just got new front brake pads installed, but having a problem!!!

[pureform]

hello all,

I just got some new brake pads installed today on my '03 P5. After the installation the guy said to pump the brakes so I did while the car was off, they tensed up, but then when I turned the car on the pressure went away and the pedal is pretty "soft". I pumped the brakes more, and they seemed to be a little better, but never really got the pressure back. It's not totally going to the floor, but taking more than normal to stop the car when it should not take much force on the pedal to slow down/stop. Not sure if I screwed something up when pumping the brakes with the car off or if the pads just need some more time to break in. The brakes didn't require that much pressure to stop even with the worn out pads, so something is def wrong. I was under the impression that just changing pads wouldn't require the lines to be bled, am I right??

I'm not going to drive the car until I figure out what the deal is, so any suggestions or similar experiences with this would be greatly appreciated!! Thank you so much in advance for your input.

 

[dandan2]

bad master cylender?

 

[dandan2]

try bleeding the system and see if that helps. u could just have air in the lines.

 

[pureform]

I considered that, but I hadn't ever had any problems with the braking system previously..they were working fine even though the pads were worn til just after I got the new pads in...could something have happened to the master cylinder just from changing out the pads??

 

[pureform]

ok I here ya on the bleeding, is that pretty easy to do myself(with help)?? Have never bled brake lines before, I'm sure there's got to be a tutorial or thread on here.
thanks!

 

[1slowp5]

Yeah, try bleeding the brakes first.

 

[dandan2]

u need a helper, u have someone pump the brake pedal 3 or so times until the pedal is hard, then u open the bleeder valve on the caliper (make sure they keep pressure on the brake pedal and keep it to the floor until u close the valve, if u fail to close the valve before they lift their foot up it will allow more air to enter the system). blead the brake a few times per caliper to make sure there is a steady stream of fluid coming out and no air. also top off brake fluid when needed.

 

[pureform]

great advice, thank u dandan2

 

[CheeseHelmet]

If you had them installed by someone you should get them to bleed the brakes for you, it was very unsafe and unprofessional of them to send you on your way with a mushy brake pedal. If you don't trust them then by all means do it yourself, but they shouldn't be charging you for something that they were supposed to do.

 

[dandan2]

oh wait, if u had a shop install these pads they need to fix the problem.

 

[flash75]

I agree with getting the guy that did the work fix the problem.

That said, it shouldn't be necessary to bleed brakes when the pads are changed.
nothing is done during a routine pad change that will introduce air into the system.

There is no harm done to power brake systems when they are pumped with the
engine off. It's normal for them to build up when pumped and they will drop down
when the engine is started. It's also normal for new pads to feel soft/spongy until
they are bedded in. However the pedal shouldn't go near the floor to stop the car.

Although it's not necassary to bleed the brakes when changing pads it's a good
idea to replace the brake fluid when the pads are changed. Brake fluid collects
enough moisture in several years to considerably reduce brake performance. I
recently changed my brake pads plus I replaced the fluid as I have done every
two years.

Clifton

 

[pureform]

thanks again for the advice y'all...I drove around my neighborhood today a bit..and they seemed a little better, but still a bit more play than I'm used to. Hopefully it's just a bedding issue and will resolve as the pads break in. I didn't get the job done at a shop, there is a guy in town that changes out brake pads for $25/axle, so I only paid him to just switch out the pads...he was a nice enough guy and legit, I should have gone back and had him look at it again, but was in kind of a hurry and its not like the brakes weren't working at all, just seemed like too much play in them. He guarantees his work and I'm sure will help me out if a problem persists.
I think I will definitely change out the brake fluid though as suggested for safe measure. fun stuff
thanks

 

[kudakev615]

quick question.....the very first time you hit the brake pedal to pump it up, did you push it all the way to the floor? if so, you more the likely damaged the seals in the master cylinder. with no pressure in the brake system the pedal is allowed to travel MUCH further then normal. the the seals in the master cylinder traveled past where they usually operate and got damaged.

another question is when he pressed the piston back into the caliper, did he open up the bleeder screw and/or take the master cylinder cap off? by no doing either/or you can damage hydraulic valves and abs modules. they are used to having fluid moved in one direction. you start pushing fluid in there opposite direction you can get brake valves clogged up, blow out master cylinder seals, ect.

 

[pureform]

kudakev...I don't completely recall, but pretty sure I didn't push the pedal all the way to the floor and I am absolutely certain that he didn't touch the bleeder screws or master cylinder cap, I was watching the whole time.

If I had in fact pumped the pedal too hard, would there be any visible signs of damaged seals at the master cylinder?? leaking, etc.?

thanks

 

[kudakev615]

the seals are internal on the master cylinder and you would not be able to visually tell. since no bleeder screws were opened you can rule out air in the system. if the pedal was fine before the pad slap then it sounds like there is a hydraulic problem/issue. id put money on that was the master cylinder was damaged and that the seals are bypassing fluid causing the soft/spongy brake pedal.

 

[P-Funk!]

^yep. He skipped step one: 'remove the brake reservoir cap'

 

[SoonP5ismine]

i had a bad piston in one of my rear calipers where under heavy break pedal pushing the fluid would drip slightly and then at the same time when i released the pedal air was being introduced to the brake line and about a month of that and my brakes were a bit softer than they should be. i doubt its the master cylinder there must be a leak somewhere in your brake lines/calipers.