[Arexander]

Hey guys,


My rear brakes have worn down, so I decided to save some money and replace the pads and rotors myself. I decided to ask my wife to get me all the rear brake components since she gets some discounts at BMW.

The DIY articles, explanations and videos made it seem so simple. It wasn't until I realized that every article and every video did not cover all the angles to the installation.

My issue:

I was hammering away at the p.o.s rotor that was not coming off. Finally, when I got it off, I replaced it with the new one. Then, I tackled the pads.

The first article I read didn't say anything about compressing the piston. Instead, the picture description said, "Now, take off the pads." I took the outer one with no issue.

Then, in my attempt to take off the inner pad, I didn't notice it had metal prongs (behind the pad) to hold it securely into the piston. The stupid article said, "Don't worry, usually the inner pad takes some strength to take it off." Well, as I pulled it harder, the piston popped right out with the brake pad, and the brake fluid slowly came pouring out. "Oh sh!t!!!"

I quickly looked at the rubber boot and, thankfully, I didn't see anything torn/ripped. I looked up another article, and low and behold, "Use the old pad with a C-Clamp and compress the piston back. BE CAREFUL to pull the pad out as there are metal prongs behind it holding into the piston."

I carefully put the piston back into the rubber seal/boot to make sure to not rip it. Once I got the piston back in, I saw no more leaking. I put the old pad into the piston and compressed the piston back into place with a C-Clamp. This time, I re-assembled the caliper by putting the pads in correctly. Made sure I didn't see any leaks. Put the caliper back on to the rotor and looked several hours later to make sure there were no leaks.

So, this afternoon, I curiously searched for any related articles to my issue. I couldn't find anything directed to BMW's, however, people had this same issue on other cars. The consensus: many of the people advised to either get a "replacement kit" (new piston) or buy a re-manufactured caliper.

I asked my wife to order me #13:



What do you guys recommend? Am I okay as is? Or should I be cautious as this could become a serious issue down the road?

Thanks for your help!

[feuer]

If is not leaking just bleed the brake system and let it be. Regarding DIY articles and videos online often they are incomplete. Sometimes even incorrect. My general opinion is to consult these articles and videos and tackle the matter only if you have done same or similar job on a different vehicle.

[Arexander]

Originally Posted by feuer

If is not leaking just bleed the brake system and let it be. Regarding DIY articles and videos online often they are incomplete. Sometimes even incorrect. My general opinion is to consult these articles and videos and tackle the matter only if you have done same or similar job on a different vehicle.

Thanks for the input here. I usually like to research multiple articles, forums, and videos before I decide to attempt a repair or do a modification to my car. Once I feel comfortable, I tackle it. That's only because of all the research I've done makes me familiar with every component I am looking at.

In this case, each article was so straight forward that I deemed it simple. Until I got into it, I started seeing all these little inconsistencies that weren't even mentioned. One person removed the plate from the caliper, another removed the entire caliper. Others had the caliper dangling; whereas, others had it zip tied or on top of a paint bucket.

It was just frustrating that there were a lot of things not mentioned or simply missing. I'm at the point where I'd like to make a thorough DIY for rotor and pad change.

[feuer]

Like I said online articles and videos are incomplete and often plain wrong but they are still meant for people that have some kind of experience in matter thus a lot of details omitted, different aproaches and etc because they expect the viewer is familiar with the job already. Let's put it this way: no YouTube video will help you overhaul your engine! As simple as that. It can only help you overhaul your engine, this particular engine, if you have some engine rebuilding back round. I'm glad the brake job worked out! If you make a good, complete and correct DIY on brakes we could as the moderators to make it a sticky.

[Arexander]

Originally Posted by feuer

If is not leaking just bleed the brake system and let it be. Regarding DIY articles and videos online often they are incomplete. Sometimes even incorrect. My general opinion is to consult these articles and videos and tackle the matter only if you have done same or similar job on a different vehicle.

