FLU air compressor, what actuates compressor? (and other air system questions)

alpine44 said:

Yes, Wes mentioned that he saw several hundreds on another lot. If and when they come to auction is anyone's guess.

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GP is letting them age, like good wine.

Here is my final plumbing, WAY simpler than the factory mess. The red line is the feed coming from the regulator which I was able to adjust down to release at about 105 instead of 120. Leaving the one line pictured disconnected effectively deactivates the trailer brake system. No more leaking valve at the steering wheel, and no more leaking valve to engage brakes in below the shifters. My mog actually HOLDS air now, after about 30 minutes of sitting it still has 60-70 psi in it, before it would empty the tank in minutes.

Swapped the high pressure safety valve for the one off the other tank which fixed a leak. In over an hour it has leaked down from 105psi to about 90psi. I am pleased with that to say the least.

Still had 30psi this morning, this thing holds pressure great.

I installed a new 4wd selector, it is plumbed up with one valve, so when engaging 4x4 it locks the differentials as well. There may be times I could use 4x4 without locking the diffs but if that time comes and it is annoying I will add in another valve. As you can see I made a new plate, got rid of the air brake valve and the STE/ICE wiring, I will never use it anyways.

NewEra said:

Still had 30psi this morning, this thing holds pressure great.

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Glad you have found a solution that works for you. Many others have similar abilities to hold air pressure while maintaining full features, just by fixing air leaks. I have found the turning radius in 4wd with lockers engaged is reduced due to binding on packed dirt and grass. Also ensure you are using appropriate regulators spas not to send too much air pressure to the axle pressurization system.

I did not remove the regulator that feeds air to the diffs. If it hadn't been leaking when I got it I probably would have left it alone, but there was no sense (for me) to fix the air leaks (spending at a minimum $100 probably for new hand valve and control valve, and $300+ for the 4wd selector) when I have absolutely zero need to ever pull a trailer with this thing. It barely pulls itself at 30-35mph as isn't the most stable vehicle in the world.

NewEra said:

I installed a new 4wd selector, it is plumbed up with one valve, so when engaging 4x4 it locks the differentials as well. There may be times I could use 4x4 without locking the diffs but if that time comes and it is annoying I will add in another valve. As you can see I made a new plate, got rid of the air brake valve and the STE/ICE wiring, I will never use it anyways.

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Good use of a simple Class 8 valve! I should copy that idea, but will definitely separate the 4WD and locker functions.
Not only is it hard on the components to run locked, but I like the extra traction to be available as an option. In other words, I run 2WD until that doesn't work, then 4WD.
When 4WD doesn't do it, the lockers are my ticket to not getting stuck. Usually.

I agree. I will very likely add another valve like the one above for the lockers. The good thing about how I did it is I can just run the line off the 4x4 valve over to a locker valve, that way the locker cannot be engaged until it is in 4x4. The BAD thing about all this is it is a PAIN to get to it all... Why they didn't make that center panel removable I will never understand, if you could take it out from the top just think of how much easier it would be to work on...

Hmm. My preference would be to have the front and rear lockers separately activated, and independent of 4WD (which I'd like to make lever operated).
Partially because I'm used to running 2WD low range in my Jeep, with a Detroit in the rear.
Another reason is that it can be beneficial to have the front or rear end slide slide sideways due that axle being locked. There are times when that can put you in a less bad situation.

Why they made it such a pain to get to is beyond me. Either I'll make the panel easily removable, or everything will be mounted on top of it.

For a true off-road truck I agree about having more options. For what I will be using this for it should not matter. I do want to eventually take the hoe/loader off and take it wheeling though to see how it does.

Well, I don't know if my use qualifies it as a true off-road truck as I do take it on the occasional 1 1/2-mile drive drive on pavement.
Normally it's used to dig ditches, move dirt and rocks, lift things, plow snow (technically blow snow, as I replace the loader bucket with a snow blower in the winter), and even for burying horses. Stuff one would do with a regular backhoe.
So far it's been stuck good two times, but I'm sure there will be more. Even though getting rid of the stock Michelins may have cut the risk in half, and I have much ​better snow chains for it now.

Noob question here.
To get 95psi in the front, or large tank, I had to adjust the regulator for the rear tank almost all of the way in. I could find no way to build pressure in it, so I am suspecting a large leak somewhere downstream.

What will I lose by not having pressure in the rear tank? Just trailer brakes?

Thanks,

Jim

You may want to take a look at the various air system schematics in the Student Handout to understand how the air system works

https://www.steelsoldiers.com/showt...cavator-flu-419-manuals-and-a-student-handout

As far as I can see, it only affects the trailer air supply.
Thanks.
Jim
https://www.steelsoldiers.com/showt...cavator-flu-419-manuals-and-a-student-handout[/QUOTE]

That's what it looked to me but I would much rather hand someone a link to the schematics.