FLU419 SEE HMMH HME Owners group

The FLU farm · Jun 8, 2018

I hope you have checked the notoriously bad/leaking drain valves, FarmMOG. I can see how high rpm could make one of them even less reliable than normal.
And as Pinsandpitons asked, even small air leaks are usually easily found by ear.

FarmMOG · Jun 10, 2018

Pinsandpitons said:
Given that the symptom starts when you use the high idle circuit, i would suspect the components involved there. Namely the tool circuit switch and the throttle air cylinder. Looking at the air system diagrams in the student handout available in the TM section might be helpful too.

Can you hear the leakdown?

It also happens without using the high idle circuit as well. I can hear air leaking in spurts from under the center area between the seats, as long as the doors and windows are closed. I have tried listening outside, but the exhaust is too loud and I can't get my head under the cab. I have gone over the student handout diagrams several times, and can see where everything is tied together in one system that doesn't work. It sounds like maybe a over pressure valve is releasing prematurely, but the only one I can find on the diagrams is at the air tank, and I don't think this is the problem.

FarmMOG · Jun 10, 2018

The FLU farm said:
I hope you have checked the notoriously bad/leaking drain valves, FarmMOG. I can see how high rpm could make one of them even less reliable than normal.
And as Pinsandpitons asked, even small air leaks are usually easily found by ear.

I have replaced all tank drains, along with blowing them out with compressed air. Next week I will be back at the farm and will try to go over everything again; hopefully with some better luck than before. I am thinking about filling the alcohol injector with some type of light lubricant and letting it go through the air system to hopefully lubricate all the gaskets and seals and maybe fix the problem for good.

The FLU farm · Jun 10, 2018

Why do you have the engine running when trying to listen for leaks??
If the leak(s) is so severe that it stops almost simultaneously with the engine, try feeding the system from an external source.

Oops. My reply was meant for post 3890.

tennmogger · Jun 10, 2018

FarmMOG said:
...I do have a quick question for anyone. I rebuilt several components in the air system and things work much better, except for the air supply for the transmission splitter, 4 wheel drive and hub lockers, and the remote throttle. There is a component that leaks sometimes and doesn't allow the system to build up pressure, then it seals itself somehow and everything works like it should for a while, then it starts leaking again. Anytime I use the rear hydraulics with the engine RPM running at 2000 for any length of time, the component leaks for a while. Does anyone have any idea what component might be the culprit? Thanks

---
It is probably not a coincidence that on a 406 Unimog those subsystems are all "beyond" the over-pressure valve. That's the valve that allows air to pass only after reaching a preset pressure. 70 psi comes to mind. The purpose, of course, is to delay supply to secondary functions to preserve primary functions, like brakes.

I had to replace the over-pressure valve on my LMTV a couple of times due to leaks, and guess what, it uses the same over-pressure valve design as the 406 Unimogs. I used a 406 OPV on the LMTV last time I fixed it. I looked at several here this evening and there were subtle differences in body shape but size and threads were the same.

The OPV is simple. Two screws and the cap comes off, but watch for the spring. The caps tend to warp and cause a leak, often pressure sensitive. I have made a thin paper gasket and used a little sealer to fix them

On a 406 the OPV is inside and near the left frame rail near the rear of the cab, "T'ed" into a main air line.

Bob

FarmMOG · Jun 11, 2018

tennmogger said:
---
It is probably not a coincidence that on a 406 Unimog those subsystems are all "beyond" the over-pressure valve. That's the valve that allows air to pass only after reaching a preset pressure. 70 psi comes to mind. The purpose, of course, is to delay supply to secondary functions to preserve primary functions, like brakes.

I had to replace the over-pressure valve on my LMTV a couple of times due to leaks, and guess what, it uses the same over-pressure valve design as the 406 Unimogs. I used a 406 OPV on the LMTV last time I fixed it. I looked at several here this evening and there were subtle differences in body shape but size and threads were the same.

The OPV is simple. Two screws and the cap comes off, but watch for the spring. The caps tend to warp and cause a leak, often pressure sensitive. I have made a thin paper gasket and used a little sealer to fix them

On a 406 the OPV is inside and near the left frame rail near the rear of the cab, "T'ed" into a main air line.

Bob

This was the last valve I rebuilt in the system before having all the problems. When I first installed it, I didn't have the pressure adjustment set correctly and had a little more air pressure than normal entered the secondary system. I quickly reduced the pressure to this system, but have had the issue ever since of it leaking periodically. I will try what Flu farm suggested and run air into the system from a compressor and check for leaks that way. Hopefully the culprit will be found quickly. It is good to know that these valves are interchangeable with the LMTV, as I would sure like to get one eventually. Thanks.

