OK so first thought is you have just introduced one more failure point. Second thought is it sure would have been nice on some of our 1 hour and more descents in south America.
Good point, the shuttle valve is the only real failure point, and it is easy to bypass on go back, as I used the push-fit fittings. The one I have from a Unimog U2450 - designed to do the same thing on that truck, so should be reliable.
An alternative view is that it adds some redundancy, if the foot switch was to fail, then I would have no exhaust brake, this way I have a redundant method.
Every toy or gadget adds a failure point, but as long as there is an easy way to bypass it, no big deal.
I have a lot of redundancy built into the truck. I have dual alternators, and can start the truck from the dedicated starter battery or from the house batteries, both completely independent, unless I push a button to connect the two alternator and batteries in parallel, or disconnect either. I have dual air compressors, one mechanical the other a pair of electric ones, so I can charge the air system up without the engine running.
Each of those does add an extra thing to fail, but also a back-up if one does fail.
I only carry one spare wheel, but have an extensive array of tyre repair patches including some really big radial patches and a TPMS to warm me before they get shredded. I carry a lot of spares, the things that could stop the truck from going mainly. I carry complete set of hoses for everything, fuel lines , joiners and clamps. Alsot hings like clutch slave and master cylinders, brake treadle valve, univeral joints, seal kits for brakes, spare hard brake line, brake hoses, starter solenoids and brushes, alternator regulators, water pump seals, injectors, thermostats, I even have a complete gasket set for the engine under the bed
Having built the truck, I can say quite confidently there is not much I can't repair, and I carry all the tools need to do these repairs.
If we were heading out on our around the world trip, I'd have a spare overhauled portal box in the truck as well, but right now I just have a couple packaged up and ready to post. I have things like spare CV joints, half shafts, brake calipers, water pumps, a crown wheel and pinion for my diff ratio, and various other rare or discontinued things, all packaged and labelled so that they can be posted out if we need them.
If all else fails, we have a Sat phone, and EPIRB/PLB, and a Garmin InReach as well.
