Mudders hate him! 1 weird trick to fix the LSPV (1 Viewer)

[excessive]

Now that you have fallen for my clickbait article, here is my LSPV delete write-up. Ever since I got my 80 series, I have wanted to improve the braking power, because, frankly it sucks. ( At least compared to other modern cars I have driven) One of the major things I wanted to do was get the LSPV working, back to factory specs at least.

At first I tried to fix and properly adjust my LSPV, I bought a spare good used one from a junkyard, took mine and the junkyard one apart, and used the best parts of both to make one good one. I put it back on my truck, adjusted it to factory specs using the service manual, bled multiple times using FSM procedure, and had almost zero improvement - after probably 10 hours worth of work.

At this point I did more reading, and ultimately decided to go the LSPV delete route. Several people have done this and noticed improved braking performance. I see most people use a brake line "T" fitting and bend the factory lines to fit, or custom make a small brake tube. This seemed like a lot of work, potential for leaks, non-reversible mod, etc. While I had my LSPV apart, I thought it might be possible to just reuse the LSPV housing and make no modifications to the vehicle's brake lines. I went to the hardware store and got a stainless bolt, washer, and nitrile o-ring. I did some research about nitrile and brake fluid, apparently the two ARE compatible.

I then took all the guts out of the LSPV, and fashioned my "plug" to reuse the body of the LSPV as the brake line T. I then deleted the LSPV arm and other nonsense. Bled the system again using the FSM procedure. The idea seemed to work ! I have been testing this for about 2 months now, and so far , no leaks. I can also say that I have improved rear brake performance. With ABS disabled, I can lock up the rear brakes, which I could never do before. So in conclusion, I would like fellow mudders to see if they have any opinions as to why this might be a bad idea. For the time being , I plan to keep it the way it is.

 

[excessive]

more pics.

 

[thatcabledude]

Nice!

I love the title too.

 

[excessive]

and what it looks like installed.

 

[b16]

Nice, however you never want to be able to lock the rears before the fronts lock.

Might be a good idea to throw a manual prop valve for rear proportioning.

 

[LandCruiserPhil]

Nice, however you never want to be able to lock the rears before the fronts lock.

Might be a good idea to throw a manual prop valve for rear proportioning.

I Have been running that way for years and with my set up no proportioning valve was needed.

 

[b16]

I Have been running that way for years and with my set up no proportioning valve was needed.

Guess it is the ex-road racer in me. Locking up the rear before the front is usually a scary event, causes the rear to come around on you.

 

[tacosupreme]

Guess it is the ex-road racer in me. Locking up the rear before the front is usually a scary event, causes the rear to come around on you.

I don't know if it's the AWD or what, but they all lock at the same time, even on ice. I don't have ABS on mine either.

 

[hammerheadfistpunch]

now sell me a completed plug so I don't have to track down all the parts. or at least a list of the parts. So sick of that thing.

 

[NLXTACY]

now sell me a completed plug so I don't have to track down all the parts. or at least a list of the parts. So sick of that thing.

Hey! I've built a business doing exactly that

 

[b16]

Question, if you do this do you still need to bleed the LSPV? or is it really just a big T fitting now?

 

[Beej]

Someone tell him its a bad idea so I dont have to add this mod to my list.

 

[IdahoDoug]

Hmmmm. That factory load sensing proportioning valve adjusts the brake power to the rear wheels based upon the traction they have. It does this by INCREASING the brake power to the rears when the suspension is compressed, and DECREASING the power when its empty. By eliminating it (vs having an operating LSPV), your fronts will tend to lock up at max braking when loaded, and the rears will tend to lock up when unloaded. In normal driving and some gravel road testing you may declare victory with this mod. The first inkling it was a bad idea will be when you are doing an emergency evasive maneuver to avoid something for real, and the rear end comes around. If you're really, REALLY good you will catch it and merely end up in the oncoming lane yelling 4 letter words and heading back to your lane. And if you're really, really LUCKY you will not center punch 3 teenage girls in a Nissan Sentra and kill them all. If that happens, and during the modern forensic examination of your vehicle that happens nowadays they discover you eliminated a device meant to help in emergency braking maneuvers, you will get shelled. And deserve it.

I get it. The LSPV broke and the first try did not fix it. But that's not a good idea and shouldn't be sold as one on a public forum. I have personally driven vehicles on proving grounds during brake system development and there is a damn good reason for that feature on a high CG vehicle.

Doug

 

[richardlillard1]

And just like clickbait, it didn't have an actual fix like the headline suggested.

A+, 5/7, would get duped again.

 

[excessive]

Thanks for the advice everyone. Doug - I think you've sufficiently scared me to at least add a manual proportioning Valve to the setup, I will continue testing.