So the consensus here is to bleed (flush) out the brake fluid?

I finally assembled everything, but now my brake pedal is going down to the floor.

I was searching on DIYs and general articles to flush out the brake fluid, but it seems like I need other items to do this. I wish a simple top off of brake fluid and a couple of pumps on the break would be sufficient... is it this easy?

[feuer]

Originally Posted by Arexniba

So the consensus here is to bleed (flush) out the brake fluid?
I finally assembled everything, but now my brake pedal is going down to the floor.
I was searching on DIYs and general articles to flush out the brake fluid, but it seems like I need other items to do this. I wish a simple top off of brake fluid and a couple of pumps on the break would be sufficient... is it this easy?

Yes, you can top off the brake canister with brake fluid and pump the pedal. You will need a helper for this. Start with right rear, then left rear, then right front and lastly left front. Do it first with engine off then second time with engine on.

[Arexander]

Originally Posted by feuer

Yes, you can top off the brake canister with brake fluid and pump the pedal. You will need a helper for this. Start with right rear, then left rear, then right front and lastly left front. Do it first with engine off then second time with engine on.

Thank you for all your guidance here. It's really appreciated. I guess I could ask my wife. She can pump the brake while I top the canister.

I hope you don't mind if I PM you for more explanation(s) if I can't find any researching?

[e90Jeet]

Hey, I'll be changing break pads, rotors and sensor (rear) this weekend. Do I need to take care of fluid? I got the break fluid flushed last weekend by dealer. And they recommended to change break pads (3mm left) but asking $$$ so decided to do myself.

anything else do I need to take care of apart from hardware installation? One thing is sure to apply break lub before installing any parts. Appreciate your help.

[Arexander]

Originally Posted by e90Jeet

Hey, I'll be changing break pads, rotors and sensor (rear) this weekend. Do I need to take care of fluid? I got the break fluid flushed last weekend by dealer. And they recommended to change break pads (3mm left) but asking $$$ so decided to do myself.

anything else do I need to take care of apart from hardware installation? One thing is sure to apply break lub before installing any parts. Appreciate your help.

Hey there. This was one of the reasons I got frustrated with the research I had done. Simple answer--yes.

Technically, you will need to bleed your brakes when you're done installing all your brake pads (and rotors?). I saw some threads where people changed their pads only, then had to bleed their brakes because they introduced air into their brake lines.

My suggestion, if you have the time, then do it. If you're somewhat a novice at working on cars, then do it. If none of the above, but you still want to do it, make sure you have an extra car. Or work/school isn't too far to take an uber. Lol

So far, I've spent around $600-$700 on brake parts (whole sale prices through my wife, and the necessary tools to work on this job. I did it to "save money," but I wish I hadn't lol. On the bright side, I've learned to replace the brakes and rotors. I wish I had done it on a weekend knowing now that there's more to just swapping out the rotors and pads.

[ATLIEN]

Originally Posted by e90Jeet

Hey, I'll be changing break pads, rotors and sensor (rear) this weekend. Do I need to take care of fluid? I got the break fluid flushed last weekend by dealer. And they recommended to change break pads (3mm left) but asking $$$ so decided to do myself.

anything else do I need to take care of apart from hardware installation? One thing is sure to apply break lub before installing any parts. Appreciate your help.

If you got the fluid flushed last weekend then there is really no need to do it again. I would, however, get a clean container and a turkey baster or other suction device and pull a little brake fluid out of the reservoir so that when you compress your piston that it does not overflow from your reservoir. I would recommend watching the brake job video on youtube from Bavauto and you should be all set.

[davidwarren]

Hey OP- you really shouldn't have been able to just pull the piston out of the caliper. There are two scenarios that come to mind- 1) your pad was seriously corroded/seized inside the piston. Did you have to exert Herculean strength to pull it out? or 2) you have a leak somewhere that let air in and made it much easier to pull the piston out. I would buy a new piston seal and rebuild that caliper. However, given your prior experience, I would consider a reman'd caliper. They are cheap. Any yes, you'll have to bleed the fluid to get the air out.

