I was rippin out the rear diff on my 2nd Gen 4 door when I noticed that a previous owner had wired up the LSPV and that the lines to it were cut up front! I never noticed any braking probs, so I was wondering if anyone has ever just bypassed this and sent the fluid straight to the rear drums? I'll be running 31's. so I'd be impressed if they ever locked up. Yeah, I've search and learned what they do. 

I have the arm on the LSPV pulled down tightly with the spring and have it attached to the frame so that the LSPV is bypassed/turned off(just like hauling alot of weight). Remember that bypassing this valve does NOT bypass the proportioning valve up front, you are still getting proportional braking force front and rear.

On the trail with the rear suspension droopped down there is very little braking power to the rear brakes, I would prefer having full braking all the time.

One thing to be aware of is that having the LSPV set to allow full rear braking puts the master cylinder at near max capacity and wouldnt hurt to be upgraded, especially if you do a 4dr brake upgrade to a 2dr.

I see better braking modulation(though requires more pedal effort as mentioned above), I have not had the rear brakes lock up under heavy emergency type braking at all,  that could be a side affect of the wheelbase stretch of my lift kit and that fact I run 200lbs of sand in the rear(untill the new steel bumper and fullsize spare are mounted).

Upon further investigation it seems that the rear brake lines, both to and from the LSPV rotted out. Another line was grafted in to supply pressure to the LSPV which was wired up I presume in the wide open position. The return line was pinched off and the master cylinder has a cap on the return line location (driver's side front). I have pristine parts I could get off a donor vehicle, but I'm wondering if I should even bother? Thanx for the reply. Any other opinions? This rig will have 16" springs in the rear and a 2" BL.

Two things ...

 - talonxracer - there's no proportioning valve up up front - just the one at the back.

 - dustybadlands - there's no "return" line in that brake system - the fluid flows in one direction when you depress the pedal and in the opposite direction through the same line when you release it.  I don't know what line your vehicle has capped off on the driver's side front, but I think you need to sit down and have a look at how that thing is plumbed, brake systems are something that really should not be modified, unless the person doing it has a clear understanding of what they are up to.

Here's a quick synopsis pf the brake plumbing on a Trackick without RWAL.

The master cylinder has two sections, front brake circuit & rear brake circuit ...

 - the front brake circuit section of the master cylinder has two outlets, one feeds the driver's side wheel directly, the other goes to a one section of a 5 way joint - the 5 way joint is actually two separate sections, a 3 way section & a 2 way section - the front brake circuit goes to the 3 way section of the joint, and through it to the passenger front wheel, and to the LSPV - the purpose of this connection is to provide the LSPV with a pressure reference.  The LSPV uses this pressure reference along with the pressure exerted by the "load sensing arm" to determine how much pressure from the rear wheel circuit should be allowed through to the rear wheel cylinders.

 - the rear brake section of the master cylinder has a single outlet which goes to the 2 way section of the 5 way joint and through it to the LSPV, through the LSPV to one rear wheel cylinder and through that rear wheel cylinder to the other one.

Is it just 2000 Tracker LSPV's that don't have a return line , or all LSPV's? My front brake section of the Master Cylinder has 3 outlets (or 2 outlets and one return). Sorry, I assumed that the return line reroutes excessive line pressure back into the front brake-lines like Toyota trucks. A plumbing schematic would be helpful, anybody?

I've never seen a brake master cylinder with a "return" line - as I mentioned before when you step on the pedal the fluid goes out the line(s) and when you release the pedal it flows back through the same line.

The description I provided earlier is for a first generation Trackick without RWAL, second generation is similar in concept & function (unless they have ABS), but slightly different in the plumbing - there is no 5-way block on the second gen, so the master cylinder's three outlets feed the driver's side front, passenger side front and LSPV reference port.

I've attached a diagram for a Vitara/Grand Vitara, the 2000 Trackers should be the same.