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Discussion Starter #1
Hey guys.. my name is Justin.
I am the owner of a 2005 Trailblazer EXT 4WD. I've had the truck since November of 2018. It was bought used with 164k miles on it. I used to have an 06 Envoy SLT and loved it but sold it to help finance a small business... when I found this one... I got it.

Now onto the issue...

Brakes. Yay! Here's the time line of what's happened:

  • March 2019: LF Caliper sticking. Replaced LF & RF Caliper, Rotors & Pads. Issue didn't stop.
  • April 2019: Changed RF Brake Hose. Figured the brake hoses may have collapsed. Tried to change the LF Brake Hose but was rusted to the brake hardline and I didn't want to mess with that. So... for the past 4 months... while driving under normal braking the brake pedal will tighten to only about 1/4" of travel within 5-7 miles. The LF caliper will engage and slow down the truck pretty bad. The RF caliper doesn't do it nearly as bad but you can still see marks on the rotor from the pads being engaged. If I stop for a while the pressure goes away. While the issue is at it's worst.... if I pull the brake master cylinder cap off there's a good bit suction when the cap is removed.
  • June 2019: Finally had the LF Brake Hose & hardline from the ABS controller replaced. Warrantied the caliper due to a stripped bleeder valve. The brakes will intermittently show the same issue as before just not as often but now the brakes smoke real bad. They've never smoked before.
No brake/ABS lights on the dash.

What could be causing the issue? I've heard that the Tahoe sometimes has the same issue being that the ABS System is the same that it could be a valve stuck in the ABS Manifold... not the actual ABS Controller. Someone also said it could be the proportioning valve.

I need help guys! This is draining any bit of money in my bank account and I can't afford to keep guessing.

Thanks!
 

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Okay here are some very hard questions that need to be answered First I will need to set up the diagnostic test procedure.

Jack up the truck on 4 jack stands. Motor running transmission in neutral.

Hit the brakes, have another person rotate each wheel forward the moment you release the brake. Do this with all 4 wheels.

Which wheel is still binding within 1 to 3 seconds after the brake pedal is released?
Listen for any odd ball brake noises coming from the brake assemblies and or ABS pump.
With brakes lightly applied, what wheel assembly can still rotate where the others are locked in place???

Report

Next, was this truck "pumped bled", "pressure bled" or "suction bled"???

One of these methods is a "forbidden procedure" with ABS and locks the ABS unit up even with the key in the off position. A lot of the license mechanics and technicians are still very ignorant to the proper bleeding procedure after 30 years with variants of ABS.

Report what (every) method was used by any body with the first and second bleeding times. Be truthful !!!

Next install a scan tool that can read ABS codes and can do brake system reset procedures.

That will tell me what might be going on.

As for the people giving you possibilities, listen to the ones who have diagnostic capabilities, not guesstimators.
 

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One of these methods is a "forbidden procedure" with ABS and locks the ABS unit up even with the key in the off position. A lot of the license mechanics and technicians are still very ignorant to the proper bleeding procedure after 30 years with variants of ABS.
Which type of brake bleeding is a forbidden procedure for the 2005 Trailblazer?
 

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You have to tell me that first!!!

When I tell them which one, … they tell me 100% of the time they didn't do it, then I break out the scan tool and found out they did that procedure.

I need to validate what is going on with you brake system. I gave you questions, need some answers to send you in the right directions.

As for a Trailblazer procedure, … no, it's the one procedure that is forbidden with any ABS style vehicle for the last 30 plus years.
 

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Discussion Starter #5
You have to tell me that first!!!

When I tell them which one, … they tell me 100% of the time they didn't do it, then I break out the scan tool and found out they did that procedure.

I need to validate what is going on with you brake system. I gave you questions, need some answers to send you in the right directions.

As for a Trailblazer procedure, … no, it's the one procedure that is forbidden with any ABS style vehicle for the last 30 plus years.
I'll see if they even tell me what type of brake bleeding they did. I'm not sure I want to go back to them.
 
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