I bet you guys are smarter than me, and can see my current predicament long before I did.

Here's the engine bay before starting in on this, excuse the mess:



As I have plenty of friends, I'm in the process of doing the "power bypass" hack to rid myself of the three amigos. So I loosened the Wabco controller without removing the brake lines, cut the giant zip tie off (!) and discovered only two screws holding the shuttle valve in place. Being ever the optimist, I think "it's OK, they lost one, whoever was in there before".

("If they were in there before, why do I still have amigos?" would have been a question to ask myself, even if unanswerable.)

Anyway, I get the valve off; its switches pass the resistance test. As it's likely the problem is the common "bad circuit board" fault, I perform all of the necessary hackery to send power straight to the valve:




So far so good. I found an appropriate replacement screw, in my collection of appropriate replacement screws, went to put the valve back on, and discovered that a screw would not go back where one was missing. My heart shrunk ten sizes in that moment, and if some former mechanic (or owner) is wondering why they have a splitting headache at the moment, it's from the hexes I put on them, and I don't even speak hex.

So out came the whole bloody box, and here is what I found:




It's a bit hard to see in this cruddy photo, but that is a broken off "easy out". You can see the flutes on it, when looking via a glass; they're shallow and left-handed, hence my conclusion it's an easy-out. I do not have any bits hard enough to tackle carbide, nor do I trust myself to not break such a small, hard bit, even if I had one.

To vent, WTF. It's a small screw holding a plastic part, secured with a bit of blue loctite. Not sure how it breaks in the first place, but I would have thought the remnants would have come out with careful use of a "plain jane" HSS left-handed bit. Using an easy-out on something this small is a sign of madness--the one broken off in here is larger in diameter than the original screw!

Sigh. So now I have to pay a visit to the machine shop, or maybe see if I have a giant zip tie. Man, I hate shade-tree stuff (says the shade-tree mechanic).

 

Just find a used Wabco ABS Pump. I imagine they are plentiful and cheap. Maybe a pick a part will have one near you.

 

If I buy a used pump in order to just get the body, assuming no broken off fasteners in the used pump, is the main body subject to wear, if I swapped over all my known working parts to the new used assembly? I guess I'm asking how likely a used one is to be a dog.

 

I had that bolt snap off too. Thing is, that ABS unit is a giant chunk of metal, and you don't have to hold the switch on that firmly, as it's not holding against brake pressure. I just drilled a hole next to it and put a machine screw in.

 

It could be because the shuttle valve switch circuit fault wasn't the problem. Did you have the ABS codes read? The Three Amigos can also be triggered by problems with any of the four wheel speed sensors (or more likely their connectors) or by something else. Unless the ABS codes are read trying a fix is just a guess.

 

Likely it will either be fine or just need the same rebuild you are doing. In and of itself, the pump is not a complex part, the fault is the leaky seals that damage the electronics.

Falconwerks in AZ sells, or at least did sell, a seal and shuttle valve kit.