[Arexander]

Originally Posted by davidwarren

Hey OP- you really shouldn't have been able to just pull the piston out of the caliper. There are two scenarios that come to mind- 1) your pad was seriously corroded/seized inside the piston. Did you have to exert Herculean strength to pull it out? or 2) you have a leak somewhere that let air in and made it much easier to pull the piston out. I would buy a new piston seal and rebuild that caliper. However, given your prior experience, I would consider a reman'd caliper. They are cheap. Any yes, you'll have to bleed the fluid to get the air out.

1. I felt a surge of power, and with the fury of a 1,000 angry puppies, I pulled out the pad with the piston!

2. Prior to replacing the rotor now, I cannot confirm who did the rears. I purchased my car used 3 years ago. Since then, I've only had the fronts done. My sensor for the rears just came on last week.

In regards to your advice(s), do you mean part # 13 in my original post? My wife got me the part, and I am considering replacing it. I've already gotten this far and looked through detailed articles and videos on this. It doesn't look complex. Then again, the more I look at the pictures that the people posted, I noted that the seal guard wasn't damaged--torn, ripped, etc.

Looked at this guide as a reference: http://www.bmwforums.info/general-gu...-calipers.html

I will bleed the brakes to see if that piston is leaking.

[davidwarren]

Originally Posted by Arexniba

1. I felt a surge of power, and with the fury of a 1,000 angry puppies, I pulled out the pad with the piston!

2. Prior to replacing the rotor now, I cannot confirm who did the rears. I purchased my car used 3 years ago. Since then, I've only had the fronts done. My sensor for the rears just came on last week.

In regards to your advice(s), do you mean part # 13 in my original post? My wife got me the part, and I am considering replacing it. I've already gotten this far and looked through detailed articles and videos on this. It doesn't look complex. Then again, the more I look at the pictures that the people posted, I noted that the seal guard wasn't damaged--torn, ripped, etc.

Looked at this guide as a reference: http://www.bmwforums.info/general-gu...-calipers.html

I will bleed the brakes to see if that piston is leaking.

I mean, you could rebuild it, but I would (and have) just buy a remanufactured caliper. https://www.turnermotorsport.com/p-3...xi-335is-335d/

I've had my calipers rebuilt by my shop before, and it was about the same price as buying remanufactured calipers.

But first I would just check and see if your current calipers are ok. If they feel ok and are not leaking, they are probably fine. Just unusual to hear someone pull the entire piston out when replacing pads.

[mweisdorfer]

Wow...

I have never seen or heard of a piston coming out as a result of the inner pad being stuck (frozen) inside the piston.

This experience is certainly an anomaly to be sure.

More often then not, you can get a Brake job done in all four brakes for $500.00 in parts.

You'll need to research on how to put the rubber seal back on the piston and then put the seal and piston back on the caliper. It can be a PITA.

PVC pipe, at the right diameter, with a "little love" could be "the ticket".

Hindsight 20/20, a little Kroil Oil would have done the trick.

[mweisdorfer]

Wow...

I have never seen or heard of a piston coming out as a result of the inner pad being stuck (frozen) inside the piston.

This experience is certainly an anomaly to be sure.

More often then not, you can get a Brake job done in all four brakes for $500.00 in parts.

You'll need to research on how to put the rubber seal back on the piston and then put the seal and piston back on the caliper. It can be a PITA.

PVC pipe, at the right diameter, with a "little love" could be "the ticket".

Hindsight 20/20, a little Kroil Oil would have done the trick.

[mweisdorfer]

Wow...

I have never seen or heard of a piston coming out as a result of the inner pad being stuck (frozen) inside the piston.

This experience is certainly an anomaly to be sure.

More often then not, you can get a Brake job done in all four brakes for $500.00 in parts.

