Brake Issue
#12
03-24-2012, 08:40 AM
Could be a leaky solenoid problem in the EBCM but it also sounds like it could be a bad power brake booster. Unplug the vacuum line at the booster and plug the line with a bolt etc. Drive it, but be aware, you will have no power assist so you'll need to apply considerably more pressure to the pedal to stop the vehicle. Other than needing more pressure, and pedal height being lower, it should stop smoothly without the pedal sinking to the floor. Post your results.
#14
03-26-2012, 09:07 AM
The symptom is very consistent. It seems that the distant traveled and time is the same. Only driving to and from work. The brakes start to drag at the same point and time. I pulled the ABS fuse and there is no change. So what did you do MadBlazer, does the bpmv come with the ebcm, the price I got quoted for the ebcm was about $600.00. I will try your suggestion Captain Hook, the pedal only goes way down on a cold start, like first thing in the morning. It seems to have something to do with the vehicle warming up. After parking the car the brakes hold the car in place, no rolling, after about an hour and a half the vehicle will roll.
Last edited by C210M; 03-26-2012 at 09:13 AM. Reason: more information
#15
03-27-2012, 07:41 AM
Well changed both yesterday and still having same problem.....have replaced hubs hoses calipers master cylinder speed sensors rotors now abs still hasnt fixed my problem...time to say good bye and go get something else
#17
03-27-2012, 09:31 AM
I think we have two manifestations of the same problem..
Madblazer's is the clearest description .. https://blazerforum.com/forum/2nd-ge...-rotors-69423/
But I'm going to suggest they are the same.
Now.. this is the last time I'm posting this. Go get second and third opinions, sooner or later it will come down to checking that pin length.
Everything you need to know on the whys and wherefor's is in the link.
Madblazer's is the clearest description .. https://blazerforum.com/forum/2nd-ge...-rotors-69423/
But I'm going to suggest they are the same.
..
Logically the only thing I can think of would be the pin out of the booster is too long {compared to Master cyl piston position}
If there's an adjustment on the end of the pin, turn it in 2 turns, to shorten it and see what happens. Pedal at brake engagement will drop, of course.
Logically the only thing I can think of would be the pin out of the booster is too long {compared to Master cyl piston position}
If there's an adjustment on the end of the pin, turn it in 2 turns, to shorten it and see what happens. Pedal at brake engagement will drop, of course.
..
If you want to understand the dynamics, here.. read and understand this brake training document.
http://www.autoshop101.com/forms/brake05.pdf
I know most folks dont want to be mechanics but you would be surprised how handy it is going forward.
Most hack professional mechanics dont even bother with this and it's critical.
And btw.. this might be for Lexus but it's universal in principle.
Example:
Is there a gasket on the seating faces now?
Was there a gasket on the original configuration?
What is a possible result of eliminating the gasket?
If you want to understand the dynamics, here.. read and understand this brake training document.
http://www.autoshop101.com/forms/brake05.pdf
I know most folks dont want to be mechanics but you would be surprised how handy it is going forward.
Most hack professional mechanics dont even bother with this and it's critical.
And btw.. this might be for Lexus but it's universal in principle.
Example:
Is there a gasket on the seating faces now?
Was there a gasket on the original configuration?
What is a possible result of eliminating the gasket?
It's not unusual for them to be too hot to hold your fingers on the rotor when braking from highway speed. But you should be able to touch the calipers without burning them.
..we've established they are overheating. Now we're trying to figure out why. ..
..
Pull the the master cyl away from the booster, turn the adjustment screw/bolt in two turns to shorten the engagement rod. See what happens....
..we've established they are overheating. Now we're trying to figure out why. ..
..
Pull the the master cyl away from the booster, turn the adjustment screw/bolt in two turns to shorten the engagement rod. See what happens....
Everything you need to know on the whys and wherefor's is in the link.
#18
03-28-2012, 07:46 PM
Okay, awesome brake booster article, I wish I was a mechanic. I had a mechanic look at my truck and do a diagnosis. He said it was front calipers not releasing. R&R front brake calipers and new front pads. Seemed to be better but the brakes are still dragging when warmed up (10 minutes, 5-6 miles). My mechanic said it is the front brakes not releasing. Taking it back tomorrow. I wonder if the check valve is going bad. Excessive boost pressure after the truck gets warmed up, the pedal does not go down as far as before new calipers when cold.
#19
03-28-2012, 08:46 PM
just food for thought, but here is a similar situation with an envoy (different animal same situation) Front Brakes - Start out fine and then start dragging [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum
#20
03-28-2012, 09:04 PM
Okay, awesome brake booster article, I wish I was a mechanic. I had a mechanic look at my truck and do a diagnosis. He said it was front calipers not releasing. R&R front brake calipers and new front pads. Seemed to be better but the brakes are still dragging when warmed up (10 minutes, 5-6 miles). My mechanic said it is the front brakes not releasing. Taking it back tomorrow. I wonder if the check valve is going bad. Excessive boost pressure after the truck gets warmed up, the pedal does not go down as far as before new calipers when cold.
just food for thought, but here is a similar situation with an envoy (different animal same situation) Front Brakes - Start out fine and then start dragging [Archive] - Chevy TrailBlazer, TrailBlazer SS and GMC Envoy Forum