Dragging brakes 2004 Yukon

[Run4st]

Hello all. Been lurking for a while …not posted much. First let me say I have searched forum before asking. Did find a few ideas.

I got a 2004 Yukon SLT. 149k on odometer. It sat for close to 2 years before I purchased it.



Problem is brakes sticking/dragging.
Back brakes were worse.

Flushed old brake fluid (very dirty).
Replaced rear calipers and rubber lines that goes from caliper to hard lines on both sides in rear.
Replaced front calipers.
Pads and rotors were fine in front and back. Hard line in back look very good (think they were replaced---no surface rust on them). Petal seems soft after bleeding them… couple days later went to drive it and pedal went to floor. Found no leaks on ground at all. Replaced brake master cylinder.
Bleed them again. I got a better pedal than before but still something doesn’t seem right. To come to a complete stop pedal maybe has 4 inches or so from floor.

When pedal released it comes back up it doesn’t pop back up very fast. Seems slow to me. I did not smell brakes burning. Went to another place and could smell the front driver burning smell. Yes it is most def the brakes. Drove it home and no burning smell (brake dragging). Still feels odd (kinda soft) and slow return of the pedal when braking.



Brakes were fully bleed each time I worked on it. No ABS lights ever. No error lights. Still have not done front rubber lines or messed with ABS block.



Back brakes don’t seem to be sticking/dragging like before. Those of you driving this gen Yukon/Tahoe are your brakes soft with a slow pedal return?



Any ideas/personal experience is helpful.

 

[Fless]

Is this a vacuum assist, or a hydroboost brake system?

 

[Scottydoggs]

id change the front hoses, and if theres one in back to the rear end center.

if the master has ran dry good chance you pushed air into the abs pump, then you'll need a tech 2 scanner or snap on ect to bleed the brakes so the abs gets cleared out.

 

[justirv]

Hello all. Been lurking for a while …not posted much. First let me say I have searched forum before asking. Did find a few ideas.

I got a 2004 Yukon SLT. 149k on odometer. It sat for close to 2 years before I purchased it.



Problem is brakes sticking/dragging.
Back brakes were worse.

Flushed old brake fluid (very dirty).
Replaced rear calipers and rubber lines that goes from caliper to hard lines on both sides in rear.
Replaced front calipers.
Pads and rotors were fine in front and back. Hard line in back look very good (think they were replaced---no surface rust on them). Petal seems soft after bleeding them… couple days later went to drive it and pedal went to floor. Found no leaks on ground at all. Replaced brake master cylinder.
Bleed them again. I got a better pedal than before but still something doesn’t seem right. To come to a complete stop pedal maybe has 4 inches or so from floor.

When pedal released it comes back up it doesn’t pop back up very fast. Seems slow to me. I did not smell brakes burning. Went to another place and could smell the front driver burning smell. Yes it is most def the brakes. Drove it home and no burning smell (brake dragging). Still feels odd (kinda soft) and slow return of the pedal when braking.



Brakes were fully bleed each time I worked on it. No ABS lights ever. No error lights. Still have not done front rubber lines or messed with ABS block.



Back brakes don’t seem to be sticking/dragging like before. Those of you driving this gen Yukon/Tahoe are your brakes soft with a slow pedal return?



Any ideas/personal experience is helpful.

As @Scottydoggs mentioned, the master cylinder/ABS bleed with a Tech2 made a huge difference for me. @Fless asked whether hydroboost or vacuum, which gives two variants on activation issues and possibilities. If your rears were still dragging, I have seen the parking brake dragging inside the rear rotor hat.

 

[rockola1971]

Take it for a spin and hit each rotor with a IR gun and see which one(s) are running the hottest. There's your sticking calipers. And Id bet that you have air in your ABS manifold if youve never ran a bidirectional scanner to bleed the system. There usually is just no way around it.

 

[Run4st]

Is this a vacuum assist, or a hydroboost brake system?

It is a Hydro

 

[Run4st]

As @Scottydoggs mentioned, the master cylinder/ABS bleed with a Tech2 made a huge difference for me. @Fless asked whether hydroboost or vacuum, which gives two variants on activation issues and possibilities. If your rears were still dragging, I have seen the parking brake dragging inside the rear rotor hat.

Rears have seem to cleared up (so far).

 

[Run4st]

As @Scottydoggs mentioned, the master cylinder/ABS bleed with a Tech2 made a huge difference for me. @Fless asked whether hydroboost or vacuum, which gives two variants on activation issues and possibilities. If your rears were still dragging, I have seen the parking brake dragging inside the rear rotor hat.

It is a hydro...Whenever I get time I will do the front rubber lines and then find someone to do a Tech2 bleed

 

[justirv]

It is a hydro...Whenever I get time I will do the front rubber lines and then find someone to do a Tech2 bleed

I understand the premise behind hydro, and want to do a conversion, but I have no first-hand experience with them. Could a leaky (internal) master cause pressure from the PS circuit to apply (light) brake pressure? We'll wait to see what our resident experts say.

 

[Run4st]

Update: Replaced the rubber lines on front (connects caliper to hardline). Got brakes bleed using tech tool...night and day difference. Had heck of a time getting air out. Think it might have gotten in ABS manifold...Thanks for the suggestions.