VS brakes weak after brake pad/rotor change

[Pickled]

I changed the front brake pads and 1 rotor on my mate's VS yesterday, one of the calipers fell apart and I had to push the middle part back in which caused him to lose a fair bit of brake fluid, after installing the new parts I topped up the brake fluid.

When using the brakes the brake pedal will go to the floor and take ages to slow the car down, what seems to be the issue? Did I accidentally knock a line or something? The brake fluid is filled to the max.

Thank you

[Brett_jjj]

They probably need bleeding to get the air out.Air probably got into the system somewhere when the caliper fell apart...The front and rear brake circuits are seperate systems and its probably just the rear brake circuit working at the moment because of air in the front system,and thats why it takes ages to slow down..be sure to first start the bleeding process at the caliper thats furtherest away from the master cylinder.

[Pickled]

Oh ok, how does one bleed the calipers?

[Brett_jjj]

Top up the master cylinder,then get someone to pump the brake pedal a few times and then hold it in.Whilst its held in,undo the bleeder screw a little bit on the caliper and let the air come out with the fluid,then tighten the bleeder screw again,then the person pumps up the brake pedal again a few times and you repeat this process until no more air comes out of the bleeder screw on the caliper,it should just have fluid coming out with no air bubbles in it once its bled properly.Its best to do all 4 calipers,but Id just do the front 2 for now,start at the passenger side caliper, and once its free of air,do the drivers sinde then..Make sure the brake pedal is not released whilst the bleeder screw is undone, or loose, as it will suck in more air,and make sure the master cylinder is kept full of brake fluid,otherwise air will be sucked into the system and it will all have to be bled again...I find 3 people make this job easy,one to pump the pedal,one to keep an eye on the master cylinder fluid level,and me, to do the actual bleeding...

[Hangman]

As above, but I gotta ask this.

If you don't know/aren't sure what your doing, why are you playing with brakes? They're sort of important if you want the car to stop...

[Brett_jjj]

A workshop manual is the go if you want to learn how to do your own services and repairs properly..Worth every cent I reckon..Ive been fixing cars for years now and I still use them all the time...

[Hangman]

Yeah, I wasn't saying don't have a go and I agree the manuals are worth it, but it's not like he's dodgin up a stereo or something. Brakes aren't something you want to fail due to lack of knowledge.

[acarmody]

Yeah, I wasn't saying don't have a go and I agree the manuals are worth it, but it's not like he's dodgin up a stereo or something. Brakes aren't something you want to fail due to lack of knowledge.

LOL, bad example, dodgy sound system can set you car on fire.

To the OP, maybe get a mechanic to look over that caliper that fell apart, I'm pretty sure they aren't supposed to do that, and any seals on it are probably way gone and it will now leak brake fluid, something you don't want on brake discs and pads.

[Pickled]

Thanks for all the advice everyone, just bled the brake system and it's running great.

As above, but I gotta ask this.

If you don't know/aren't sure what your doing, why are you playing with brakes? They're sort of important if you want the car to stop...

I've changed brake pads before and never had this problem so I'm not just 'playing' around with them, I have some idea of what I'm doing otherwise I wouldn't touch it.

[Hangman]

Sorry, but not knowing that if fluid comes out air gets in and then not knowing if/how to bleed it equates to playing round to me. Especially when it's not your car.

And calipers shouldn't fall apart...

LOL, bad example, dodgy sound system can set you car on fire.

Haha yeah bad example.

[Paul13pp]

Its a pretty good idea to change the brake fluid in the lines every few years.
I usually suck out most of the fluid in the reservoir, then top it up with new stuff and bleed the system pushing the new fluid through.

[Brett_jjj]

Yep,I change my brake fluid every time I fit new pads,probably every 8-12 months it works out at..keeps the brake system in good nick..

[Sabbath']

I've changed brake pads before and never had this problem so I'm not just 'playing' around with them, I have some idea of what I'm doing otherwise I wouldn't touch it.

Disagree. If you knew what you where doing, when you knocked the piston out you would have known that you had let air into a closed system and therefore it needed to be bled out. Instead of coming on here, asking for the cause of your trouble. And then asking how to actually bleed the brakes.

Seriously, dont touch your brakes if you dont know how to fix them back to how they were before you started messing around with them. It's not just your life you're playing with trying to be some kind of backyard DIY legend with your two adjustable spanners.

Jus' Sayin.

