Pros/Cons of an ABD/LSPV delete

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Joined
Dec 3, 2025
Threads
4
Messages
9
Location
Missouri
Hello all,

I've been tackling a soft brake pedal issue (just like the rest of us) in my 1995 80. I'd like to go ahead and do some restoration of the brake system before I subject myself to endless brake bleeding. I've installed NAPA reman calipers all the way around, and I have an advics master cylinder (I have a sinking pedal) as well as slee soft brake lines from cruiser teq on the way.

It seems like most people dealing with similar issues end up having to do an ABS/LSPV delete before anything changes. I would like to keep both if possible, but then again I'm not the most educated on the impact that having ABS really makes. So my question is this:

Is it possible to acheive a firm brake pedal without deleting the ABS or LSPV (part replacement or rebuild perhaps)? What are the pros and cons of removing these systems? How big of a step backwards would I be taking safety-wise?
 
Yes but can be a PITA which is why many just delete it.

The problem is effectively bleeding both. The ABS has a bunch of valves and chambers that trap air that requires a bit of effort to bleed without the SST.

You need to activate ABS to move air out of the chambers.

The LSPV can be sensitive and needs adjusted otherwise can also trap air.

It’s easier to just delete and send full hydraulic force to the rear.

I removed both and drove without for a while but I don’t like the imbalanced brake bias and modulating my foot on ice a million times is annoying on mountain passes.

I put the ABS back and added a manual proportioning valve for the rear.
 
It really hard to say. If you’re older and learn to drive without ABS keep a safe distance behind the next driver then not that big of a deal.
If your used to such safety nets and tailgate like most of the younger drivers I see you might need them more.

I also think that the ABS in these trucks were some of the first ABS systems and maybe not be the best and getting old and don’t work as intended.

I don’t think you’re going to get a cut and dry answer to much liability involved
 
Are there any negatives to using a manual proportioning valve as opposed to a factory solution? And is it a tedious job?
The LSPV adjusted flow based on ride height. So when the suspension squatted under weight it opened for more rear brake bias, or something along those lines.

The manual valve is mostly just set and forget. You could set markings to adjust on your own when loaded and unloaded but don’t need to. Lots of folks are running manual valves.

There’s some setup time to dial in the brake bias.
 
Diagnose the cause of the soft pedal. The LSPV is a adjustable proportioning valve. If its original its bad now. They dont last forever. They are not expensive to replace. Its unlikely your booster is good as well if original. I believe marks 4wd has upgraded boosters. A soft brake pedal can be caused by many possibilities. Blocking off parts of the brake circuits can help you pinpoint the cause. I would do that before deleting anything. One of 6 soft brake hoses could be bad, or a stuck sliding pin, or something else. The rear calipers have a sliding pin design that can get gummed up fairly easily even when new. Hope you get it figured out!
 
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just adding my .02. had the same issues going on. Deleted ABS which really didn't work anyways with 37's. Then a new Proportioning Valve was the ticket. all these years I've been running around and using my front brakes almost exclusively.
Its a whole different rig now.
 
Unplug your ABS see if your soft pedal goes away. If it does you have air in it and need to bleed the abs. A nice dirt or gravel road can solve that .. Go out and lock up your brakes a few times and let it skid that will force the air out of the ABS then you can bleed the brakes to remove it . If not you have a problem somewhere else, More than likely LSPV. I remove 90% of them and do not use a aftermarket p valve. A few reasons where I don't recommend removing it . Your in the mountains on snow and ice In that case I use an after market P valve to replace the crappy LSPV and set it using pressure gauges I have that screw into the bleeders. Or your on stock tires You will experience lock up if you brake real hard. Both are easily worked around by just getting used to it. As primitive as the ABS brakes are on these rigs they are a major plus for those in the mountains during the winter. Other than that they pretty much suck .. Lots of opinions on this topic with neither wrong. Hard to disagree with anyone wanting to repair it the Toyota way.. My rig hasn't had a LSPV for years. Not due to going bad But because I do pretty hard core off roading and hate having no brakes when the ass is light going down a steep hill
 
Can you tell us more about this process?

What are you looking for with gauges?
Equal pressure FR-RR? Something different?
Im looking for front to rear pressure. The LSPV makes the % spilt between frt and rear different between low , mid. and hard braking pressure, . I have found the mid range of 100% frt 60 to 70% rear seems to work well. I start at 65% Then adjust from there depending on the rig ..In winter might even drop the rear down to 50% if we have alot of ice . Keeping in mind I have a stiffer lift on 35s.
 
LSPV will only ever work optimally on stock spring rate. With higher rate/load springs you can set the LSPV correctly at one weight/height but as soon as you add weight it’ll be under braked at the rear for the load. If your springs are higher rate you’ll have far better braking most/all the time by ditching the LSPV and setting rear pressure with a bias valve.
 
I had a soft pedal despite multiple bleeds. I put all new rubber lines and new calipers all around. Still crappy. The LSPV was a used one I installed a few years back because the original looked like it was pulled up from challenger deep. Visually it looked fine but when we pulled back the boot it was clearly leaking. I put a new one in and it solved the crappy pedal feel. Just a side note but we spent a fair bit of time adjusting it until it stopped right with my two inch Ironman lift.
 
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