This is whats up, been haveing this problem on my hatch since I got her,with my brake booster. Hooked the way it supposed to be after drive for awhile the brakes slower start sticking,gets to the point were they end up locked up,but with the vac lines not hooked up to the booster they do not do this.
Ok on to things I have done so for to figure this out,now remeber did this since day on all stock,since I have put rear si disc in back,change prop valve to a 40/40 or 50/50 whatever it needs for rear disc,si brake booster,and brand new valve thing can't think of the name from honda that goes to each vac. hose on top the booster.New si master cyl.
Could this be a problem with the intake manf.? Has anyone esle had this problem?My brakes work now, but have no booster hooked up so not the easiest to stop. Been dealing with this for awhile just really would like to get an answer on how to fix this. Oh more thing the brake fluid has been changed twice.

 

you probably did this, but I might as well ask anyway.
Did you try flipping the booster vacuum valve around?

 

Yes sir and then looked it up to make sure it was right,damm nobody ever had this problem? This is why it has never got fixed yet...lol don't know whats wrong with the damm thing,what would cause the brakes to engage them selfs? I've ask myself this question over and over again....

 

It looks clear that your problem is not with the hydraulic portion of the brakes.
Without the vacuum assist everything works fine.

There are only 2 parts to the vacuum system - the one way valve and the booster.
First you should get a service manual or look up the info for testing a booster.
(It's been posted here before so you may have some luck using search.)

I can't remember anything that points out a failure like you are experiencing.
Usually a booster failure creates a vacuum leak.
In your case it seems like opposite and the booster seems to be holding in too much vacuum.

Since you have a brand new valve then I have to assume it's working well, but since they are cheap it may be worth changing out. If you have your old one, give that a try.

 

are you using a 15/16 or 13/16 mc and bb combination on your setup...if your using the stock 13/16 setup with a 4040 valve on rear disk's it will cause your brakes to lock up.

either switch back out the 4040 valve for the 3030 on your 13/16 setup or upgrade to the 90-91 civic ex setup and use it with the 4040 valve.

 

Well thanx big,you may be right never thought about that.The only is that the car has always done this even bone stock same problem do you think it could have something to do with the intake manf.?

 

try the remedy i discussed earlier because using them mismatched wont make a right and will cause your brakes to lock up.

*13/16 master cylinder and brake booster=3030 valve
*15/16 master cylinder and brake booster=4040 valve

these two combination of setups wont work correctly if mix and matched since the proper fluid distribution would be no bueno.


btw the saints beat my team last week by luck but i still go for them in the super bowl since i cant stand peyton manning

 

Ok going to check on that tonight thanx,and the Saints thing I'm been wating on my whole life for them to get to the superbowl....were takein this **** all the way! Black and Gold in the superbowl....lol because COLTS stand for Count On Loseing The Superbowl!