I want to reiterate that I am not suggesting anyone do this , I mainly wanted to get opinions on whether the experienced folks here think this is a good / bad idea - so thank you all for the comments .

 

[Comet]

Someone tell him its a bad idea so I dont have to add this mod to my list.

@IdahoDoug to the rescue. I have done the LSPV and ABS delete. The braking is better; however, Doug points out a very valid point. The a$$ end of a 6,000 lb vehicle getting away from you will have devastating consequences. @LandCruiserPhil also brings up a valid point regarding his set up with no need for a proportioning valve.

I run an ARB and winch up front and the stock bumper in the back (Lusting after a Luke's 4x4 rear) and when there's nothing in the back of the rig I can manage to lock up the rear right before the before the front locks. When I am fully loaded for a long weekend, everything works flawlessly.

The brake system has four cylinders in the front caliper and two in the rear. Seems like the 70/30 split for proportional braking would be addressed by default. Load does seem to have an impact on the braking performance in my rig.

I am not suggesting anything for anyone to try, this is just my experience and should be taken as such. There, my lawyers are happy I attempted to cover my .

 

[LandCruiserPhil]

Hmmmm. That factory load sensing proportioning valve adjusts the brake power to the rear wheels based upon the traction they have. It does this by INCREASING the brake power to the rears when the suspension is compressed, and DECREASING the power when its empty. By eliminating it (vs having an operating LSPV), your fronts will tend to lock up at max braking when loaded, and the rears will tend to lock up when unloaded. In normal driving and some gravel road testing you may declare victory with this mod. The first inkling it was a bad idea will be when you are doing an emergency evasive maneuver to avoid something for real, and the rear end comes around. If you're really, REALLY good you will catch it and merely end up in the oncoming lane yelling 4 letter words and heading back to your lane. And if you're really, really LUCKY you will not center punch 3 teenage girls in a Nissan Sentra and kill them all. If that happens, and during the modern forensic examination of your vehicle that happens nowadays they discover you eliminated a device meant to help in emergency braking maneuvers, you will get shelled. And deserve it.

I get it. The LSPV broke and the first try did not fix it. But that's not a good idea and shouldn't be sold as one on a public forum. I have personally driven vehicles on proving grounds during brake system development and there is a damn good reason for that feature on a high CG vehicle.

Doug

I think the real problem is being overlooked. I would guess 90% of the lifted 80s have a LSPV that is not adjusted properly making the overall breaking much more dangerous than driving without a working LSPV. How many people, vendors, or dealership properly pressure adjust and test the correct adjustment of the LSPV? The proper adjustment is rarely talked about anywhere. All you hear when you lift your 80 is just add this, bend the rod like this, or raise the LSPV this much and you will be fine. Guess what these method do not correctly address the proper adjustment of the LSPV. Does a LSPV even have the capabilities to work properly with the increased travel on a lot of our 80.

Im all about safety but I dont see a non or not properly working LSPV safer than without any input from the LSPV and full bias to the rear. When people talk about the possibility of the rear brakes with a early lock up is that not the ABS system job?

For me I dont have ABS or a functioning LSPV and Im 100% comfortable with high speed lock up having done it more than once.

Also the 100 series does not use a LSPV or any way of adjusting front to rear braking with a load change that Im aware of.

 

[Funner]

I think the real problem is being overlooked. I would guess 90% of the lifted 80s have a LSPV that is not adjusted properly making the overall breaking much more dangerous than driving without a working LSPV. How many people, vendors, or dealership properly pressure adjust and test the correct adjustment of the LSPV? The proper adjustment is rarely talked about anywhere. All you hear when you lift your 80 is just add this, bend the rod like this, or raise the LSPV this much and you will be fine. Guess what these method do not correctly address the proper adjustment of the LSPV. Does a LSPV even have the capabilities to work properly with the increased travel on a lot of our 80.

Im all about safety but I dont see a non or not properly working LSPV safer than without any input from the LSPV and full bias to the rear. When people talk about the possibility of the rear brakes with a early lock up is that not the ABS system job?

For me I dont have ABS or a functioning LSPV and Im 100% comfortable with high speed lock up having done it more than once.

Also the 100 series does not use a LSPV or any way of adjusting front to rear braking with a load change that Im aware of.

These are good points. With all the changes to my truck I wonder if anything is working the way it was engineered as a stock vehicle. I assumed that whatever I could do to improve how it stopped in its current configuration was the right thing to do. I really don't know what else I could do as I don't have the knowledge or tools to properly test and reset everything. New brakes pads, rotors, calipers all good, raised the lspv a bit.

 

[hammerheadfistpunch]

Hey! I've built a business doing exactly that

I was on the site going virtually poor just the other day

 

[NLXTACY]

I was on the site going virtually poor just the other day

You and thousands of others. I'm virtually rich!