Ilovemountains

Hi, I have yet another question! What purpose does the rear proportioning valve serve. Does it sense when the rear end is sagged and allow the rear brakes to actually work. The reason I am asking is, I recently installed Downey lift springs, and they came with a bracket that raises the one end of the assembly up to compensate for the lift “the axle side”. My rear brakes are now working better than before, I can really tell when its raining and I fist use them, I have had the rear wheel actually skid which never happened before this is not a good thing but it proves my point!, and my dry road braking power has dramatically increased. I didn’t do any thing but move the one end up onto their bracket. I guess what I am trying to say is if there is an adjustment that you can do to your proportioning valve that makes the rear drums actually apply stopping power to your rig I would do it! I could be wrong though and may need to adjust mine that is why I thought I would post this for your opinions! I have tested my theory on the dry roads and have almost locked my front wheels and the rears didn’t skid I am not going to intentionally skid my Revos into flat spots but I do think this may be worth looking into. Any more braking power you can squeeze out of your rig the better in my book! Matt

Phisherman

Can somebody post a pic of the LPS, with a nice circle around the part needs to be moved up? I've needed to do this for a few years...

2wd1stgen

Some one correct me if I am wrong but I think the rear brakes need to be adjusted not the LSPV. The rear brakes go out of adjustment often.

2wd1stgen

I do not think a 2000 4runner has a LSPV but if it does it is above the rear axle with brake lines going to and from it.

Robinhood150

You generally don't want the rear to lock up first, the truck tends to want to swap ends. This is the reason some of the 2nd gens have rear only abs. Does the downey bracket have more than 1 set of holes? If so, then you might have used the wrong set, that is, the bar is too high for the amount of lift.

I believe the 2000 has 4 wheel abs and does not have a LSVP.

Victor

There are 2 holes on that bracket. The lower one is for springs only and the higher one is for the Downey springs and 1.5" spacers. You probably hooked your LSPV to the top hole instead of the lower one and now they are too sensitive.

Ilovemountains

No I installed it on the lower holes, the rear wheels dont lock before the front, only when the truck has sat for a few days and the roads are wet, I guess the insides of the drums have a layer of rust making them grab more, but they never did that before. The brakes feel a lot better with it in its current position. You do have to keep drum brakes adjusted, there is a star looking adjuster that you turn from the back side of the drum with either a special drum brake tool or a flat screw driver. I recently replaced my stock rear brakes at over 135,000 miles! Not bad huh.

MvCrash

Rear Auto adjusters should also adjust by backing up and pumping the brakes.

MV

Phisherman

Most 2000s have ABS. It was one of several options that I didn't get.

Post #4 on this link, disregard the green drawings and look to the right of them...

In this pic you can see the spring is completely unsprung. On my 4Runner, the left side is a lot higher than this and the spring is sprung more. The right side attaches to a bracket with a built-in adjustment slot. If I moved the right side higher to get the spring compressed again, would this be the solution?

Robinhood150

That's exactly when you don't want the rears to lock up.

Phish, your pic isn't working.

Phisherman

pic fixed...

you can see the adjustment slot on the left side of the spare tire

4Hummer

Phisherman

It's in post #11. The LSPV is apprently different in 2nd and 3rd Gens.

2wd1stgen

"Rear Auto adjusters should also adjust by backing up and pumping the brakes."

Does only the 4 wheel drive have the auto adjuster or does the 2wd also have it?

superjoe83

they both have it, in fact Ive never seen a newer car without one, and some drum brake setups adjust when backing up and some adjust when the parking brake is pulled, thats how my taco is set up

2wd1stgen

thanks. I tried it and it seemed to work great. I can really feel the rear brakes braking now not just the front like before. i just hope I did not over do by speeding in reverse and slaming on the brakes skidding to a halt several times

NCSU-4runner

im at work right now, this is the only pic i have of a 2nd Gen LSPV. This view would be from the middle of the truck looking towards the back, if it were still on the truck. I took mine out altogether and am going to put a permanent adjustable one on. With ~ 6 inches of lift and rear discs it was worthless to keep this anyway. The bar exiting the piece at the bottom right is the level gauge, the other end of this is what needs to be raised when you lift the truck. The idea is to keep it level at steady state.

MvCrash

I would have to disagree with the valve being useless. The ony thing to consider is that the extreme weight differences that can occur when you place weight into the bed or rear cargo area. That valve accounts for the weight and adjusts the braking accordingly. If not, the braking on the vehicle would not function properly. If one never places weight in the cargo area, I would suppose removal of the valve may be ok. In my opinion this would be a mistake unless the front proportioning valve was adjusted accordingly.

my Nickles worth

MV

NCSU-4runner

for a near stock setup that might be true, but for a very large lift and non-stock braking setup ( i have rear disc brakes ) that valve is going to be completely out of calibration to adjust. Using a permanent valve with a constant proportion of rear brake bias seems like a much better option for ME, maybe not everyone. I never plan on towing anything anyway.

MvCrash

I would agree with you on the non-stock config. My question is really simple: In a non stock config how do you know what bias to use on the brakes. I'm certain that it takes more than a good guess and making a wrong decision can have really bad outcome.
be careful!!!

MV