[Sabbath']

Yep,I change my brake fluid every time I fit new pads,probably every 8-12 months it works out at..keeps the brake system in good nick..

This is a good idea. You should be changing the fluid at an interval because it becomes hydroscopic (think that's the word) over time, from the moisture in the atmosphere and this reduces braking performance.

[a1k3m1]

i found that when your bleeding the brakes to connect a piece of fishtank air hose to the bleeder nipple, this way it makes alot less mess..

That is when you've figured out how to bleed the thing!! .. bad idea to play with them if you cant fix them properly!!!! =O

[RX25SE]

I've changed brake pads before and never had this problem so I'm not just 'playing' around with them, I have some idea of what I'm doing otherwise I wouldn't touch it.

Sounds to me like the piston fell out. If you had an idea of what you were doing, this would not have happened.
The fact that the pedal was going to the floor (apart from the air) can cause damage to the master cylinder.
If it was the piston that fell out, keep an eye on this caliper for leaks as the seal may have been damaged.


I agree with the above comments regarding working on brakes without an understanding of how the system works and basic precautions.

This is a good idea. You should be changing the fluid at an interval because it becomes hydroscopic (think that's the word) over time, from the moisture in the atmosphere and this reduces braking performance.

Brake fluid is hydroscopic as it absorbs moisture easily. As it absorbs moisture, the boiling point is reduced due to the fact water boils at 100deg and brake fluid at around 260deg.

[Pickled]

Disagree. If you knew what you where doing, when you knocked the piston out you would have known that you had let air into a closed system and therefore it needed to be bled out. Instead of coming on here, asking for the cause of your trouble. And then asking how to actually bleed the brakes.

Seriously, dont touch your brakes if you dont know how to fix them back to how they were before you started messing around with them. It's not just your life you're playing with trying to be some kind of backyard DIY legend with your two adjustable spanners.

Jus' Sayin.

I said I had a basic idea of what needed to be done, you only learn from experience and I've never had any life-threatening issues from doing so.

The car stayed in my drive-way and was not driven until the brakes were 100%, please don't assume you know everything when you clearly don't, it makes you look a bit silly mate.

And for the record I'd rather be a DIY legend then a forum hero which you have proved to be, if you're going to type in pretty capitals and full stops at least use it correctly.

I miss the way this forum used to be, where you could post a thread and not have Nazi's crawl all over it demanding blue eyes and blonde hair, I come on here for advice and not to get condemned for asking a simple question, there are still plenty of nice/helpful people on here don't get me wrong, but it's becoming a joke.

Just sayin'.

[monkeys437]

Mate, I made a royal Arseclown of myself the first time I changed pads and rotors. The upside is I now know how to change pads and rotors. You should definitely get a gregorys manual. Its only 30-40 bucks, which means it pays itself off really quickly compared to making mistakes

[TrikkBen]

If you are going to bleed brakes, start from the furthest point from the master cyl. (The rear left on a Commodore), then rear right, front left, front right. That way you won't be working air back through already bled lines.
Use clear tube over the bleed nipple into a container, as you open the nipple (after the pedal has been pumped and HELD) watch for breaks in the fluid, thats the air that makes the brakes spongy. Bleeding brakes is easy if you take your time and don't rush. Make sure you get into a pattern of PUMP, HOLD, OPEN, SHUT or else all your work is ruined and you will have to start again.

Also remember to fill the master cyl.

[Hangman]

As above, don't let the master cylinder run dry or you have to start over. Also doing it with the car running is easier.

[Sabbath']

I said I had a basic idea of what needed to be done, you only learn from experience and I've never had any life-threatening issues from doing so.

I'd say the pedal going to the floor could be a potentially life-threatening issue, so to say that you've never had any is incorrect.

The car stayed in my drive-way and was not driven until the brakes were 100%, please don't assume you know everything when you clearly don't, it makes you look a bit silly mate.

Basic theory is something you didnt have before you went into start this job. Otherwise you wouldnt have pushed the piston out of the caliper, and then wouldnt have assumed that the way to fix the problem was just adding the fluid that had come out after you messed up.

And for the record I'd rather be a DIY legend then a forum hero which you have proved to be, if you're going to type in pretty capitals and full stops at least use it correctly.

I dont see how pointing out your mistake makes me a forum hero, again, the whole issue here was YOUR inability to carry out the job you thought you were skilled enough to do, but obviously werent.

And atleast my punctuation and such doesnt have the ability to kill anyone.

I miss the way this forum used to be, where you could post a thread and not have Nazi's crawl all over it demanding blue eyes and blonde hair, I come on here for advice and not to get condemned for asking a simple question, there are still plenty of nice/helpful people on here don't get me wrong, but it's becoming a joke.

Just sayin'.

No need to get offended. You messed up, with the braking system on a car. Sorry that people arent handing you lollipop's and gold star's for effort. It doesnt work like that.

[Not_An_Abba_Fan]

Easy mistake for new players, I bet you removed both calipers and then pushed the piston in on one said and the other side popped out.

In future, do one side at a time and this will never happen.

[Pickled]

I'd say the pedal going to the floor could be a potentially life-threatening issue, so to say that you've never had any is incorrect.

It would have been if I drove the car, not when the car was sitting on jack stands in my driveway, genius.

Basic theory is something you didnt have before you went into start this job. Otherwise you wouldnt have pushed the piston out of the caliper, and then wouldnt have assumed that the way to fix the problem was just adding the fluid that had come out after you messed up.

I didn't push the piston out, it fell out, big difference. Yet again assuming makes you look like a moron.

I dont see how pointing out your mistake makes me a forum hero, again, the whole issue here was YOUR inability to carry out the job you thought you were skilled enough to do, but obviously werent.

No, it makes you a forum hero with nothing better to do than to cause trouble and kiss moderator's ass's in your free time. You could have easily just told me that I needed to bleed my system but no, that would be boring and too helpful for your liking.

And atleast my punctuation and such doesnt have the ability to kill anyone.

No need to get offended. You messed up, with the braking system on a car. Sorry that people arent handing you lollipop's and gold star's for effort. It doesnt work like that.

If you spent more time actually reading threads and not racing to the bottom of the page to reply and try to look like a funny guy you would know what's going on, I didn't mess up I just didn't know it had to be bled, but now I do, and no one was injured or killed in the process.

Thanks for the entertainment cupcake, and thanks for allowing me to make yet another JC forum hero look like a jackass, ciao.

[ari666]

I didn't push the piston out, it fell out, big difference. Yet again assuming makes you look like a moron.

in between tears of laughter, i managed to read this bit clearly....


how, oh how the feck does a piston "fall out"???? the appriopriate way of approaching this thread would be

hi all. i was playing with a mates car, and have no idea what i was doing. my mate stomped on the brake pedal while the caliper was off and it pushed the piston out. rather than going any further and potentially causing a major accident and hundreds of dollars worth of damage to my mates car, i stopped pretending i knew what i was doing and am now asking for advice

[Sabbath']

It would have been if I drove the car, not when the car was sitting on jack stands in my driveway, genius.

Wonder what your mate thought after he had to leave his car sitting there because his cluey mate left his car undrivable. Maybe that's why you're so sore about people telling you you're wrong for doing the wrong thing. It's ok. It's the internet. I dont take this personally, so you can come in here and tell me you did nothing wrong all you like to validate your feelings. Because at the end, we both know that it wasnt me who knocked the piston out and tried to fix it by just topping the fluid up.

I didn't push the piston out, it fell out, big difference. Yet again assuming makes you look like a moron.

Interesing...it "fell" out. Most likely you did exactly what NAAF said. Had both sides off and got gung-ho with the multi-grips or clamp and pushed the piston out on the opposite side. Just for future reference, as NAAF said, do it one side at a time, or get some line clamps for the hose to stop the fluid flow.

No, it makes you a forum hero with nothing better to do than to cause trouble and kiss moderator's ass's in your free time. You could have easily just told me that I needed to bleed my system but no, that would be boring and too helpful for your liking.

You'd already been told you needed to bleed the braking system. I didnt see it as being needed for me to get on here and just post that you needed to bleed the system. I posted because of your statement that you werent just playing around and that you knew what you were doing when the mere creation of this thread proves otherwise.

If you spent more time actually reading threads and not racing to the bottom of the page to reply and try to look like a funny guy you would know what's going on, I didn't mess up I just didn't know it had to be bled, but now I do, and no one was injured or killed in the process.

Thanks for the entertainment cupcake, and thanks for allowing me to make yet another JC forum hero look like a jackass, ciao.

I wasnt trying to be funny at all. I dont find it funny when people think they know what they're doing and try to fix parts of cars, vital parts of the car like the braking system moreso, and then get it wrong which has the possibility to kill or injure people.