hammertyme

I have an 87 4runner, recently I have noticed that the brake pedal goes almost all the way to the floor unless you pump the pedal a few times. as soon as you release pressure it does it again.
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Checked the brake fluid and brakes, they are fine. Was told its possibly the booster.
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Trying to figure out if vehicle is worth fixing. I already know it needs front suspension parts, but since they are all original parts, I'm not surprised.

HighLux

You need to bleed the brakes. Not the booster.

hammertyme

The brakes were fine when I parked the vehicle for a few months. The brake system has not been opened in over 2 years.

angrybob

A few quick checks should tell you for sure if its the booster.

1. With the engine off pump the pedal until its completely hard. Start the engine and note two things: did the pedal soften at all? Second, after a say 10 seconds of idle does the pedal feel any better.

2. The second thing to check is if vacuum is getting to the booster. There is a plastic check valve on the vacuum line going from the manifold to the booster side. Carefully wiggle/twist the check valve to momentarily break the seal on the hose on the booster side. If you hear a hissing, you are getting vacuum to the booster. If not, check the engine side (probably not a booster problem). Go from there.

If #1 is NO and #2 is YES on the booster side, you have pretty much confirmed your booster is FUBAR.

With the engine off, pump the pedal a couple times and hold. Does the brake pedal sink to the floor slowly when you hold pressure? That would indicate a master cylinder leak.

HighLux

Wouldnt a bad booster cause a change in idle when he hit brakes and held them?

I always bleed brakes first in a situation like this, its free...and easy.
Usually a pedal that goes soft but can pump up...is air in the lines.

Toyota~Boy

iTrader: (2)

I just went through this man. My 87 was doing the exact same thing. I finally replaced booster ( upgraded to the 1" booster and master cylinder ) and it fixed my truck. One thing you can check out is a thread I started. It's called.... ( brakes sticking really bad ) you can access it really quick through my profile. Anyways there's a lot of useful info in it.

I bleed my brakes, bypassed LSV, replaced calipers, and brake lines and I still had no pedal. I finally switched out the booster and mine was fixed all except for adjusting the booster. More info on that in my thread.