You'll need to research on how to put the rubber seal back on the piston and then put the seal and piston back on the caliper. It can be a PITA.

PVC pipe, at the right diameter, with a "little love" could be "the ticket".

Hindsight 20/20, a little Kroil Oil would have done the trick.

[mweisdorfer]

Wow...

I have never seen or heard of a piston coming out as a result of the inner pad being stuck (frozen) inside the piston.

This experience is certainly an anomaly to be sure.

More often then not, you can get a Brake job done in all four brakes for $500.00 in parts.

You'll need to research on how to put the rubber seal back on the piston and then put the seal and piston back on the caliper. It can be a PITA.

PVC pipe, at the right diameter, with a "little love" could be "the ticket".

Hindsight 20/20, a little Kroil Oil would have done the trick.

[Arexander]

Originally Posted by mweisdorfer

Wow...

I have never seen or heard of a piston coming out as a result of the inner pad being stuck (frozen) inside the piston.

This experience is certainly an anomaly to be sure.

More often then not, you can get a Brake job done in all four brakes for $500.00 in parts.

You'll need to research on how to put the rubber seal back on the piston and then put the seal and piston back on the caliper. It can be a PITA.

PVC pipe, at the right diameter, with a "little love" could be "the ticket".

Hindsight 20/20, a little Kroil Oil would have done the trick.

Thank you for the advice here. I joke around and say a lot of random shit happens in my life that doesn't normally happen to a lot of people. It seems that I'm keeping that credibility even with this situation that happened--pad coming off with the piston. Then again, I found a high number of search results when I typed in "brake pad and piston popped out." lol

I didn't finish the driver's side brake pads yet. Funny thing is that the bad popped out this time without the piston popping out. I followed the exact same process too. lol

Once the pads go in tonight, I'll start the bleeding process. Pray for me

[Arexander]

Hey guys. Update here.

Finally! Installed the pads and rotors on the rear. The wifey helped me with bleeding the brakes. Did all sides as recommended (passenger rear, driver rear, passenger front, and driver front). No leaks nor air bubbles.

Double checked that all bolts were securely fastened and put the wheels back on at torque specs.

Asked the wifey to follow me in her car. We both notice (heard) that there was this "metallic" sound when driving or braking.

I put the grease behind the pads. Is this normal? I saw the recommended break ins--drive for 15-30 minutes and gentle stops (no hard braking).

I'm inclined to take it to a mechanic local to do a quick inspection.

Any thoughts?

[Arexander]

Update:

Fixed!

Took it to a nearby mechanic. I did a pretty good job being my first time on brakes. The grinding was due to the dust pan/dust guard/back plate.

Piston wasn't affected, but as someone pointed out, "An anomaly that piston came off with brake pad."

Thanks everyone for your input during this project.

[juld0zer]

Or your pads were extremely worn, like both pads on the same caliper were worn to metal. Then the piston would've been teetering near the seal. Add a rusted pad and i think you have a situation there. There's a reason BMW cites 3mm as the minimum pad thickness. Applying brake grease to the backs of the pads where they contact the piston and caliper is also recommended to prevent the pad glueing itself together.

Sounds like you got away with it fine
The hardest part of doing rear pads is the loctited carrier bolts.

[Arexander]

Originally Posted by juld0zer

Or your pads were extremely worn, like both pads on the same caliper were worn to metal. Then the piston would've been teetering near the seal. Add a rusted pad and i think you have a situation there. There's a reason BMW cites 3mm as the minimum pad thickness. Applying brake grease to the backs of the pads where they contact the piston and caliper is also recommended to prevent the pad glueing itself together.

Sounds like you got away with it fine
The hardest part of doing rear pads is the loctited carrier bolts.

I'm getting down to religion here, and believe that my anomaly was a miracle! Lol. I commute about 100mi a day to work and I've experienced no issues. However, I've been inspecting them to make sure there's no leaks.

You're right, I believe the pads were down to nothing. I had passed almost -5k miles on them.