mattwehrly

like most 85 4runners the brakes suck. upgraded the master cylinder. I am not getting much fluid at the rear brakes. the rear proportioning valve has been disconnected from the axle. guessing thats the issue.parts are missing and appears to be froze up. any one removed it? how did you go from the two brakelines to one brake line? thanks!

yotarob2005

Yes you can eliminatethe LSVP. I put a universal proportioning valve on mine. There is a bunch of info in my build thread, I would have to look back for it, but basically you have to block off and eliminate the return line.


https://www.yotatech.com/forums/f199...thread-204726/

See post 178, 191 & 205.

mattwehrly

went outside and looked at the 4runner. toyota had a engineer who went brake line happy! definately gonna be redoing some brake line plumbing! any ideas for going from where the old lsvp was to the axle. got two male ends to deal with.

mattwehrly

seriously with 33" tires is there really any chance of lockup? can i just delete the LSVP and be done?

xxxtreme22r

no. unless you want those crappy drums to have all the brake line pressure rather than the front discs.

on a side note I believe that our master cylinders were not designed to be run without a proportioning valve. something about some sort of valve in the master, but that for right now is above my head as I still don't understand it.

XtraSlow_XtraCab

They can lock up, but thats the price for not having ABS like all of these cushy new cars. Nowadays people are accustomed to being able to just throw the pedal to the floor, but in the old days of drum brakes you have to coordinate pressure to get a healthy compromise between sudden braking and ERRRRRRK SMASH! Skidding is worse than crappy braking.

I'm getting rid of mine. Lift kits screw up the geometry of the load sensing rod, so naturally the LSPV is sensing that my rear tires aren't even on the ground!

My 67 Chevy didn't have that junk. Did I skid sometimes? Yes. Did I learn the ways of crappy ol drum brakes? Oh definetly! Forget the cush and the big sticker price. I'll learn to live with it.

xxxtreme22r

that's why they make brackets for them.

I'm sorry but I would not want to be on any of the roads that are snow covered around here with any of you guys running no proportioning valve.

yotarob2005

You really do need a proportioning valve. Did you see how I did mine? Pretty easy and only cost about $50, I can't see a reason not to put one back on.

waskillywabbit

iTrader: (-1)

Upgrading the brakes...lots of options.
V6 calipers, vented rotors, rear discs, 1" bore MC, dual diaphram brake booster, manual proportioning valve.

Big tires need bigger brakes and brake system upgrades. Period.

:wabbit2:

mattwehrly

guess i will get one ordered. thanks guys

yotarob2005

A simple one will do fine. Here is a pic of my Jegs Proportioning valve with a dual diaphram booster & Tacoma master cylinder

waskillywabbit

iTrader: (-1)

Yep. Nothing to it.



:wabbit2:

Xeo

My LSPV has been cut or the lines going to it that is and i did not do it i bought the truck like that same thing goes for my parts truck..i crawled under there and the lines going to the LSPV were again cut lol my truck brakes fine too should i reinstall it? or just forget it?

Fireball81

The common wisdom (is that an oxymoron?) apparently says to keep it. Or in your case get one and put it back on. Brake line bending is not that complicated just a little intimidating at first. Buy a cheap hand bender and the lengths that you need and get to it.

drew303

Parts List of valve and fittings to make it hook right up:

EAR-989538ERL (Qty 2): Adapter -3 AN to 10mm x 1.0 Inverted Flare
EAR-916103ERL (Qty 2): -3 AN Female to 1/ 8 in. NPT Male
SUM-G3905 (Qty 1): Brake Proportioning Valve, 1/ 8 in. NPT, Single Inlet/ Outlet





I run GM calipers and discs on my rear axle. I run a manual valve and have the stock one still installed and a 1" master. You can manually adjust the the stock LSPV and ewven make an adjustable bracket if with a piece of metal and a eye bolt O===

If you dont run anything you'll rear-wheel lock which is extremely dangerous. In my trial runs with my disc brakes I tested all sorts of different rear brake pressures and for kicks left the line open.. Rear wheel lock is extremely unsafe. You lose all control of the vehicle, period.

drew303

The line 'returning' to the front of the vehicle from the stock LSPV is not a "return" line. It sends the excess fluid and pressure to assist the front brakes.

You can cap the T on your passenger side front wheel well and remove that line entirely if you replace the LSPV with an manual Prop Valve.


Heres a diagram of the braking system (exclude ABS portion if you dont have it - the ABS system interupts the line going to the rear brakes)