New yukon owner- Brake issues

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BigJ850

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Howdy all, first time yukon owner and poster. I picked up a 1999 Yukon slt 4x4 5.7 last week and decided to dive into the brakes today. Right off rip I ran into a few problems. My rear passenger brake bleeder was clogged so i replaced it. Next we tried to bleed the brakes and as soon as my 13 year old touched the brake, fluid started shooting out of the master cylinder. purchased new master cylinder, bench bled it and still doing this. Anyone had this issued before? I have traced all lines and cant find any leaks or punctures
 

OR VietVet

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Welcome to the forum.

What @east302 said. Shooting out of master cylinder where? Straight up from reservoir? That is normal with a hard enough push on the pedal. Needs to be done very softly and don't pump it. Needs to be one steady push. Plus, put a piece of 2x4 under where the pedal would hit the floor. Do not let that pedal hit the floor. That can flip the push seals inside the master cylinder. I know how to disassemble to correct that but you may not.
 

Joseph Garcia

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Welcome to the Forum from NH.

Lots of knowledgeable folks here who freely share their knowledge, experiences, and perspectives. Knowledge is power.

I hope that you will become a participating member in the Forum's discussions.

Pics of the truck, please.

You are already receiving sage advice from the knowledgeable folks on this Forum.
 

Eman85

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Let's start at the beginning. You say you dove into the brakes, Why? What prompted you to bleed the brakes? I have a few of these vehicles and they are all over 20 years old so if they haven't been changed it's a good time to replace the rear wheel cylinders if you are doing a brake job on the rear along with all of the springs.
You say fluid was shooting out of the master cylinder, where was it shooting from? Was this with the cap off while you stepped on the brakes?
 

OR VietVet

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Let's start at the beginning. You say you dove into the brakes, Why? What prompted you to bleed the brakes? I have a few of these vehicles and they are all over 20 years old so if they haven't been changed it's a good time to replace the rear wheel cylinders if you are doing a brake job on the rear along with all of the springs.
You say fluid was shooting out of the master cylinder, where was it shooting from? Was this with the cap off while you stepped on the brakes?
I am an "overkill" kind of guy, so I would do drums, rotors, calipers and master cylinder, at that age. Oh, any hoses too.
 

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