Hey everyone,
Let me preface this with a bit of background. Over the last 6 months I've been having some odd issues with the braking system on my '07 4Runner. It started with my pedal going spongy, and loosing the quick 'bite' (rapid onset of braking force/pressure) it had for most of it's life. Prior to my ownership of the car, it had been serviced at the Toyota Dealership for it's lifespan. I got the rig 2.5 years ago, after it had a full fluid service. During the 2 years leading up to 6 months ago, no maintenance was done besides regular oil changes... Terrible idea, I don't recommend. The sponginess also coincided with the front pads becoming extremely worn down (Less than four millimeters). At this point, I flush the brake system and replace front pads and rotor... It felt great! for a few weeks. Then the sponginess returns and I find myself double pumping the pedal to get enough stopping power. At this point, I begin to suspect air somewhere in the lines, and I purchase a MVCI cable with techstream to bleed the abs system that might not get bled very well. It worked amazingly well, brake feel back to normal.
Jump ahead a few weeks, I loose a brake caliper due to a mounting bracket failure and replace it. The seals on the brake hose washers and bleeder screw are terrible, and even though I torqued both heavily, they still leak slowly. This introduces more air into the lines over time, requiring me to bleed the rear left line once a month to retain adequate braking performance. At this point I'm using the techstream software to bleed my rears, as it's given me the best results.
Tonight I finally got around to replacing the crappy hose washers and bleeder screw that came with the manufactured caliper, naturally after replacing these parts my brakes will need bled. I bleed in order of FL, FR, RR, RL. Before bleeding the fronts, I run the air bleeder utility in techstream to ensure air isn't stuck in the solenoids. ( I should note, I've done this a few times before with good results).
After this process is completed, I go to take it for a test drive and the pedal goes straight to the floor. Essentially feels like there's no pressure. Oddly, as soon as I get close to the bottom of pedal travel the pump kicks in and if I wait a second I have excellent braking performance. It's reminiscent of double pumping my brakes for pressure, except much much worse. The pressure is lost nearly immediately after I take my foot off the pedal, requiring me to 'trigger' the booster pump.
I'm at a total loss as to what could be causing this, any ideas?
Edit:
It's also not throwing any DTC's
Let me preface this with a bit of background. Over the last 6 months I've been having some odd issues with the braking system on my '07 4Runner. It started with my pedal going spongy, and loosing the quick 'bite' (rapid onset of braking force/pressure) it had for most of it's life. Prior to my ownership of the car, it had been serviced at the Toyota Dealership for it's lifespan. I got the rig 2.5 years ago, after it had a full fluid service. During the 2 years leading up to 6 months ago, no maintenance was done besides regular oil changes... Terrible idea, I don't recommend. The sponginess also coincided with the front pads becoming extremely worn down (Less than four millimeters). At this point, I flush the brake system and replace front pads and rotor... It felt great! for a few weeks. Then the sponginess returns and I find myself double pumping the pedal to get enough stopping power. At this point, I begin to suspect air somewhere in the lines, and I purchase a MVCI cable with techstream to bleed the abs system that might not get bled very well. It worked amazingly well, brake feel back to normal.
Jump ahead a few weeks, I loose a brake caliper due to a mounting bracket failure and replace it. The seals on the brake hose washers and bleeder screw are terrible, and even though I torqued both heavily, they still leak slowly. This introduces more air into the lines over time, requiring me to bleed the rear left line once a month to retain adequate braking performance. At this point I'm using the techstream software to bleed my rears, as it's given me the best results.
Tonight I finally got around to replacing the crappy hose washers and bleeder screw that came with the manufactured caliper, naturally after replacing these parts my brakes will need bled. I bleed in order of FL, FR, RR, RL. Before bleeding the fronts, I run the air bleeder utility in techstream to ensure air isn't stuck in the solenoids. ( I should note, I've done this a few times before with good results).
After this process is completed, I go to take it for a test drive and the pedal goes straight to the floor. Essentially feels like there's no pressure. Oddly, as soon as I get close to the bottom of pedal travel the pump kicks in and if I wait a second I have excellent braking performance. It's reminiscent of double pumping my brakes for pressure, except much much worse. The pressure is lost nearly immediately after I take my foot off the pedal, requiring me to 'trigger' the booster pump.
I'm at a total loss as to what could be causing this, any ideas?
Edit:
It's also not throwing any DTC's
Last edited:
