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      11-04-2012, 01:12 PM   #1
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major scare after replacing brake pads!

Last night I recently replaced my front brake with the new oem front pads. Everything went smooth enough but when I was going for the test run, I hit the brake pedal just to have it sink to the floor! I freaked out, who wouldn't going at 45 with a stop coming up soon, and I had to pump the brakes a few times to actually stop. Scared out of my mind, I pulled over, inspected the brakes some more and went back home. Has anyone had these problems???
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      11-04-2012, 01:27 PM   #2
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Was it your first brake application after changing the pads? You should have pumped the brakes before driving to push fluid back into the calipers and push the pads against the rotor before driving.

If you bled your brakes, then you might have air bubbles. Bleed again.
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      11-04-2012, 01:41 PM   #3
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Was it your first brake application after changing the pads? You should have pumped the brakes before driving to push fluid back into the calipers and push the pads against the rotor before driving.

If you bled your brakes, then you might have air bubbles. Bleed again.
I pumped the brakes for about 5 minutes before actually hitting the road, the first time turning the car on led to the pedal sinking as well but then turned back to normal. I didn't bleed my brakes but I feel like I might need to if this problem persists
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Originally Posted by The HACK View Post
I'm going to use a very simple analogy, I hope you'll understand.
Driving is like having sex.
It really is. You can read up all you want about how to please a woman, you can look at all the diagrams in the world, but just like the clitoris, you won't know what the hell an apex is before you actually find it.
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      11-04-2012, 04:04 PM   #4
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Not a pleasant experience! Did you pump the brakes with the engine running before taking to the road? It should only require a few pump actions of the brake pedal to restore positive (normal) pressure, certainly not require 5 minutes of pumping. When last have you checked your brake fluid level?
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      11-04-2012, 05:43 PM   #5
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Not a pleasant experience! Did you pump the brakes with the engine running before taking to the road? It should only require a few pump actions of the brake pedal to restore positive (normal) pressure, certainly not require 5 minutes of pumping. When last have you checked your brake fluid level?
I pumped it before and after turning the car on, I also checked the brake fluid level prior to taking it on the road but it wasn't a pleasant experience for sure, it also made me piss my pants lol I honestly thought I was going to slam into the car in front of me and luckily, I was able to stop in time
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I'm going to use a very simple analogy, I hope you'll understand.
Driving is like having sex.
It really is. You can read up all you want about how to please a woman, you can look at all the diagrams in the world, but just like the clitoris, you won't know what the hell an apex is before you actually find it.
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      11-05-2012, 10:35 AM   #6
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Quote:
Originally Posted by kiwi29 View Post
I pumped the brakes for about 5 minutes before actually hitting the road, the first time turning the car on led to the pedal sinking as well but then turned back to normal. I didn't bleed my brakes but I feel like I might need to if this problem persists

You know what to do.
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      11-05-2012, 03:19 PM   #7
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Originally Posted by CALWATERBOY View Post
You know what to do.
When I changed my pads last time I didnt have to bleed the brake system. Why would it happen now?
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      11-05-2012, 03:40 PM   #8
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Do you think that possibly the pads were binding up when you first tried to seat them after the install and didn't seat all the way, and then when you finally got on them on the road, the slipped and seated all the way? Because it doesn't sounds like a fluid issue since you did not open the bleeder valve during the install.

But its never a bad idea to bleed anyway.
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      11-05-2012, 03:45 PM   #9
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You need to bleed your brakes everytime you change pads... lol! There should not be any air in your fluid... your pedal sinked becoz of the air pockets in your fluid... you should bleed them out or it is going to happen again...
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      11-05-2012, 03:59 PM   #10
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Quote:
Originally Posted by crzylildude View Post
You need to bleed your brakes everytime you change pads... lol! There should not be any air in your fluid... your pedal sinked becoz of the air pockets in your fluid... you should bleed them out or it is going to happen again...
Really? Is it because I depressed the pads so its throwing air back into the line?

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Originally Posted by raceyBMW View Post
Do you think that possibly the pads were binding up when you first tried to seat them after the install and didn't seat all the way, and then when you finally got on them on the road, the slipped and seated all the way? Because it doesn't sounds like a fluid issue since you did not open the bleeder valve during the install.

But its never a bad idea to bleed anyway.
Hmmm that might be it I'm not sure, I did a full bedding procedure last night and the brakes felt slightly better. Maybe I need to redo it again tonight and hopefully it gets better. But the brakes might've taken time to seat but the pedal isn't sinking as bad as it was before
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I'm going to use a very simple analogy, I hope you'll understand.
Driving is like having sex.
It really is. You can read up all you want about how to please a woman, you can look at all the diagrams in the world, but just like the clitoris, you won't know what the hell an apex is before you actually find it.
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      11-05-2012, 04:16 PM   #11
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Quote:
Originally Posted by crzylildude View Post
You need to bleed your brakes everytime you change pads
Why? How would air enter the system in a typical pad change where you're not opening up the caliper?

