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Not pumping brakes after brake job

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Old May 1, 2011 | 12:38 PM
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Default Not pumping brakes after brake job

Did 4 different bakes jobs for friends over the past few weeks. All went well. Decided to do the Bonny’* front quickly after work. My wife called and asked why I was not home yet (work on the Bonny at a garage about 20 miles away), told her I was doing the brakes and she said get home or else….

I finished up the brakes, did a visual check and everything looked fine. The garage I rent is on a main street in a small town, with a children’*’ dance studio next door. As a backed the Bonny out (garage door is blind spot) I hit the brakes to check for children. The Bonny didn’t stop at all, brake pedal to floor. I kept pumping as I drifted into the middle of main street. Right when I hit emergency brake, the brake pedal went firm.

Guess it took a while for the pistons in the caliper to grip onto the pads/ rotor. The back brakes didn’t grab. Could have hit a kid or another car, etc. In an open area, no big deal. But on main street full of cars and kids, a very big deal.

Lesson learned- always pump the brake pedal until firm before moving a vehicle after a brake job. Common sense, but I lacked it that day.
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Old May 1, 2011 | 02:09 PM
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That happened to me once, did a 4 wheel brake job. The owner jumped in and started it, before I could say anything it went in to drive. I jumped out of the way just as the car ran in to my work bench. Owner had very big eyes. I calmly said, you might want to pump the brakes first.
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Old May 1, 2011 | 04:15 PM
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Always verify that your job is done properly before you drive!
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Old May 1, 2011 | 04:55 PM
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That'* air in the hydraulic system for ya. Been there, done that, wasn't in drive.
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Old May 1, 2011 | 10:04 PM
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brakes 101 , one of the first things you learn,
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Old May 2, 2011 | 12:28 AM
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almost did it before, thank god someone pointed it out
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Old May 2, 2011 | 12:30 AM
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Coulda done what happend to me..I picked truck up to do brake pads..got em swapped pumped the brakes and they locked up..The owner of the truck had checked the fluid and didnt put the rubber peice inside the master back on right and it got sucked into one of the holes blocking it
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Old May 2, 2011 | 07:25 AM
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X2 on checking everything out before moving the car.
Threads about safety keep recurring on this and most other car forums. One time in 1000 we might be reminded to do something that might save a life. We all make mistakes, I've made a few and doubt if I've made my last.
If you are doing safety related work the time taken to double check that everything is ok is never time wasted IMO.
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Old May 2, 2011 | 07:33 AM
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Originally Posted by SignOfZeta
That'* air in the hydraulic system for ya. Been there, done that, wasn't in drive.
Incorrect sir.
When the piston is compressed in the caliper the fluid travels back to the MC res. It takes a few pumps to refill and push the piston back out to the point where it'* almost grabbing.

Say the piston position requires 5cc of fluid before you do the brake job. Then you compress all but .5cc out of the piston when doing the job. One push of the pedal only moves 1 cc of fluid. So if there is .5 cc in the piston and the new pads require the piston postion to have 2cc of fluid. You'll be .5 cc short on the first press and the brakes won't engage because there'* not enough fluid in the piston cylinder.
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Old May 3, 2011 | 10:36 PM
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Originally Posted by Danthurs
That happened to me once, did a 4 wheel brake job. The owner jumped in and started it, before I could say anything it went in to drive. I jumped out of the way just as the car ran in to my work bench. Owner had very big eyes. I calmly said, you might want to pump the brakes first.
Its ok dan you could of said who it was lol, rookie mistake. Won't ever happen again but I did a good job going back and forth before I lightly got the work bench. I didn't think I jumped in before you said anything I think we both forgot lol
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