Codes reader says I have a shuttle valve fault. Let’s say I do narrow the problem down to the shuttle valve assembly and I install a new unit. The Option B is preformed to keep the new shuttle valve internal wiring from suffering the same fate as the original unit, correct?

Just asking for clarification because if the new shuttle valve lasts half as long as the original I really would rather avoid spicing into the loom. The Option B directions look simple enough and there is one listing on eBay from the U.K. for a prefabed Option B shuttle valve but again I’d rather not cut into the loom.

anyone with experience?

 

The cut is trivial and free and you can wrap electrical tape around it that is superior to the factory wiring insulation.

The entire Option B job took me 30 minutes outside in the dark. Stop overthinking or overpaying for parts. Do the real fix... the free fix. It absolutely works.

 

Thanks for being of absolutely ZERO help.

 

This is my understanding of the option B:

”The Option B is preformed to keep the new shuttle valve internal wiring from suffering the same fate as the original unit, correct?”

That’s the question.

 

That is correct, sort of. What No Doubt is trying it say is that there's a good chance that buying a new shuttle valve is overkill. The problem you have is more likely to be failed insulation on the wiring from the contacts to the valves themselves, and the Option B fix will correct the problem. Trying to prevent a problem that does not yet exist is a little hit or miss since you can't be sure exactly where the insulation will fail. You can certainly glob the whole area with liquid electrical tape or similar, but applying the actual Option B fix, which in my case was some electrical tape over an inch or so of exposed wire, will be difficult to execute since taping the entire length of wires could present an interference problem in such a tight area. Either way, you should disassemble the unit first to assess the problem. I'm not so sure a 1/2 hour in the dark is accurate expectation for everyone, especially on your first go, but it's actually an extremely simple job once you wrap your head around what you have to do. Unbolt the WABCO, lift it for access to the 3 bolts, remove them to R&R the valve unit. It's that 1/4" high black plastic plate on the bottom of the WABCO.

If you want to make the job a little easier, cut about 3/8" off a 4mm allen key and stuck the stub in a 4mm socket so you can use a ratchet to undo the three bolts holding the shuttle valve assembly to the WABCO unit. There is threadlocker on the bolts and using a right angle allen key to remove them is considerably more difficult. You can see I propped my WABCO unit up using a large bolt as well. You have to carefully bend the brake lines to accommodate that much space but it's not destructive if done right.

 

Got it. I’ve got a new shuttle valve. I’ve got a new shuttle valve modulator switch ready to drop in, it cost less than a tank of gas.Thanks again for answering.

 

Frank,

First, the code is for the shuttle valve switches, not the shuttle valves themselves. Option B bypasses a failed solder joint or joints on the shuttle valve switch connector. Sometimes the shuttle valve seals fail and need to be replaced, but unless you find evidence of brake fluid on the switches in your truck that's not necessary.

Josh Salas's original Option B writeup is linked below. He walks through how he analyzed the problem and how he first tried to address it (Option A). It can be a somewhat tortuous read, so if you want to you can search for "Option B" within the writeup and start there.

You very likely won't need to replace the shuttle valve switches. I tested the switches in my truck when I did Option B and they were fine so I just did the bypass. The shuttle valve switch test procedure is described in Josh's writeup. That was 64,000 miles and nearly nine years ago.

I hope this helps you. Good luck.

https://landroverclubvi.weebly.com/abs-mod.html

 

Ditto: also took me about 30 minutes and no more 3 amigos, Just do it!

 

Internal connector being bypassed inside the wabco unit is the main benefit from Option B.

 

X2 on the advice to rig up a hex key in a socket wrench, my job took considerably longer than the claimed 30 minutes solely because it took me a while to figure that out and those hex bolts were in there so darn tight.