[SD Convert]

Originally Posted by Daggers

Firstly, open the bonnet and remove the trim covering the brake servo. Photos show a RHD car but the same applies for LHD car. The trim is held in by three 10mm bolts that simply need a quarter turn to unlock. Once the trim is removed, undo the brake fluid cap - this is so when you push the calipers pots back into the caliper later, it’s easier for the fluid to move back through the brake lines.

...

You'll need to push the caliper pots back into the caliper - there's a 'proper' tool for this (called a caliper rewind tool), but given how much it costs, and how easy it is to push them back in by hand if you're careful, that's the way to go in my opinion. Using your pry bar, push each pot into the caliper carefully - you'll notice the alternate pot on the same side will likely start to push out as the fluid transfers in the caliper. If you alternate between them, and use your fingers to hold the other pot down, you can slowly work both back so they are flush with the inside of the caliper. Do the other side of the caliper after the first side pad is in for ease.

This is why we unscrewed the brake fluid reservoir earlier - the fluid from the brake calipers and lines needs to go somewhere - back into the reservoir.

...

Lastly, we may have excess fluid in the reservoir from where we pushed the pots back into the caliper.

Nice writeup, but I see one potential issue. Instead of pushing the fluid back into the reservoir, connect a catch bottle to the bleeder valve, crack the bleeder valve and push the fluid out the valve. The advantages to this method are:

• The most heated brake fluid (worst condition) is in the caliper. By pushing this out the bleeder, you're quickly disposing of it, instead of pushing it back where it will continue to be used.
• There is zero chance of having the reservoir overflow. We don't need to put paint-eating brake fluid all over the car, even where it's hidden (rust happens ).

Also, there are several inexpensive tools designed for the task of spreading the brake pads: https://www.amazon.com/s?k=Brake+pad...f=nb_sb_noss_2

I use one like the OTC 7034, but I've never tried it on calipers that don't get removed for a pad replacement. Perhaps something like the "Five Bananas" unit will work better for the Sport/Performance calipers.

[Onizukachan]

If you crack the valve you hav3 to bleed the brakes. This way you don’t. It is also less messy.
Note:
If you don’t top up between pad changes, and you Shouldn’t!, it can’t overflow. Period.


If you have a single piston caliper, like 330/312/300 rotors do, you can use a 8-9” c clamp (I think that’s what size mine is) To push the pads back before you even loosen one bolt. Put one side on the back of the caliper and the other on the front pad. Compress and it slides the caliper back over to start point compressing the piston for you. And giving lots of wiggle room to get it off easily.

[Daggers]

Also, those bleed nipples do love to sheer off. And then you're in a world of pain! Because I track my F80, and they get extremely hot, I actually have the main dealer do brake fluid changes so I don't have to touch the bleed nipple. If it shears off when they do it, that's their problem. If it shears off in my garage, I have to find a replacement caliper!

[SystemOfUrdaW]

awsome write up Daggers
anyone knows the part number for rotor screw on "m sport brake"
needs to fit on a F30 2016 340i Xdrive
thanks

[Daggers]

34211161806

[F30zoom]

Do you need to replace these if they haven’t been activated ?

Thanks

[Daggers]

Originally Posted by F30zoom

Do you need to replace these if they haven’t been activated ?

Thanks

If you mean the wear sensors, nope. Just be careful getting them out of the pads as they become brittle with the heat and damage easily.

[F30zoom]

Originally Posted by Daggers

If you mean the wear sensors, nope. Just be careful getting them out of the pads as they become brittle with the heat and damage easily.

Thank you

[Jvac]

Thanks so much for a great writeup. As someone who has been tackling more and more of my own maintenance jobs but has never done brakes, it's extremely helpful. To me this is the kind of task that isn't so complicated, but has a few important points that aren't really addressed in the maintenance manuals because they assume the reader is experienced. Threads like these hit all of those points and give folks like me the confidence we need to do it and the info we need to do it right. I'm betting I will need to do new pads and possibly rotors before long. Many thanks for the guide.

[F30zoom]

@Daggers

How do you find the yellow stuff pads over OEM? + what make of discs do you use ? Are they all from EBC ? I have the m sport blue brakes

Thanks again and it’s an excellent write up

[F30zoom]

Has anyone done this on the 4 pot Brembo's? If so is it difficult to do with the caliper on the car? The part is listed in realoem.


