylinder. This can be checked by pulling the hoses one at a time.
Sometimes the new seals need to "wear in".

I no I can't ever hear it leaking when the truck is shut off but when you spit into it it will ever so slowly blow a bubble I just thought with all new poppet valve and air cylinde that it wouldn't leak at all

 

[Floridianson]

I might think if is realy just a bubble leave it alone. Maybe put some air tool oil in the system.

 

[MyothersanM1]

When I reassembled my cylinder and piston, I made sure to lube it with some light oil. It helped with assembly, especially the cup seals, and ease of operation. I replaced all the rubber declutch hoses with new from Memphis. For added measure, I Teflon taped all pipe thread joints (not the air brake type compression fittings). I have no air air leaks anywhere in that system and I get a strong "PFFT-Thunk" every time, reverse and neutral.