What's this?

Looks like something related to brake lines but what exactly does it do? The line going down to the axle just stops there... Like it doesn't seem to go anywhere? It just pivots if needed?

 

LSPV, load sensing prop valve, auto-adjusting using the linkage you see there based on how much load is in the rear.

Can lead to shitty braking if not adjusted correctly. Can lead to shitty braking if you don't bleed it in valid order, especially in cases where you KNOW there is air in the lines.

they do fail periodically. There is a test you can do to check., I can find the video on YT if you can't.

 

Load sensing proportioning valve. If the truck doesn't have abs.

 

It’s a load sense/proportioning valve. The weight of the bed determines how much force is applied to the rear brake pads when braking. That pivoting joint is instrumental to it working correctly.

 

I have ABS. I have LSPV.

 

Me too.

 

Oh interesting! Never seen that before. I'll try to find the video your talking about @shifty` , but if you know exactly which one, a link would be appreciated

 

Not the best quality but the guy does a LOT of 1st gen stuff. I don’t always agree with him but I think it’s worth a watch:

https://m.youtube.com/watch?v=kZoLH-7jMfA

 

Perfect just watched it, yea that's decent I definitely get it now! I'll have to put the truck on jack stands in the rear and check

 

That and the e-brake system are both important to keep functional and properly adjusted.

To that point, you're in the area that's most critical for proper overall braking on these trucks. Tuning the rear is so important there's an entire sticky thread on the topic: https://www.tundras.com/threads/rear-brake-adjustment-theory-and-practice.99575/