FarmMOG · Jun 11, 2018

The FLU farm said:
Why do you have the engine running when trying to listen for leaks??
If the leak(s) is so severe that it stops almost simultaneously with the engine, try feeding the system from an external source.

Oops. My reply was meant for post 3890.

I will try that when I get back over there. Thanks a million for the advice.

The FLU farm · Jun 12, 2018

Not that I've had the pleasure to use the FLUs much

lately, but today the HMMH came in very handy, again.
Set some posts for the carport that the FLUs will live in. Only fair that it participates in the building of its future house, I think.

Oh, and tomorrow

the Summer SEE will get used to compress the contents of a dumpster, so I can cram even more in there.

Pinsandpitons · Jun 12, 2018

So jealous of the HMMH.

On another note, the float function on my SEE requires that I hold the lever past the detent. Does everyones work that way? I would love the detent to hold the lever down for me. Thoughts?

The FLU farm · Jun 12, 2018

You could do a lot of the same things with a SEE's backhoe, just not with the same precision (with me operating it anyway) or reach.
Making a "Skyhook", like what I did with a Quick-Tach plate, but to pin in place of the bucket, would give you the reach.

As I recall, at least one of my levers do stay in the float position, most don't. Lube and tinker?

Pinsandpitons · Jun 12, 2018

Copy. Thats what i was looking for, whether or not it stays down for some of you or not. Ill look into it.

On the crane front, yes i was actually looking at fabing up a stinger to mount in place of the bucket, possibly with a winch on the end. As if i don’t have enough projects.

The FLU farm · Jun 13, 2018

Now that I think about it, since removing and reinstalling the bucket isn't that fun, maybe build something that can be pinned in using the bracket for the ripper?

And I can relate to wanting a winch, too. Except I'd want it on the crane.
Making a winch mount at the base looks doable, but I'm not sure about the forces involved as the cable would/should be routed along the existing boom and out to the end.
It'd be stupid simple to put a winch at the end of it, but I don't like the idea of running battery cables and one for the remote all the way out there.

Pinsandpitons · Jun 13, 2018

Yes, and at the risk of turning this into a modifications thread, the backhoe boom when fully retracted is pretty spongy so not the best foundation for a lifting device. I really just want the rear implement off an HMMH. I’ll give you $2000 for yours.

peakbagger · Jun 13, 2018

A few years too late, Expedition Imports had the crane and forklift attachment for sale a few years back. Jay Couch and C&C Equipment have complete HMMHs for sale (neither is cheap). I expect there probably are a few orphaned ones attached to trashed chassis from the Texas auctions out there its just finding them in good enough condition to reuse them.

The FLU farm · Jun 13, 2018

Pinsandpitons said:
Yes, and at the risk of turning this into a modifications thread, the backhoe boom when fully retracted is pretty spongy so not the best foundation for a lifting device. I really just want the rear implement off an HMMH. I’ll give you $2000 for yours.

Okay, I never thought I'd sell it, but make me an offer I can't refuse and you can have a whole HMMH, in darn near museum quality.
I could use the garage space.

Pinsandpitons · Jun 13, 2018

I think given how often you’ve written “i cant believe i ever got by without a crane” or something similar, the offer you cant refuse might be one i would refuse to make.

The FLU farm · Jun 13, 2018

Notice that I've written "I can't believe I ever got by without A crane." So far I have yet to use the spare one.

Pinsandpitons · Jun 13, 2018

I hadn't realized your addiction had progressed that far... I should heed your implicit warning, I have far less garage space than you.

The FLU farm · Jun 13, 2018

Hey, I even sold a SEE a while back, so I'm down to five FLUs.
Anyway, the HMMH I'm using is far from museum quality (first hint) and while it lives under a roof of sorts, it's not garaged (second hint).

coder123 · Jun 16, 2018

I have a FLU SEE and will post all my info soon. Wondering if anyone knows where i can get the 4 wd selector. Can’t find one anywhere

FLU419 SEE HMMH HME Owners group

Well-known member

New member

New member

Well-known member

Well-known member

New member

New member

Well-known member

Active member

Well-known member

Active member

Well-known member

Active member

Well-known member

Well-known member

Active member

Well-known member

Active member

Well-known member

New member