break peddle STILL goes to the floor

[4Runner_101]

break peddle STILL sinks to the floor

So my friend has a 87 4runner we built, well i built but he did hand me the tools and since we purchased it, the brake peddle sinks to the floor when braking and needs to be pumped. After replacing the master brake cylinder, brake calipers, brake pads and bleeding the crap out of all the lines front and back, the peddle STILL drops to the floor when braking and needs to be pumped in order to stop. Anyone know what this could be?? Theres no leaks at all, i dont see what else we can replace.

 

[tor-redneck]

most the peddle comes from the back brakes. u sound smart enough so im assuming you know, but make sure you got the rear shoes adjusted tight enough. also make sure you bleed the stupid block near the rear axle. i also had a problem with my rear wheel cylenders not engaging. did you replace those when you did the calipers?

 

[wallytoo]

the brake pedal to the floor can be a symptom of more than one issue. air in the brake lines is one. too much clearance between the shoe/drum can be another.

with too much clearance, the initial push on the pedal merely gets the shoes close to the drum or barely touching the drum, and subsequent pumping delivers braking action. once the pedal is released, the shoes retract too far, and you have the same problem the next time the brakes are applied.

 

[MacGyver1979]

does the symptoms change when the motor is not running?
if so the booster, also iv seen the rubber hoses swell like a balloon.

 

[4Runner_101]

most the peddle comes from the back brakes. u sound smart enough so im assuming you know, but make sure you got the rear shoes adjusted tight enough. also make sure you bleed the stupid block near the rear axle. i also had a problem with my rear wheel cylenders not engaging. did you replace those when you did the calipers?

Which block?? is it literally a block? drivers side or passenger??

the brake pedal to the floor can be a symptom of more than one issue. air in the brake lines is one. too much clearance between the shoe/drum can be another.

with too much clearance, the initial push on the pedal merely gets the shoes close to the drum or barely touching the drum, and subsequent pumping delivers braking action. once the pedal is released, the shoes retract too far, and you have the same problem the next time the brakes are applied.

i think you guys may be right, havnt adjusted the rear pads so ill give it a shot, ill check that out today. Thanks!!

 

[tor-redneck]

Id assume its rear brake adjustment.

 

[fourwd1]

By "block" I think he means the LSPV, which is mounted on the pass side frame above the rear axle.
Also, are you bleeding the system in the correct order?
LR
RR
RF
LF
LSPV

 

[fourwd1]

Next question.
If you apply constant pressure to the brake pedal does it feel firm and slow the vehicle at first, then sink to the floor ?
If so, that's a symptom of a bad MC.

 

[VegasT4R]

Brake Booster Leak?

Agree with MacGyver1979. Check the brake booster. There might be a vacuum leak in the booster. You should be able to hear the slight vacuum leak when you apply the brakes.

VegasT4R