Hi everyone i need help diagnosing a problem ive been having with my 97' blazer 4x4 4.3 LS. I was reversing out of a parking lot and once i got on the road and put it in drive and drove for 2 mins the brake pedal siezes up and i cant use my brakes and the engine makes a continous loud cliking grinding sound and the truck actually pushed me through a stop sign twice now! I had to put it in nutural and come to a rolling stop then restart my truck and all is well after that until the next time it happens? not sure what it is, any help on this one is appreciated.
thanks

 

i have the smae problem is very dangerous i dont know if is the passlock or security box i have a blazer 97 v6 4*4 please help me

 

I had a similar problem a couple months ago in my 97 blazer 4x4 LS. My brake pedal became very stiff and i had to stand on it in order to stop. My brake booster had gone bad and after I got the new one in the brakes went back to normal.

 

Sounds like the brake booster to me. Or the master cylinder.

 

if its an intermittent issue, it sounds more like a malfunctioning ABS module than anything. generally when a brake master goes bad, you get a soft pedal, and when a booster goes bad, you get a rock hard pedal but a booster failure isnt really ever an intermittent thing. the clicking youre hearing is probably the ABS module cycling. i would service the ABS pick-ups in the hubs by thoroughly cleaning them and making sure the wires arent damaged. also remove the one way valve from the brake booster and make sure it functions properly. get dirty and put your mouth on it from the booster side. you should be able to blow through it, but not suck. its also a good idea to service all of your brake components to make sure nothing is seizing or binding.

 

I've had brake boosters break on me before and you can still stop. Its just harder. Lost mine in a k5 towing a empty trailer. Had to use 2 feet to stop but it did

 

If the ABS is acting up, could it be the sensors in the front wheel hubs? Isn't that a common problem? I just had my front hubs replaced (but I never had an ABS problem) and it is not that expensive if you go to the right place. If it is the ABS, I would try pulling the big ABS fuse (under the hood, 60A. The ABS light will light up within one minute of you starting the engine after you pull the fuse. That is normal.) first to disable the ABS and then see if the car stops normally. If it does, then the problem is limited to the ABS system. If your ABS light is on (with the fuse still in of course), have the ABS codes read by an ABS scanner. Normal OBDII readers can't touch the ABS module. If it is wheel hubs, however, that might not throw a code because the ABS module cannot detect a problem with it. The hubs are basically giving the ABS module bad information and the module thinks the wheel is locking up when it is not and the ABS kicks in to release the brake until it thinks that the wheel is spinning freely again.

Also, if you take the truck to shop, be careful who you take it to. Just check out my thread "Brakes failed on highway" because I had nothing but problems with this one shop when they unnecessarily replaced the master cylinder. It was the rear calipers. Now, that might not apply to your situation, but I am just saying, make sure you take it to several shops for estimates first and find out who does quality work. I once had a $1200 estimate for the front wheel bearings in this small town. It was a store that was part of a huge chain. I went to the next town and had it done for $292 at a local business (NOT a chain), but it was $325 because I also had them rotate the tires and put a new fuel filter in. Not to mention the service was alot better.

 

Ok guys i got it back from the shop today and yes it was the abs module, after going over everything to do with my brakes and found nothing wrong all we had to do was unplug the connector on the middle/left side of the abs module! The abs light is on now but i don't have that problem anymore.
Thanks for the help guys!!!

 

Try calling ModuleMasters. Their site says they cannot repair the module in the S-10 series (only fullsize) unless the problem is a pump motor running continuously, but email them with your situation and maybe they can work something out. Maybe they can fix it if the problem is similar.

P.S. If you unplugged a connector, make sure to protect it somehow so if and when you get the module repaired or replaced (also check u-pull-it yards), the connections won't rust and make it impossible to plug it in again.