scenarioL113

Have a 1995 4runner 22re NO ABS. I have a 1994 4runner with 4 wheel ABS that I was junking. I installed the entire ABS system into the 1995 but had not installed the Master cylinder until yesterday. Everthing has been working great for a few months until now. I installed the Master that was for the ABS equipped vehicle b/c it had the outlets in the right spot to go with the ABS actuator.
I ran the new lines that go from actuator to front and rear brakes and the master cylinder.

I now have a fading brake pedal and cant for the life of me figure out why.
The Master is good (I plugged both outlets and get hard pedal)
Actuator is good (did same as master to it)
Front lines are good (tested same way)

I plugged the outlet of the LSPV and it seems this is where I am getting the bad brake pedal.

There are 2 lines that go to it. One from the ABS actuator and one that comes from the 3-way under the master. (that is how I have them run, please let me know if it is not right)

Does it matter which line goes to which inlet of the LSPV. I may have messed up there but I did switch them and continued to have the same problem.

Is it possible the LSPV got messed up when I bled after I installed the Master.

I am pretty baffled but am pretty sure it has to do with the LSPV somewhere or possibly how it is run with the lines.

Any help very appreciated!

4runnerx3

What order did you bleed the lines? Most vehicles you should bleed the ones that are farther away (by plumbing) from the master cylinder first. Fading pedal is a sign of air, or the rear brakes not working. Several years ago I had one fade, it was the rear shoes not engaging, they got stuck.

scenarioL113

I bled in the farthest first order and the LSPV last as per the Toyota manual.

If a LSPV was blown or malfunctioning what are some of the symptoms.

scenarioL113

All fixed and thanks to all.

The 2nd gen 4runner with 4wheel ABS DOES have a load sensing proportioning valve.

I ended up having some kind of an air pocket in between the LSPV and the passenger side rear wheel.

I had plugged up every fitting one at a time to located where I was getting the fading from. I ruled it to be in the line from the ABS actuator to the LSPV, then I started bleeding.

I bled both rear wheels and the LSPV atleast 6 or 7 times each and was getting a nice strong clear stream. THEN I finally got a powerful air pocket that spewed out with a bunch of dirty frothy fluid. That was it and I am very greatful.

Master cylinder is 179.00 and the LSPV is 189.00 and I needed neither.

Whew, I got off easy.