Mechanics cannot resolve brake problem

[JMatATech]

I saw a useful thread on brakes from a few years ago, but note that in my case the master cylinder and booster HAVE been replaced with OEM equipment.

2007 Chevy Equinox (93,000 miles) has performed perfectly from day one. Two weeks ago, after a new REAR brake job at a tire/brake dealer, brakes have been seizing up simultaneously. Tire brake dealer could not solve. Second mechanic changed FRONT brakes, master cylinder (OEM), booster (OEM), and rotors. The removed booster had more than a quart of liquid in it. Brakes again seized up simultaneously. Computer codes indicate nothing is wrong, and second mechanic cannot explain. Third mechanic says computer codes indicate nothing is wrong, but would like to change the new master cylinder and booster for ANOTHER new master cylinder and rotor to see if that works. I need a solution that’s not guesswork!

 

[JCH13]

In my (admittedly limited) experience with brakes dragging or seized brakes are almost always brake caliper slides. I'd hope that when your mechanics did a 'brake job' they cleaned out all the slides, re-greased them, and replaced any damaged boots. However, I wouldn't be surprised if this step was forgotten, ignored, or done very poorly.

Don't throw any more parts at your car until the calipers/caliper slides are checked out.

The other obvious derp this *might* be is a very poor adjustment of the e-brake. I don't know what sort of system your car uses or if it's prone to jamming, but it's a possibility since all of this started after the rear brakes were done, and the e-brake would have been futzed with as part of doing rear brakes.

 

[silicon]

Absolutely find a mechanic that understands brakes and how they work...you are dealing with part changers and this is expensive for you. Just wondering if they even give some rationale as why they changed all of these parts. Again find a real mechanic and not one of these chain store garages.

 

[JMatATech]

Thanks for the suggestions; we'll follow up and post the outcome. BTW The first mechanic was a franchise. The second was trusted independent mechanic and the third was the dealership. Do you consider dealership brake experts?

 

[manimal]

Possible abs jumper wiring harness issue? Have dealer check that.dealer part #15773652 A few equinox's I saw a few years ago had these go bad causing brake issues. Both needed a new abs harness.

Also check for kinked brake lines. Sometimes they get a bend on em making them a one way valve....

 

[silicon]

Thanks for the suggestions; we'll follow up and post the outcome. BTW The first mechanic was a franchise. The second was trusted independent mechanic and the third was the dealership. Do you consider dealership brake experts?

did your trusted mechanic give an explanation of why those parts were changed?

 

[soccerballtux]

being a chevy looks like it's near the end of its life anyhow. might as well trade up

 

[JMatATech]

Thanks for the harness suggestion, which I'll relay to the garage. On the Trusted Mechanic explanation, I think it was along the lines of "it has to be one or the other and it's cheaper to change both at once." That's the dealership's viewpoint also! At the TM's garage, the booster was found to have lots of brake fluid in it.
And yes, trading up is looking good right now! We're just hoping to have something with which to trade!

 

[boomerang]

"seizing up simultaneously"

What exactly does this mean? Both rears are locking up simultaneously? All four are locking up simultaneously? Light brake application, moderate application, hard application, no application?

The problem did not exist prior? Rear brakes are serviced and the problem surfaces. Common sense dictates that the problem is with the work that was done on the rear brakes. My initial guess is that the wrong brake shoes have been installed or the hardware has been reinstalled incorrectly. If the shop that did the initial work found nothing wrong with their work, (but did it wrong the first time and cannot recognize their error) then it would be important to have another shop inspect their work.* Has that been done? I too think it's related to the parking brake. Wrong shoes or hardware installed incorrectly is my guess. But without answers to my questions it's a guess and without having the car in front of me everything I suggest will also be a guess. I don't envy the position you are in.

Edit: Rock auto shows your car having rear drums so I am making an assumption it has drums.

*You did not specifically say that shop two took a look at the rear brakes which is why I am asking.

 

[phucheneh]

If you raise the car in the air, can you literally not spin either rear wheel?

It sounds like the first people to touch it were complete fools. And the second people just wanted your money, which you gladly handed away rather than keeping the first shop on the hook for the botched rear brakes.

They may have installed the pads wrong. I've seen inner and outer pads that will hang if installed in the wrong position. Some moron may have shoved the piston back into the bore by pushing on one side of it with a pair of channel locks, and wrecked the seal. They may have installed new aftermarket hardware that doesn't fit worth a damn and is making the pads stick. They may have greased the pins with whatever garbage grease they had laying around, and after being heated it has turned to gummy shit.

Lots of things can come from stupid people working on your car. Learn to hold them liable.

 

[Billb2]

Caliper rebuild. The pistons are cocking in the calipers.
When the brakes "seize up" are the wheels hot too?

 

[master_shake_]

Haven't been under an equinox lately but are the rear shoes for the parking brake broken and binding?

Are there brackets that hold the brake hoses that are constricting them?

Is the rear diff if equipped the culprit?

 

[colorblind]

I saw a useful thread on brakes from a few years ago, but note that in my case the master cylinder and booster HAVE been replaced with OEM equipment.

2007 Chevy Equinox (93,000 miles) has performed perfectly from day one. Two weeks ago, after a new REAR brake job at a tire/brake dealer, brakes have been seizing up simultaneously. Tire brake dealer could not solve. Second mechanic changed FRONT brakes, master cylinder (OEM), booster (OEM), and rotors. The removed booster had more than a quart of liquid in it. Brakes again seized up simultaneously. Computer codes indicate nothing is wrong, and second mechanic cannot explain. Third mechanic says computer codes indicate nothing is wrong, but would like to change the new master cylinder and booster for ANOTHER new master cylinder and rotor to see if that works. I need a solution that’s not guesswork!

Have the bpmv inspected-brake pressure modulating valve.

 

[JMatATech]

I can't tell you how grateful I am for the resourceful thinking all of you have shared. As of today, the dealership (SHOP THREE) has released the car back to me, did not charge the diagnostic fee, and takes the position that everything SHOP TWO did was wrong. And, did they check the items we forwarded to them yesterday (from this helpful forum), "yeah, yeah, yeah, of course."

We'll draw up a checklist of every suggestion presented in the forum and get confirmation on every item from SHOP TWO. I'm sorry, even though in my heart of hearts I think SHOP ONE, the franchise, is the cause of the problem, I can't bear taking it back over and over to a shop that I don't believe is capable of fixing it, and driving with dubious brakes is too risky. They will no doubt claim that a rear brake job had nothing to do with the master cylinder failure (IF it failed) and with the booster having brake fluid in it). If we can find out that something was damaged during the brake job we absolutely will go after SHOP ONE.

I'll report back when we get further news. Thank you, thank you, thank you all again!