[scotes]

I've got a 2020 M340i with about 33k miles on it. The warranty just came up so I took it in to the dealer for their free inspection to see if there was anything outstanding that needs doing and they brought up the brakes - I have the M-Sport brakes.

Front pads are at 4mm; front rotors at 34.4mm; min spec for front rotors is 34.4mm
Rear pads are at 3mm; rear rotors at 22.5mm; min spec for rear rotors is - I think - 22.4

Seems convenient the rotors are right at minimum spec...

Can I get away with just doing pads on this go around or do I really need to do the rotors as well? Also, there are plenty of how-tos on doing the pads but does anyone have a link to a how-to on doing the rotors as well? Mainly for how to remove the calipers and put them back on. Thanks!

[jb606]

Do yourself a favor and get both pads and rotors. It doesn't add that much to the total cost, unless you have a buddy that can turn them for some adult beverages. The calipers should just unbolt from the back of the upright, but you'll need to check to see if the bolts are one time use. In the VW/Audi world they are...

[reala]

I normally replace rotors after 2 pad replacements.

[scotes]

Originally Posted by jb606

Do yourself a favor and get both pads and rotors. It doesn't add that much to the total cost, unless you have a buddy that can turn them for some adult beverages. The calipers should just unbolt from the back of the upright, but you'll need to check to see if the bolts are one time use. In the VW/Audi world they are...

Buying new rotors easily adds about another $1000+ to the cost of the job parts wise so unfortunately it does add quite a bit to the total cost.

[a.summers86]

Shouldn't need new disks after 33k miles.

[k4sh_90]

In the same boat with my warranty and dealership told me the same thing regarding the brakes. I spent a weekend and replaced the rotors, pads, bolts, both sensors, retaining springs, and caliper pins. They’re not a terrible DIY project, if you’re into the sort of thing

[rsn_2296]

Just adding my experience, I have a 330i but with the same brakes as the 340i (blue M brakes) I’m at 23k and had to replace the rear pads and rotors. I’ve still got meat on the fronts but that will come up relatively soon.

Went to the dealer and 2 shops and they all confirmed this but the dealer was more than ready to do all 4 at once. Both the Indy shops were honest and told me I didn’t need to get all of them replaced at once.

I replaced pads and rotors for the rear at $850 including labor. I think the fronts will cost about $900.

[jb606]

Originally Posted by scotes

Buying new rotors easily adds about another $1000+ to the cost of the job parts wise so unfortunately it does add quite a bit to the total cost.

Very true OE rotors are pricey (just looked ~400 for the fronts!). If you don't have to have OE, check out fcp euro. Or keep up the every other pad change. As long as the rotors are above thick enough and don't warp you save more than a few $$$

[tturedraider]

Originally Posted by reala

I normally replace rotors after 2 pad replacements.

Originally Posted by a.summers86

Shouldn't need new disks after 33k miles.

I’m old school and I believe in machining the rotors once before replacing them. Especially when the replacement is on my dime.

[scotes]

Thanks for the responses. I took a look at the rotors and all four have a bit of a lip at the edge. From what I've looked into if there's a lip they should be replaced. I'll end up going with the Zimmerman aftermarket rotors as they are quite a bit cheaper than OEM and seem to be as good if not better.

Now to only find a diy on pulling the calipers off so I can replace the rotors...

[Bc2005]

Pulling off the caliper bracket was simple on the F30, and I assume it’s similar on the G20. You remove the caliper (piston and pads) like you would for a brake job, and then the caliper bracket is held on with two more bolts. Once that’s out of the way you can remove the rotor. I’m not sure if the rotor has a set screw to retain it.

[k4sh_90]

Originally Posted by Bc2005

Pulling off the caliper bracket was simple on the F30, and I assume it’s similar on the G20. You remove the caliper (piston and pads) like you would for a brake job, and then the caliper bracket is held on with two more bolts. Once that’s out of the way you can remove the rotor. I’m not sure if the rotor has a set screw to retain it.

Pretty much the flow to get the caliper off on the G20. Two E-Torx bolts are in the back that secure the caliper. Same process on both axles. The rotor has a 6mm hex screw to hold it to the hub.

[scotes]

Thanks on the caliper assembly. Yeah, looked like just a couple of bolts and then just make sure I've got a hanger for it so it doesn't stress the brake line.

Any idea on the torque specs for those bolts when they go back in?