soft brake pedal- low RPM's

[willyt4r]

My original symptom was that while braking at slower speeds the brake pedal will go all the way down without having additional braking. My first replacement was the master cylinder. The result: Same problem,since it was a rebuilt unit , I purchased a new master cylinder and had the system bled at the mechanic's shop. Still the problem persisted, next was the replacement of both front calipers. Still the same issue. Soft brake pedal in lower RPM's.
I have checked the brake booster according to the FSM. Engine off -the pedal holds for three pumps- start the engine and the pedal perks back up.
I am at a lost. :crybaby::crybaby::crybaby:
1991 V6 4x4 fresh engine 6000 miles

 

[fourwd1]

Your description does sound like a MC internal leak
Was the new MC bench bled?
Next, did you bleed the system in the correct order?
LR
RR
RF
LF
LSPV

 

[willyt4r]

LSPV replacement was the fix

The cure for my fading pedal was the LSPV replacement. No matter what method was used to bleed the brakes ( two man team, mighty vac, Professional air bleeder) the pedal just never felt right. The dealer only part ( $182) Redlands Toyota was pricey but since my Rig is a DD for Snow I didn't want to put in an aftermarket bias valve. Still cheaper then a paymant.
toyota part 47910‑35150 :trophy: