Hello I'm Dan and i singed up here cuz my gf is driving a 87 k5 Blazer. and what i have a consern about is last night she was driving it at bout 50mph and she went to press on the brake and it was like hitting a brick, it didnt move. she got the trck stoped and such but what is wrong with the truck? is it common for the truck of this year?, and how much is a new whatever it is?. Her mother has it in her mind that the truck is fine, but i think when someone tells me that if you press on the brake and nothing happens i would be conserned, and as I am. Thanks for all the hekp that I'm about to get.

Thanks, Dan

 

Welcome to the forum.
An easy test of your brake booster is to push on the brake pedal with the engine off. Keep your foot on the brake and start the engine. The pedal should go a little lower as the vacuum in the booster adds assist. If the pedal doesn't go down at all, pull the check valve out of the booster (at the end of the vacuum hose) leave it connected to the vacuum hose and make sure the vacuum is coming through the valve.
A rebuilt booster might be about $150.
The booster is fairly easy to change, just remove the 2 nuts holding the master cylinder on and slide it forward (leave the brake lines connected.
Then take the brake switch off the brake pedal lever and slide off the pushrod from the pedal.
Remove the 4 nuts on the back of the booster. pull the vacuum hose off the valve on the booster and slide the booster out.
Reverse the procedure to install.

 

ok well ill check that when i go down, her mother is a pain and im wondering if she'll let me drive it for a lil to try to recreate the problem. thanks again. ... how do you fix a lose steering wheel, like the wheel has a lil give in it, so its hard to keep straight.

 

Yeah, I'll throw in another vote for the booster either not getting vacuum (check valve) or the booster itself being shot.