Guys...how long has the AMK unit been around? ....curious why you are saying it's better per se.

 

Been available as a replacement on 05-09 my vehicles since this past September/October. The unit itself is much better in design, runs cooler, compresses more efficiantly, is quieter, far less prone to failure. It is the same unit that is installed from the factory on 2012 and up my trucks(there's been an update to its exhaust valve, but same basic unit.) I have yet to see one, with the updated valve at least, fail.

 

...but that's kind of my point, Dave. It hasn't been in service long enough for you to really collect enough meaningful data to compare reliability to the Hitachi unit.

I'm all for it being better, and I'm not arguing with you...just curious about how we know about its performance.

Maybe I'm looking for an upside to having to mount a compressor with a big, stupid aluminum bracket that will cause me to modify my rock sliders!!!

 

It's been in service for a year and a half, and aside from the exhaust valve issues, which have been taken care of on any that can be purchased now, I have not seen one replaced. After the same amount of time with the Hitachi unit, i could by no means say the same. I have completely disassembled both units, the AMK has better bearings, a better piston seal, much better machining on the valves, the motor winding is much cleaner and far more windings, and the rare earth magnets inside the AMK are some of the strongest I have ever seen inside a motor.
Quite honestly, the Hitachi unit is junk, its poorly built, and cheaply made.
I can not say how long the AMK will last for, but if build quality and overall manufacturing mean anything, I'd be willing to bet a pretty long time.

 

While I am sure the rock sliders are a pain for you, screwed compressors are probably in the "needs of the many outweigh the needs of the few" category ;-)

I agree we may not be statistically ready to say it wins, but I believe it was standard equipment from the assembly line on several years of LR4 and RRS.

Oh and you can't order a replacement Hitachi now. AMK is all the parts counter has to offer. Having compared them side by side (although I didn't do a full Dave autopsy) I am happy with my choice and have one more box ticked off on the things to worry about sheet. I might be almost complete ;-)

 

Okay....I give.

Thanks for the response. Dave, those were nice details. I will improvise a solution to my sliders. Maybe improvise the AMK mounting bracket!

 

Thanks for the replays called and have an appointment next week in Reno...Brian my mechanic may just be at a 4x4 event lol .....he did talk about the new compressors and would recommend if it IS a replacement issue. He did discuss a sticky relay but needs to figure out the issue. All information was very informative and thank you for the comments I will post next week with what he discovers. Giving a shout out to Brian the owner of British 4x4 of Reno Nevada if you need a guy that knows his stuff, is Fair and very conscientious ..... He's the one.....also going for the transmission fluid change too.....thank you for helping this newbie out!!
Cathy

 

Let us know how it turns out, and again, it is ok to drive the truck, just take a quick look before you get in it to make sure it's right around where it usually sits. No need to measure or anything, just close is fine.

 

I drove mine for a couple of days (as needed while I was waiting for the new compressor to arrive) while she was resting on the stops (not sure how/why she went all the way down when the compressor gave up the ghost)...it's quite a bit bouncy (rides like a tank with no suspension), but didn't seem to hurt anything, and the new compressor install brought her back to life with no (evident) issues from having done so.

 

There are many ways for the compressor to fail. If the exhaust valve fails open, or you spring a leak in the drier, and the truck tries to level itself it will only be able to lower, then further leveling makes it go even lower, until it's eventually all the way down.
I do not recommend driving it when it's lowered, you put extra stress on the lower control arm bushings when they're forced to twist that much, and aren't the most durable to begin with. There is also much more wear and tear that will occur without the dampening from the suspension, as far as the mechanical suspension, and drive train are concerned it basically turns a smooth road into a washboard.
In an emergency, yes, the truck will go, it'll be a rough ride, but it will get you somewhere if need be.