Longtime load proportioning valve/braking issues. Need recommended tech/shop/member to solve.

New move coming up to South Florida soon and it’s time to really get my longtime braking issues fixed for good. Since owning the truck, I’ve never been happy with the braking. The pedal has always felt mushy and with lots of air behind it. The trucks panic braking is in my opinion horrible and basically stops similar to a heavily loaded trailer pushing you without trailer brakes. The truck is non ABS, and in no scenario can I even come close to getting the wheels to lock up. The truck brakes, but never actually seems to create any real pressure.

I posted a long time ago when the truck was bought about the load proportioning valve and how the bracket for it was not extended when the truck was lifted. The original owner stated he did in fact use an extended bracket for awhile for the rod but never had what he felt was a good pedal and/or braking force while using it. He said he spoke with many Taco owners who were also unhappy with stock and lifted trucks and their brakes. The LPV rod that extends to the axle was finally just cut and not worried about. See my previous post if you would like pics.

After learning about the valve and how it works on these Tacos I did in fact tie up/pull up the rod coming from the LPV with a zip tie temporarily one day and found the truck to brake extremely good. Under hard braking at the first adjustment I made, I could lock up the wheels very easily. I know this is not safe/wanted, but it was nice to feel the truck finally make a hard brake like I think it should. I did not want to leave it this way so I removed said tie and have never addressed it completely.

Most auto shops have no experience with these LPV’s and seem to not understand what I’m talking about especially with the lift and the way it affects the truck etc. They tell me the pads and shoes etc. are all good and they have bled the brakes and that’s that.

I need to delete this LPV entirely and/or have some type of manual adjustment that I can set and forget, or replace the entire assembly and rod with new and include an extended bracket. My only concern with any of this is I find it odd that if the front brakes are doing all the heavy lifting due to me having so little pressure being applied to the rear shoes then why are my front pads in such great shape as well. It’s as if by not having this LPV working correctly or in the right position, the entire braking system isn’t getting correct pressures applied. Could it even be something else? The master cylinder was tested by a Toyota Tech in AZ a couple years ago and was found to be fine. Even he was dumbfounded. I find this so odd though because I’m far from a mechanic and I was able to get the brakes to lock hard and completely by simply using a zip tie. Even that though doesn’t seem to work anymore or at the last time I tried to recreate it.

Looking for reputable or recommended auto shops, off-road shops, and or private techs that specialize in Toyota trucks specifically with lifts and modifications. Currently located in central/Southeastern Ohio roughly 70 miles from Columbus. Willing to travel to the right person/and or shop that can take the time and get my truck braking and operating as it should. Thanks so much and sorry for this ridiculously long post.

 

1st hows your rear suspension? I ask this because I had issues with spongy brakes and no firm brake pedal before and I realize that every time my rear end bounces up and down that lpv arm is swinging up and down as well and throwing off the braking balance, or thats how I would say it. I've replaced the rear suspension after replacing the rear end with a locker and bled lpv and rear shoes and all was good afterwards.

Rear end suspension had leafs and shocks replaced as the oem ones were really worn down. The rear shocks wouldn't even uncompress after I compressed it with my hands.

 

The LSPV is a good idea on paper but not so much when put on trucks. That's why you don't see this kind of setup anymore

if you want to bypass the LSPV, connect the upper line (that's the INLET of the valve) coming from the front of the truck to the rubber line above the diff that goes to a splitter that then sends the fluid to both wheels. Then plug or remove the lower line of the valve (it comes from a splitter located in the driver's side wheel well). This line is just a return line and you don't need it anymore.

You can leave it like that or if you want, you can add a manually adjustable proportional valve by your master cylinder, on the line that goes to the rear wheels. This will replace the removed valve and act just like it, except it is manually adjustable

 

Rear suspension is good. Pretty much new Old Man Emu spring packs and shocks. LSPV is currently hooked in place but the rod that comes out of it that leads to your axle has been cut. I’d really like to just set it and forget it with something and get a good pedal and pressure and/or bypass it all together as posted above. I’m still wondering if this is the real issue though with my braking. I would have to assume it is because when I pulled the rod up and secured it a long time ago with the zip tie I had ridiculously good brakes. Too much pressure in fact and the tears were locking. I almost feel as if somehow the LSPV is not letting the front brakes grab as hard as well. I definitely want this fixed before I start to build the truck for camping/overland type activities.

 

You should fix the rod issue, I think thats the cheapest route.

 

You do use your parking Brake to keep the rear Shoes adjusted ??

When was the last time the Rubber Brake Hoses were replaced ??

The Rubber hoses tend to age when they do on application they swell up like a balloon

A Shop that does not understand the concept of the LSPV just looking at it just does not want to touch it

 

I vote to do away with the load proportional and put a manual control valve under the hood.

never liked mine either. I've set it perfect and 2 weeks later it's all out of wack again although mine seems to lock up too easy when they work at all. Never replaced rear shoes in 200K miles and they look new. Who knows what's up.

While it's true I don't use my emergency brake everytime and keep it all adjusted perfectly that's just the way it is. Brought up in flatland and don't use it (much)


The only way I can think of it to affect the front is if there is an internal leak inside yours. Mine's not much on locking up the fronts either unless in the wet. I do know I need new rubber hoses.

 

I keep about 50# of junk in the bed and run a fiberglass topper that’s pushing about 150# easy. Plus a full size 33” spare. I cut my rod and zip tied it up against the bed. Started low and did a few ‘braking’ tests to get it where it would lock up without my tool box but not with it unless some serious pressure was applied.

I wouldn’t mind a plug and play proportioning valve under hood or even in place of this rod valve. I’d rather not have fittings and stacked up to make one work.

 

Dealing with the older Toyota 4x4 Trucks most times the LSPV had quit working long before I saw the vehicle..

The first time brake fluid was out those valves were removed and lines plugged at the front some got manual valves some didn`t just a matter of getting used to driving

After all none of my early vehicles had a brake valve you just drove careful in the rain or snow with a empty truck

It could be as simple as Water in the brake fluid from old age

The brakes are a complete system if one part is not up to speed the whole system suffers