Hello all, very strange question about my 01 Blazer (4-door, 4WD). I haven't been able to find any information about this, partly because the question is difficult to explain without writing a novel. Haven't taken it to a mechanic either because the chances of them being able to reproduce it in the shop are probably about zilch. So here goes:

Many times now over the course of the past year (maybe 10-15 separate occasions), I've been pulling into a parking spot and suddenly the brake pedal pushes back against my foot and almost locks in the un-depressed(?) position, the truck continues to try to pull forward as it idles, I can't depress the pedal while it's locked even practically standing on it, and a very loud humming noise occurs from right in front of the foot well while this all goes on. In maybe two seconds, it all stops and the pedal functions normally again. I should point out it's only happened after making sharp left-hand turns into a parking spot followed by braking to stop, or once making a sharp left in a drive thru line and trying to brake (scared me to death as I just barely had enough time to stop the truck from hitting the stopped car ahead of me).

I have no idea where to begin with this. I assume it's an ABS issue, perhaps the system believes the wheels are locking and it needs to release pressure on the brake calipers? I just can't imagine why it only happens when I'm making a sharp left-hand turn and no other time. Short stops even at a fairly high speed work as normal, as does braking during normal driving. Any input is greatly appreciated, I want to have an idea what I'm dealing with in case I get 5 different answers from 5 different mechanics

 

Definitely an ABS issue. Take a look at the tech section, specifically the article on low speed ABS activation.

By the way, the fullsize blazer was never produced in a 4 door nor was it produced in 2001.

 

Thank's for the advice. And yes you're correct about the full-size part, my mistake (too used to my own incorrect slang)

 

I suggest pulling off the ABS module connectors and checking for corroded contacts as something easy to do/check.

Is it possible that a cracked solder joint on the ABS module is the cause of this?

 

You have described the symptoms perfectly. Here is the TSB:
http://ww2.justanswer.com/uploads/GM...s_bulletin.pdf

 

Thanks for the input! I'll be looking into it within the next week when I'm free, will report back on the condition of the wheel speed sensors

 

Let us know if you need any clarification in what needs to be checked and/or how to run through the diagnostics presented either in the link Captain provided or the Tech Article I referred to.

 

It's not that the sensors are bad. Most likely you should be able to remove the front ABS sensors, clean the rust off that is causing too much clearance, and reinstall with some anti corrosion grease. Worked for me. First thing I did on my 2001 here in Indiana. DO NOT get any junk in the sensor hole or you will be buying a wheel bearing - keep the hole plugged with something you can completely remove before you start to clean off rust. I used wadded up piece of paper towel jammed tight in the hole (after making sure the hole was clean of all debris) and then removed it later with a dental pick as a single piece. Cleanliness is next to Godliness when doing this - take it slow and be careful - lots of light to see what you are doing. Put back together with a smear of Birchwood-Casey RIG or Penn Reel Grease. Been through two Winters since with no more ABS problems.

Your alternative is to replace the front wheel bearings.