JRapture

Okay so I just replaced the brake lines, and rotors on the front of the car. The pads were replaced back in august of last year.

The problem is: the brake pedal is really stiff, and when I put the car in neutral to coast it is like the brakes are being applied and the car will stop itself. This usually only happens in the main heat of the day 80 degrees +, it also has a slight vibration to it after driving for about 15 minutes. It has been reduced from what it was after I put the new rotors on it.

Any solutions or ideas?

TearSDMF89dx

how did the calipers and slides feel when you pushed them back for the pads? ....any tight spots? sounds like a stuck caliper to me also did you check you rear brakes to make sure they were free?

JRapture

The calipers and slides felt fine, but I will check again to make sure. And no I have not checked the rear brakes, so I will check that as well

Riceburner247

iTrader: (1)

Bump, because I'm having this exact problem on my 89 civic si. Car sat for a year before I bought it so I went through the brake system.

Car now has:
New brake booster
New 15/16 master
used 4040 prop valve
New steel braided lines
stock front brake system(caliper, rotor, pad, etc)
stock rear disc setup from a 90-91 DA
ATE Super Blue fluid

I was driving to a friends house today(60mph) when I noticed my steering wheel started shaking. Then a minute later my speed started dropping no matter how much gas I gave it. 5 minutes later, I was flooring it in 1st because that's the only gear that would maintain speed. It acted like someone was standing on the brake pedal the entire time, the pedal had NO GIVE. Once I pulled into my friends driveway, the car stopped and wouldn't move again. The clutch slipped in 1st trying to get the car to roll.

It's only the front brakes, they're hot as hell. The rears are luke-warm if not cold. I was able to take a bucket of water and douse both front calipers until they cooled off, then got back in the car. The brake pedal had gone from stiff, to now almost to the floor.

I'm pretty sure this means that the caliper is sticking, but if anyone could confirm this that would be great.

94eg!

iTrader: (2)

To me that sounds like your the push-rod from the pedal to the booster is out of adjustment. If the pedal keeps slight pressure on the master cylinder at all times, it will make the brakes drag. If they drag, they get hot. If they get hot, the fluid expands. If the fluid expands, the brakes will drag worse. This cycle continues until your brakes finally seize up and your car won't move.

Get under the dashboard and adjust the push rod to add a little more free play to the pedal. It should turn counter-clockwise like your unscrewing it. Do it until you have a little free play in the pedal and then take it for a test drive.

BTW: Your foot probably goes to floor now because you boiled the brake fluid. You should definitely replace the brake fluid as well.

civicfanboii27

we call this brake drag. sounds like your caliper piston is stuck. Did you compress it when u were replacing ur parts?

jsinher3

have you messed around with your brake booster house? theres a a resrticter on there and if its not facing the right way it will make your pedal hard as hell and not make them function right..

GElite

I had the same problem on my bike after it sat for a while. Got moisture in the caliber and it pitted the piston and for some reason everytime the breaks got hot they would clamp down. I would have to open the bleeder to release the pressure. Dont have a solution for you other than new pistons, thats what I did.

Riceburner247

iTrader: (1)

I didn't have the exact tool to measure the free play between the booster and master, but since I had both new out of the box, I bolted them together on the bench. Got it really close if not right where it should be. Already adjusted the rod twice now that it's in the car, I've adjusted the nut on the back of the booster about 3 full rotations counter-clockwise, brakes still lock up. I was thinking of that exact symptom of the brake fluid, though! But I figured brake fluid was designed to not expand or contract.

Yep, compressed the front pistons all the way while the car was on the lift. Took the car up to 80mph while on the lift(no brake noise), then hit the brakes as hard as I could. Took the car back up to 80(slight pad drag noise). I thought the surface rust needed to be worked off.

Need more info on this. My pedal is pretty firm, but probably because of all the upgrades.

Thanks for the input everyone. I have 90-91 DA complete front spindles that will be going on the car, so I think the problem will eventually be eliminated. I need to replace everything on those before install, I was just trying to make the stock fronts work till then. If I have time, I'll pull the problem calipers apart to see if there was an internal issue.

Riceburner247

iTrader: (1)

BUMP

Finally had time to work on this situation again today. Both front corners got new calipers and brake pads. I thought the old stock calipers were the issue. Once pads were in, went to push the piston back into the caliper, wouldn't move. Had to crack the bleeder on both calipers just to get the piston back in. Something in the system is acting like a 1-way valve. Once pressure is applied, it can't be backed off.

I'm starting to think its a defective proportioning valve. It's next in line heading back from the front corners, is the only thing that isn't brand new, and is something that would affect the front wheels separate from the rear. Does anyone have any experience or has anyone heard about these things going bad? Or how to test one? I would think I could just blow compressed air through the ports, but not positive. I wish I had saved the stock valve that came out....

Jarrydcrxsi

ok guys im having just about the same problem.. Both front brakes are locking up, in the past few days i have replaced the booster and the master, bled all the lines and made sure there were no air pockets? not sure what to do, my buddy was the one that actually adjusted the booster rod but i dont know if that would be it. Advice please, thanks

RighthandRex

I know this is a fairly aged post, but an answer to this question would be great!! I've got the same issue happening.

Tyson

Booster pushrod adjustment.

100%

94eg!

iTrader: (2)

Yup, just adjust it to add a bit more free play in the pedal and you will be fine.