Volvo Owners Club Forum - View Single Post - Brakes: - Re-set brake fault valve & switch on 2 circuit 121

Charlie69Amazon · Aug 31st, 2022, 05:13

I'm finally getting back to working on the brake fault valve & switch.

A friend has a spare assembly wo we took it apart to see how it works. Very simple. However, as you all pointed out, it is now clear that the switch will definitley be damaged if one attempts to re-center the shuttle without removing the switch.

It is interesting to note that the shuttle valve is in two parts, two pistons, not one. I am not sure why.

I will install it with the switch facing up so I can see the valve inside. I can avoid modifying any of the brake lines by making a small bracket to install it with the mounting tab to the bottom instead of the top.

Also to avoid getting dirt into the switch I will make a small felt washer to cover the drain hole which will be facing up.

Thanks for your advice on this.

Aug 31st, 2022, 05:13	#8
Charlie69Amazon New Member Last Online: Aug 31st, 2022 05:13 Join Date: Jul 2022 Location: Calgary	I'm finally getting back to working on the brake fault valve & switch. A friend has a spare assembly wo we took it apart to see how it works. Very simple. However, as you all pointed out, it is now clear that the switch will definitley be damaged if one attempts to re-center the shuttle without removing the switch. It is interesting to note that the shuttle valve is in two parts, two pistons, not one. I am not sure why. I will install it with the switch facing up so I can see the valve inside. I can avoid modifying any of the brake lines by making a small bracket to install it with the mounting tab to the bottom instead of the top. Also to avoid getting dirt into the switch I will make a small felt washer to cover the drain hole which will be facing up. Thanks for your advice on this.