Thanks

[casualDIYer]

Thanks @Daggers for the tips. I referenced this DIY doing my first Brembo 4-piston brake job. In my case I ran into some challenges. The first one, how do I sneak a QuickJack into the garage so my wife won’t notice. This problem remains unsolved so I used jack stands.

Like always, not instructions here. Just a diary of how I managed to avoid serious injury while maintaining my own car. I am not a mechanic. Use at your own risk.

Given the jack stand part is the most dangerous, can there ever be enough info passed on about the importance of using them? As mentioned in the DIY, you want the entire front of the car up so you can use the opposite side wheel to turn the steering rack so that the caliper you are working on points out, away from the car. Attempting to turn the steering rack with one side leaning on the ground is going to make your life tough because 425kg of car is leaning on a nice wide grippy tire opposite to the side you’re working on. And let’s face it, you want to buy new jackstands so use this an excuse.

Finding the front jack point / jackstand placement
You need to research this carefully as it might be different for xDrive vs. normal (i.e. RWD) cars. I have an xDrive car and you can see in the photo where my jack point target it. Do not use the plate behind that point to jack up the car because that’s an extensive mistake if you’re wrong. Instead of paying off my mortgage I used a couple of home made plywood ramps to get the car into the air so I could clearly see where the jack needed to go. While on the wooden ramps, I crawl under the car (because one needs to do unsafe things to make a point about safety), positioning the jack right on target. Using another piece of wood (value in 2019: $0.90, value in 2021: $90.00) as a jack pad to prevent scratching the car, I jack the car up to roughly the height of the jack stand plus 1~3 clicks of the support. I then move the jack stand under the one of car's 4 jackpads then move the jack stand support into the pad. This makes it easier to get the car right on the support rather than play rocker panel destruction (plus optional door gouge) roulette.





Alt tools?
I found the perfect sized punch tool for the job on Amazon. The Mayhew tools 21510 (4mm). This tool is not called ‘punch tool’ but called ‘21510’. Maybe it’s a punch tool professional code or something but yeah, it’s called 21510 and that’s it. How the hell did I find it? A global pandemic makes for a lot/lot of wasted time. I also used the Lisle 29100 Quick Quad Pad Spreader, which actually works on single and dual piston calipers as well. It’s like getting 3 tools in one. Got 6 pistons? Probably need another tool. You will still need a pry bar/screw driver to move the brake pad off the rotor but once the old pads are out, spreading the pistons with this tool is very easy.




Brake pin alignment?
It seems getting the brake pins out was ‘easy-ish’ (breaking/disassembling stuff is always easier) but getting them in and matching up all holes was a bit challenging. I found using the punch tool and matching it with the pin made the job of alignment easier.

[CanadianHorseMan]

Hey all, I read the whole thread. Excellent post Daggers!

Anyway, I'm a torque guy. I want torque specs. lol. Thanks for the torque specs for the front. Do you have them for the rear brake job?

All my calipers are way past being shitty, haha. I bought a 2019 Gran Coupe with perf pkg used, must of been sitting in a lot for a while and all the rotors were completely trashed...I've lived with them for about a year, but they're soooo bad now I can't stand it. Anyway got myself a full set of Brembo discs and Hawk HPS 5.0 pads (hopefully the right choice, so many opinions out there).

Anyway, rambling done, torque for the rears would be awesome.


Rob

[Liv6992]

Thanks, best guide!

[Itogliano]

Originally Posted by Vinboyblue

Guys, what is the left and right markings on the pads for? does it matter which side the pads are on?

Ignoring the fact your question is three years old at this point, I just did my replacement brake job and saw the markings you mean. Those are for the manufacturer of the pad, to make sure the metal retainers aren't assembled backwards.

[CanadianHorseMan]

K, I feel like an amateur when asking this (I have replaced rotors and discs before)...but I just downloaded the service manual and it says to "Replace Screws!" ....referring to the caliper bracket bolts (the 110 Nm bolts).

Yes with an exclamation mark.

Do you guys actually do this? I've never done this on any of my cars.



R

[Onizukachan]

Negatory. Unless they are crusty I simply reuse. It’s never a bad idea to have a spare on hand in case one snaps or rounds out and you have to drill it out though.

[CanadianHorseMan]

Originally Posted by Onizukachan

Negatory. Unless they are crusty I simply reuse. It’s never a bad idea to have a spare on hand in case one snaps or rounds out and you have to drill it out though.