Not that it'd ever hurt to bleed the system and pull out any contaminants that might be in the cylinders, but I'm curious as to your claim that one needs to do so every time you change pads. Is there something special about BMW's that's different from all the other marques?


kiwi29: whats your pedal feel like now? Your experiences sounds a LOT like raceyBMW's suggestion. If everything is normal now, that might have been it. If you still have a soft pedal then something's up with the system and it's time to bleed if for no reason but to eliminate that possibility.
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      11-05-2012, 04:54 PM   #12
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If it were me, I would take the wheels off again just for peace of mind, and make sure that the pads are all seated in the caliper housing correctly. Its a pain, but can't be too safe when it comes to the brakes, especially if you suspect something is up.
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      11-05-2012, 05:38 PM   #13
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Air does not get into your brake system just because you replaced the pads....
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      11-05-2012, 06:48 PM   #14
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Maybe OP opened up the brake fluid reservoir so he can depress the pistons? It will bubble up on the reservoir if you do that... or maybe clogged brake lines...

This typically happens when you install new pads but not always... It is safer to Bleed and Bed your brakes...

Last edited by crzylildude; 11-05-2012 at 06:58 PM.
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      11-05-2012, 08:55 PM   #15
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Quote:
Originally Posted by gtaccord View Post
Air does not get into your brake system just because you replaced the pads....
I thought it was possible because I had the caliper hanging a bit lower than normal and maybe it opened an air leak
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Originally Posted by raceyBMW View Post
If it were me, I would take the wheels off again just for peace of mind, and make sure that the pads are all seated in the caliper housing correctly. Its a pain, but can't be too safe when it comes to the brakes, especially if you suspect something is up.
I plan on doing that tomorrow and hopefully I don't find any kinks
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Originally Posted by gpb View Post
Why? How would air enter the system in a typical pad change where you're not opening up the caliper?

Not that it'd ever hurt to bleed the system and pull out any contaminants that might be in the cylinders, but I'm curious as to your claim that one needs to do so every time you change pads. Is there something special about BMW's that's different from all the other marques?


kiwi29: whats your pedal feel like now? Your experiences sounds a LOT like raceyBMW's suggestion. If everything is normal now, that might have been it. If you still have a soft pedal then something's up with the system and it's time to bleed if for no reason but to eliminate that possibility.
I have been taking his advice and it actually helped a lot
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Originally Posted by crzylildude View Post
Maybe OP opened up the brake fluid reservoir so he can depress the pistons? It will bubble up on the reservoir if you do that... or maybe clogged brake lines...

This typically happens when you install new pads but not always... It is safer to Bleed and Bed your brakes...
I never opened the reservoir when I depressed the pistons, I figured I should've though, I might need to bleed the brake system again
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I'm going to use a very simple analogy, I hope you'll understand.
Driving is like having sex.
It really is. You can read up all you want about how to please a woman, you can look at all the diagrams in the world, but just like the clitoris, you won't know what the hell an apex is before you actually find it.
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      11-05-2012, 09:20 PM   #16
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Bleed the brakes and you are fine.

Dont ask why you need to, but a bleed ofter a pad change is just a good idea.
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      11-05-2012, 09:43 PM   #17
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Air does not get into your brake system just because you replaced the pads....
truth.
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      11-06-2012, 12:15 AM   #18
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Bleed the brakes and you are fine.

Dont ask why you need to, but a bleed ofter a pad change is just a good idea.
No questions here lol I'm gonna just need an extra set of hands and about a few hours lol
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truth.
I just thought maybe because I compressed the piston again that it would've pushed air into the reservoir ? Would that be possible?
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I'm going to use a very simple analogy, I hope you'll understand.
Driving is like having sex.
It really is. You can read up all you want about how to please a woman, you can look at all the diagrams in the world, but just like the clitoris, you won't know what the hell an apex is before you actually find it.
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      11-06-2012, 04:07 AM   #19
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Well, I can see a ton of mechanics making $$ for nothin here - NEVER in my life have I heard that you need to bleed your brakes after a pad change & it is definitely not necessary...


> Only time you need to bleed brakes is if the system has been opened to the air, such as disconnecting a brake line, or replacing a master cylinder/caliper, etc.

> And opening up the cap on your reservoir doesn't introduce air into the system either (unless you have no fluid in there and pump the pedal).


I've been changing my own pads, on more different cars that I have owned, than I can remember, since 1976 & have NEVER bled the brakes after simple pad change.


> If the brakes didn't need bled before the change, they don't after. It isn't even needed as routine maintenance - if there is no air leak in your system there is no way for the air to enter.

> Now, I agree that brake system needs to be completely flushed/refilled with fresh fluid every 2 yrs - but this is only to refresh the fluid which can/will absorb water over time.


> Pushing the caliper piston back in to housing to allow for new thicker pads does not let air into the system - the piston is sealed in bore. If moving the piston added air - then every time you use the brakes air would enter.

> Air in your system does not result in your pedal going to the floor either. Air in the system gives you a 'spongy' feel when you apply the brakes - as air is not compressible in a hydraulic system.

