Question about rear brake pressure on 80 (1 Viewer)

[FJZ80Lockers]

The brakes on my 80 have always been lacking in stopping power and I wondered if maybe the proportioning valve was to blame.
I am in the middle of replacing the rear axle seals on my 80 and also replacing the rear brake pads which requires the caliper cylinder to be pressed back in (i'm using a C clamp for this). Out of curiosity while the caliper is off, i had an assistant lightly press the brake pedal and i noticed the piston did not move. The brake pedal had to be pressed down considerably before the piston moved much at all.
I'm wondering if anyone else has experienced this? Has anyone had success replacing or updated the proportioning valve or maybe the master cylinder or is abs limiting pressure somehow? Whats the best way to test pressure without a pressure gauge?
Thanks in advance for your help.

 

[silverhorse]

having the same problem.... I'm looking into an adjustable proportioning valve... ill keep you posted... I swapped from rear drum to disk and its never been GREAT when stopping. i swapped to a disc/disc master when I swapped axles but didnt help.

 

[silverhorse]

here's this.. Write-up: Toss the LSPV and install a manual proportioning valve

 

[Heckraiser]

I "fixed" my LSPV by cutting off the arm and zip-tying it in the "all the way up" position--which equates to maximum braking force to the rear. Don't be afraid, the brake balance feels perfect this way. It doesn't feel like the rears are doing too much and they don't lock up or set off ABS before the fronts. Braking performance was DRAMATICALLY improved by doing this simple mod. I'm convinced my rear brakes were simply not doing anything at all prior to the mod. I can now say the clunker brakes better than my 2012 chevy or my wife's acura in terms of brake feel and "bite"

Here is the less ghetto version of the mod, courtesy of @LandCruiserPhil

 

[Eicca]

Best bet is to put in stainless brake lines as well. Guaranteed, your old rubber lines are flexing and absorbing a good amount of the braking force.

 

[FJZ80Lockers]

I'm trying the "cutting off the arm and zip-tying it in the "all the way up" position" method after i replace axle seals brakes etc. and also will seek out that trapped brake line air bubble in the anti lock system. Is there another hidden bleeder valve for the anti lock brakes beside the proportioning bleeder valve i should be cracking open?
if this doesn't work i'm removing ABS and installing adjustable proportioning valve. maybe stainless flex lines too.

 

[jfz80]

Do both sides behave the same?

Any reason you wouldnt suspect a frozen/seized caliper piston? Rebuild is cheap and a new caliper isnt terribly expensive.