Yup my front ones looked like new. Just re-used them…makes no sense to me to replace.

Just did an entire brake job on a 2019 440i Gran Coupe xDrive, M-Sport Brembo brakes. Took me about 6 hours lol. The fronts were pretty easy peasy…literally two bolts. But Holy Moses, the back was a mess.

Getting those caliper mounting bolts out was a nightmare cause they were so gummed up with the factory “3M ThreadLocker”, the manual says to replace them cause they’re stretch bolts, but no thanks, I really don’t see a point replacing M12 bolts and the new ones will be just as f’d up getting them in and out the next time. I cleaned up real nice, sprayed some Loctite 6649 (Activator - Surface prep) and some Loctite Blue (242 — this is important, not 241 like Cantire sells, 242 is higher heat resistance, oil resistant, higher water resistance, and stronger, and especially stronger with the 6649, I believe the Loctite tech docs say 25% stronger, and it is as I’ve taken bolts out with and without the prep).

Anyway, torqued the rear M12 bolts to 110 Nm just like the front and called it a day.

Most messed up brake job I’ve ever done. On the back I literally had to stick a small pry bar in between the pad and old rotor to move the piston back so I could pull the pads out. On top of that I could only do this on the outside pad on each back caliper. Both inside pads had rusted so badly that they were fused to the caliper and the backing plate literally came off the pad when I tried to pry it out. I scrapped all the gunk off the caliper pad slide surfaces and brake cleaner like mad and scrubbed with a small stainless wire brush. They got nice and flat again and I lubed em up nice. New pads slid in perfectly.

Is this normal? Is that why Daggers recommends a small pry bar?

Anyway, great write up, used this with the service manual. Helped a lot.

Car handles soooo much better it’s not even funny. I’m still hesitant to touch my brake pedal cause I’m so use to the car shuttering and I hate the feeling lol. But stops so smooth and nice.

For reference I got

Brembo Rotors:

2X116-3698-8 @ $ 134.990 ea.
09.C401.13 BREM $ 269.98

2X113-7723-0 @ $ 142.490 ea.
09.C399.13 BREM $ 284.98

And Hawk Performance HPS 5.0 Pads:

Hawk Performance HB765B.664 - Disc Brake Pad - (HPS 5.0 w/0.664" Thickness)
CAD$204.95

Hawk Performance HB766B.624 - Disc Brake Pad - (HPS 5.0 w/0.624" Thickness)
CAD$189.67

This is for M-Sport (blue calipers) and is in Canadian dollars.


Rob

[Onizukachan]

Not at all. I had 0 issues removing my 312/300 when I upgraded to 340/330 last year at 60k+ miles.

[CanadianHorseMan]

Originally Posted by Onizukachan

Not at all. I had 0 issues removing my 312/300 when I upgraded to 340/330 last year at 60k+ miles.

Wow, so odd. I guess since I did it this time I’ll know if why/if it’s messed up the next time

[SD Convert]

Originally Posted by CanadianHorseMan

torqued the rear M12 bolts to 110 Nm just like the front and called it a day.

The correct torque for the rear bolts with 2-piston calipers is 50 Nm +60˚. This is referred to as "Torque to Yield". It is intended to permanently stretch the bolt, which weakens it. This is why you should replace the rear bolts. At under $4 per bolt (https://www.getbmwparts.com/oem-part...lt-34206850536), it doesn't make sense to use a stretched/weakened bolt.

[CanadianHorseMan]

Originally Posted by SD Convert

The correct torque for the rear bolts with 2-piston calipers is 50 Nm +60˚. This is referred to as "Torque to Yield". It is intended to permanently stretch the bolt, which weakens it. This is why you should replace the rear bolts. At under $4 per bolt (https://www.getbmwparts.com/oem-part...lt-34206850536), it doesn't make sense to use a stretched/weakened bolt.

I am aware what they are and what the manual says. If I could replace them the next time with a non-stretch bolt I will. I'm not dealing with that factory ThreadLocker again. I would replace them with the same bolts that are in the front but they are different lengths so that's probably not an option. I find it highly unlikely that a bolt of this caliber is just going to break apart after re-using it once, but I'm not debating it, just stating what I decided to do with them. Some replace them, some don't, do what you feel comfortable with.

R