I have an 1989 Toyota truck, 4x4 , 22RE Engine and have recently redone the back/drum brakes.

Now I'm finding that the LSPV seems stuck in the closed position. Providing full braking power to the front and nothing to the rear.

In the process of bleeding all the brake lines I was unable to get any
fluid through to the back brakes. I started troubleshooting the problem
at the master cylinder. I bled it then move to the disk brakes (front)
then back to the rear/ drum brakes. Getting no fluid in either brake at
the bleeder valve I traced the line back to the bleeder valve in the
LSPV. Plenty of flow to that point and nothing after it.

So now what? Adjust, repair, replace. I'm open to any options but my
Hames service manual say go to the pros. Id rather not if its something
I can do.

Ideally I'd like to find a desription of how to test and troubleshoot this and or a repair and replace procedure.

Parts prices run $150.00 for the valve and $75.00 for the spring.

Any and all advice appreciated...

Brett

 

i think that part of valve's linkage is adjustable -- maybe give that a try? sounds like if that's the problem, it's adjusted too far out so the valve thinks there is no load on the back end, and is putting 100% of braking force to the front.

 

I've found something curious here in working on it a bit more. THE LSPV has a bleeder valve on the back end...and what looks like room for another one in the top near the output brakeline running to the drum brakes. However mine is missing that bleeder. Like its fallen out long ago. I'm going to try and get a diagram of this thing to look at. If anyone know where one might be online Id appreciate it.

Brett

 

You got a fax number? I can send you the toyota blow up of it
mike

send me an email, I might be able to email it to you as well
mvankeuren at parkplacetexas dot com

btw it only shows one bleeder valve

 

This is what mine looks like. (Ignore the wet look.)

 

What exactly do you have to adjust? I'm currently having the same problem on my 1987 pickup.

 

I have the exact same problem also.....

You adjust the long bar that runs from the LSPV to the rear axle housing.

Not sure what is going on with mine. I think I need a new one but am searching for a way to fix it instead b/c they are pricey!!

 

http://www.ncttora.com/fsm/index.html

This is toyota factory service manual online and downloadable... shows how to adjust the lsp and bv.

hope this helps

 

I just took the hunk of trash that was left of my LSPV off on the weekend, it'd been bypassed by the PO with a manually adjustable bias valve and what was left of it was a rusted mass of something and old brake fluid. I'd suggest dealing with LSPV issues by removing it and going that route, you can even put the manual valve in the cab for on the go adjustments! Infinitely cheaper too!

 

I guess I have decided to go with the Wilwood unti. To bad I need the dual inlet one, it cost more

 

After a long phone conversation with the tech support guy at Wilwood, I ordered a single inlet / single outlet proporsioning valve. I guess I am going to eliminate one of the lines. I thought I needed a dual inlet but from what I understand one of the lines runs from the front of the truck to the back, thru the proporsioning valve & back to the front. The one that runs back to the fron is going to get plugged & eliminated. Does this sound right to anybody?? How have others done it??

 

ok so the line runs from the M/C and into the LSPV unit, from there it goes down to the T on the differential and splits to each drum. The single unit would be fine for this application.

 

the front brake line comes out of the m/c then under the m/c it tees off one to the d/side and one to the p/ side and tees off again one line to the caliper and one to the lspv along with the rear brake line, with one line coming out and going to the rear brakes. The way I understand it works is the valve adjusts how much if any additional pressure is taken from the front brake line, to increase or decrease pressure to the rear brakes. With no additional pressure coming from the front, this would put the rear brakes at least amount of pressure, thus resulting in poor braking. It dosen't sound like a single inlet/ outlet would produce enough pressure to give the truck a good braking balance between front and rear. I am having the same problem with my 86 runner and will be going with a duel to single bias valve to add pressure to the rear lines. this seems to be a common problem with these systems.we all need a good challenge from time to time!

 

Does anyone know where to get a new LSPV?

 

Get a manual bias valve instead, mount it in the cab, will save you a lot of time and money, especially money. If you -really- want to replace the LSPV, junkyard for doing it on the cheap, or dealership/online for new, be prepared to sell off some organs if you want new replacements.

 

Anyone know where I can buy a proportioning valve? Im just gonna replace it. Would like to find a used one....

 

Try a local pic n pull or wrecking yard, If you can`t find one there google yota yard, there in Denver and they should have one. Ive ordered things from them before and there service was good.

 

I have 2001 tacoma with the same problem with the load sensing proportioning and by-pass valve being stuck. When changing brake fluid I could not get any fluid to back brakes. I filled up the master cylinder and bled the front brakes anyway and had a solid brake pedal and front brakes. Then after knocking on the valve some, I was able to get brake fluid to the back brakes, but then the brake pedal went all the way to the floor due to a great amount of air in the back brakes. I bled the back brakes and then immediately took the truck to a toyota dealer. I feel this could possibly be a safety issue if it is possible for a valve that is stuck for a long time to become unstuck while driving on the road. I took the valve apart and found that it still binded even after I cleaned it up. There was not much dirt in the valve, but the valve still seemed to lock up on the o-rings and other rubber parts inside the valve. My opinion on this is to go get it fixed as soon as possible. It cost me about $400 at a dealer to have it replaced (and they also have the equipment to test it) but that is better than taking a chance of having no brakes on the road.

 

why didn't you just replace it? $400 charge from the dealer! Ouch! It costs much less for the part. You had the bad one out already. The dealers charge much more than Napa, Car Quest or Autozone would! I got ripped off badly by the dealer I bought mt Toyo 4x4 from. He got red faced and started taking items off my bill when I examined the parts he took off and replaced. Water pump was still perfect, hoses were flexible and not dry rotted or cracked as he said, fan belts were supple and fine (no wear or cracks)! He thought the owner was a woman and tried to take advantage of her (truck purchased in my wifes name). Contacted Toyo Corporate Headquarters in Calif. He was severely criticized by them! We never went back there again! Never ever trust a dealer again! Thieves and liars! I am being kind!

 

Actually I believe the part itself was about $200 at the dealer and I think this is a Toyota part. Check out the fuel lines that connect to the fuel filter and see how much they cost if also you want to get shocked. Actually I took the valve apart completely after the dealer changed it. After I did a little research I found that it takes special equipment to check the operation of the valve after it is installed, and I did not have the equipment. I possibly could have gotten this done cheaper at another shop other than a Toyota dealer, but at that time I was fed up with the entire situation and just decided to go with the dealer since they had to order the Toyota part anyway. The main reason I posted my original message is because I think this is a potential safety hazard, and possibly there are a lot of trucks running around with bad valves and the owners may not even be aware of it.