> Pads that are not 'bedded in' don't result in pedal going to floor either. Bedding in simply transfers pad material to the rotor (if done correctly) to enhance braking ability. Mostly this is done with aftermarket hi performance pads - not OEM. Hell, there are tons of pads being changed every day by dealers (including BMW), or ind. shops that are never bedded in. They change your brakes - you pay - get in the car & drive off. All (4) of my rotors/pads have been changed under warranty with OEM, nary a mention on needing bedded in, and brake performance is as when new.

As mentioned, you always start car, pump up brakes after a pad change - simply to move piston/pad combo back out into contact with rotor after you have retracted the piston fully during swap. This should take like 3-5 pumps on the pedal max, not 5 minutes of pumping.

If it took you 5 min to get any pedal feel, and then they still weren't good upon 1st use - then you have problems other than what can be fixed by a simple pad change.
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      11-06-2012, 04:46 AM   #20
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All correct.

Quote:
Originally Posted by 1QuikWS6 View Post
Well, I can see a ton of mechanics making $$ for nothin here - NEVER in my life have I heard that you need to bleed your brakes after a pad change & it is definitely not necessary...


> Only time you need to bleed brakes is if the system has been opened to the air, such as diconecting a brake line, or replacing a master cylinder/caliper, etc.

> And opening up the cap on your reservoir doesn't introduce air into the system either (unless you have no fluid in there and pump the pedal).


I've been changing my own pads, on more different cars that I have owned, than I can remember, since 1976 & have NEVER bled the brakes after simple pad change.


> If the brakes didn't need bled before the change, they don't after. It isn't even needed as routine maintenance - if there is no air leak in your system there is no way for the air to enter.

> Now, I agree that brake system needs to be completely flushed/refilled with fresh fluid every 2 yrs - but this is only to refresh the fluid which can/will absorb water over time.


> Pushing the caliper piston back in to housing to allow for new thicker pads does not let air into the system - the piston is sealed in bore. If moving the piston added air - then every time you use the brakes air would enter.

> Air in your system does not result in your pedal going to the floor either. Air in the system gives you a 'spongy' feel when you apply the brakes - as air is not compressible in a hydraulic system.

> Pads that are not 'bedded in' don't result in pedal going to floor either. Bedding in simply transfers pad material to the rotor (if done correctly) to enhance braking ability. Mostly this is done with aftermarket hi performance pads - not OEM. Hell, there are tons of pads being changed every day by dealers (including BMW), or ind. shops that are never bedded in. They change your brakes - you pay - get in the car & drive off. All (4) of my rotors/pads have been changed under warranty with OEM, nary a mention on needing bedded in, and brake performance is as when new.

As mentioned, you always start car, pump up brakes after a pad change - simply to move piston/pad combo back out into contact with rotor after you have retracted the piston fully during swap. This should take like 3-5 pumps on the pedal max, not 5 minutes of pumping.

If it took you 5 min to get any pedal feel, and then they still weren't good upon 1st use - then you have problems other than what can be fixed by a simple pad change.
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      11-06-2012, 11:55 AM   #21
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Quote:
Originally Posted by 1QuikWS6 View Post
Well, I can see a ton of mechanics making $$ for nothin here - NEVER in my life have I heard that you need to bleed your brakes after a pad change & it is definitely not necessary...


> Only time you need to bleed brakes is if the system has been opened to the air, such as disconnecting a brake line, or replacing a master cylinder/caliper, etc.

> And opening up the cap on your reservoir doesn't introduce air into the system either (unless you have no fluid in there and pump the pedal).


I've been changing my own pads, on more different cars that I have owned, than I can remember, since 1976 & have NEVER bled the brakes after simple pad change.


> If the brakes didn't need bled before the change, they don't after. It isn't even needed as routine maintenance - if there is no air leak in your system there is no way for the air to enter.

> Now, I agree that brake system needs to be completely flushed/refilled with fresh fluid every 2 yrs - but this is only to refresh the fluid which can/will absorb water over time.


> Pushing the caliper piston back in to housing to allow for new thicker pads does not let air into the system - the piston is sealed in bore. If moving the piston added air - then every time you use the brakes air would enter.

> Air in your system does not result in your pedal going to the floor either. Air in the system gives you a 'spongy' feel when you apply the brakes - as air is not compressible in a hydraulic system.

> Pads that are not 'bedded in' don't result in pedal going to floor either. Bedding in simply transfers pad material to the rotor (if done correctly) to enhance braking ability. Mostly this is done with aftermarket hi performance pads - not OEM. Hell, there are tons of pads being changed every day by dealers (including BMW), or ind. shops that are never bedded in. They change your brakes - you pay - get in the car & drive off. All (4) of my rotors/pads have been changed under warranty with OEM, nary a mention on needing bedded in, and brake performance is as when new.

As mentioned, you always start car, pump up brakes after a pad change - simply to move piston/pad combo back out into contact with rotor after you have retracted the piston fully during swap. This should take like 3-5 pumps on the pedal max, not 5 minutes of pumping.

If it took you 5 min to get any pedal feel, and then they still weren't good upon 1st use - then you have problems other than what can be fixed by a simple pad change.
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All correct.
.
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