this is lengthy but please read it all. im not a newb but this ones got me.
i have a 91 civic hatchback. i got it last year for a swap. i did the swap this last winter. i dont know if the brakes worked or not before the swap because i never drove it. anyhow, the swap has been done for months now and still the brake problem exists. here it goes. the pedals are very firm (normal) when the car is off. when it is on, they get really spongy but still work, most of the time. there are recent occasions when the pedal will suddenly go right to the floor and i cant pump the brakes up. i can shut the car off pump the brakes up, turn it on and the work for a bit then right to the floor again. heres what i did to try and tackle this problem.
nope=didnt work
ok, so first, of course, i bled the system. nope. then i flushed the system and put in new fluid. nope. new master cylinder (bench bled) and another bleed. nope. new wheel cylinders in the back. nope. blocked of the booster to eliminate that variable. nope. flushed the lines again...and again...and again. nope each time. pulled it into the garage with a swept clean cement floor and pumped the brakes many many many times, got out and checked the floor for puddles of fluid and there wasnt a SINGLE drop!!!! when the brakes DO work, it locks up all for wheels in our gravel driveway. i have no idea what it could be. i need the pros help on this one.


Modified by tooslohatch at 5:54 AM 7/31/2008


Modified by tooslohatch at 8:41 AM 7/31/2008

 

This similar thing happend with my friends CRX we where driving to the shop to get some stuff done and all of a sudden his brake pedal went right to the floor and it wouldnt brake but if he quickly pumped it i guess and pushed hard it would stop, when we got there we asked about it and he ended up getting on of his rear brake calipers replaced, and the thing was like a spring or a line ro something that was going to the calipers was getting stuck or something but what ever the shop did it, fixed it.
i dont know if that helps at all but i figured some advice is better than no advice.

 

This is a shot in the dark, but does the car have stock brakes? If so, have you tried replacing the proportioning valve? If the brakes are not stock, are you sure that you have the RIGHT proportioning valve? Just a guess...

 

I have some what the same problem except the pedel don't go to the floor... My braking sucks, its all stock, no leaks, and the master and booster are good... Blead them many times and still no go... At least I have a S1 tranny to help out with it...


Alex

 

could be a leak in the brake booster vac lines. or the part of the line that goes into the intake mani could not be sealed properly. you could wrap duct tape around them and see if that corrects the problem.

 

yea sounds like a proportioning valve problem, even with stock brakes ive had old cars i bought and they were neglected to the point that the valve was all gumed up inside. and ive also had the piston that goes from the booster to the pedal worn the f out so bad it was flexing. leaks in the vacuum just leads to a encreadibly hard pedel and you have to have gods arm to push hard enough to stop the car. the prop valve for rear disks should be from 86 -93 teg ive even used 88-91 prelude as far as stock brakes prop valve can be cleaned via carb/parts cleaner the one that has the basket and comes in a 1 gallon or 5 gallon bucket. as for the pedel piston/u type clasp i just found a low milage car in the boneyard $5 part.

 

wow, thanks a lot guys!! yes the brakes are 100% stock. i havent even messed with the prop valve yet. ill clean it out today. i hope that works!!! ill get back to you guys on that. but in the meantime keep the suggestions coming, im running out of options! and again, thank you everyone for the help!

 

jw though, if the prop valve was bad, would i just get uneven braking? and not brakes to the floor?

 

make sure you use a 10mm flare nut wrench with the brake lines, ive already stipped some on my prop valve

 

and I dont know if it is the prop valve...but its worth a shot. from what ive heard, all the prop valve does is regulate the amt of fluid to from and back brakes during extreme braking. I dont think it would affect the pedal going to the floor. that sounds like a MS problem. but you said you replaced that...wierd.

 

ya, im not it sure if its the prop valve, but ill do it anyhow, i have nothing to lose. i ordered another MC from advance. maybe the first one i got was defective. ineed this done by saturday, i have race in mercer!!!

 

ok it wasnt the prop valve. i got a new master cylinder, it wasnt that either. but heres what ive found out. the brakes are normal UNTIL you turn the wheels ALL the way left or right. its ONLY if its all the way turned. i drove the car around to test this again and again and it holds true. they also do this EVEN when the car is off. help me please!!!!!

 

HAHA!!!!!!! found it!!!!!!!! ok so i had put the front struts in from a DA integra so i could quickly change axles without unbolting the strut. well i put them in on the wrong sides so when the wheels were fully turned the caliper hit the wishbone of the strut and couldnt move the piston! im guessing there must be a pressure release valve and thats why the pedals went to the floor!!!!! so i swapped sides with the struts ans its all better. i didnt even neec new wheel cylinders of master cylinder or any of that. well now that i have them in there i have a sick stock brake system. praise God me and my dad figured this out. and thanks for you guys' imputs!!

 

Hello Tooslohatch,
congratulation ! i am not sure how you fixed it. i have the exact same problem. So did you put in new strut??

 

Please, give a step by step procedure i am not a pro like you.

 

You will likely have to buy a time machine and head back to 2008 so can ask him.
This post has been dead for over 10 years!

 

The old post said "caliper hit the wishbone of the strut"; Most likely the strut fork - the two pronged bracket that the strut sits in which attaches to the lower front control arm.

If they are on the wrong side, it can cause clearance issues, and in his case it caused an issue where it interfered with his brake calipers.

Please open a new thread if you need help troubleshooting.