1990 N/A coupe's BRAKES always on, VERY stiff pedal HELP

[loganistik]

Hey guys, long time reader, first time poster. Hopefully you guys can help me out.

I just bought a car off of someone who had the car sitting for a while (maybe a month or two) with some needed engine work for cheap. Ive since fixed that issue, but now when i drive the card, it will come to a complete stop on its own, with no need for me to touch the brake pedal. (ill mention right now that the front and rear calipers are good (the fronts are brand new) and I have also just installed new pads all around as well) If i do press the brake pedal, I only have to press it maybe 1/4 to a 1/2 an inch for it to stop faster which is also very stiff, not even enough travel to activate the brake light switch (I know i can adjust the switch, but that doesn't solve the issue)

I will also mention that I have bled and re bled the brakes (including the ABS pump) trying to solve this issue thinking it was air in the lines causing the calipers not to reset. but to no avail.

Also, after having the issue witch i will say isn't all the time, only SOME OF THE TIME, but more often than not it seems. but after having the issue and stopping, ALL of the wheels are emitting alot of heat which points me to the master cylinder/booster.

however from what i've read on here is that a bad booster will make the pedal soft on these cars??? is that true? I do have a spare I can try, however it is alot of work and I dont want to do it for nothing.

what would you guys say the problem is???

Thanks.

[amiry36]

You most likely need to adjust the brake pedal. It could be out of adjustment, since you dont know the history of the car.

A bad booster, if that was the case, see if you have have a hissing sound coming from where the master cyl and booster bolt up. If you hear a hissing sound, it's a bad brake booster. That hissing sound could be random. Meaning sometimes it does and sometimes it doesnt. A bad brake booster cause a stuff pedal. A quick way to test the booster:

There's a vacum line that goes from the manifold to the booster. There is a check valve in the way, remove that. With the check valve removed, focus to the hose that connected to the check valve and goes to the input of the brake booster. Simply suck on this hose, then put your tongue on it. If the hose creates a vaccum, meaning you feel something is holding onto your toungue, then the booster is ok. If it let goes of your tongue, then you know the booster is the problem. Also, of course, make sure that the line connecting to the booster is not loose and causing vacuum leak.

Do those and keep us updated.

Also look at the brake pedal under the dash. There is an adjustment screw bolted inside a clip that is attached to the brake pedal. The head of the screw should be flush with the bracket on the brake pedal.

[loganistik]

I will try the test today after work. sounds pretty easy to find out.

As for the adjustment I will also take a look, However I forgot to mention that if say i'm at a stop light, If i pump my brakes it gets softer aka the next time I go to stop the pedal acts normal, and as I drive it gets stiff again.

Is it possible the check valve is bad? should I try hooking the booster up to full vacuum?

Also, I'm skeptical to say that it is related (though it did happen right away) I stopped the car when the brakes were stopping the car, thought it may be the abs, took the abs fuse out, started the car, then bam, they worked amazing. Though later on that night they became stuck again.

Hope that helps

[loganistik]

another note on the car is it requires very little movement and effort of the pedal to actually stop the car, If i push the pedal more than say 1/2 inch, Im going through the windshield, so to say.

[loganistik]

So if anyone else is having this issue

It seems to have been a very old stiff hose that wasn't sealing the vacuum very well going to the brake booster (hence why it would kind of but not really)

For the time being I've run a hose strait to the booster and it seems to be working perfectly.

Thanks for all the help.