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DIY brake maintenance, anyone has caliper torque specs? Rusty brake rotors

DIY brake maintenance, anyone has caliper torque specs? Rusty brake rotors

My rear rotors are very rusty, even a bit on the driver's side front. I stood on the brakes couple of times at high speed in an attempt to get rid of the surface rust, but it only took off a bit. There are still rings of rust around the rear rotors. I think my rear brake calipers are a bit seized up, think it's been an issue for a while now, as even back in the summer it takes a long time to rid the surface rust from after a car wash. Not surprising since the car barely ever uses the brakes, and on top of that salty winter roads here. I've seen this issue on hybrid cars in which the rear calipers are completely seized up, it was so bad that I needed to use an impact wrench to remove one of the sliding pins from the caliper, with the inner brake pad looking like a wedge. From then on I thought to myself I should lube them up once a year.

Time to get dirty on the Tesla. Does anyone know the torque specs for the rear caliper bracket and sliding pins? I could not find it after much search. I have a dual motor non-P with the regular brakes, so the front calipers are fixed and I just tap out the pins to remove the pads vs the rear which is a floating caliper. On another car I worked on, I broke the head off the sliding pin from over torquing lol, from not having the proper torque spec. Took me a long time to drill the rest of that pin out of there. I don't want to do this without knowing the proper torque specs now.

jordanrichard | 14 février 2020

I have a 2014 MS and noticed just yesterday that the front right caliper was coated in rust, while the others were clean. My initial thought was that the pads are stuck in place, preventing the pistons from moving the pads inward, to brake the car. In net affect, a seized brake. However, if that were the case, when applying the brakes, the car would have pulled to the left. I have had seized brakes before and know what happens when calipers seize up. I reduce my re-gen to "Low", purposely applied firm pressure on brakes, starting at 50 mph and that cleaned up the rotor.

gmr6415 | 14 février 2020

If you can drive it without them dragging and park is working then they aren't seized.

EPwolf | 14 février 2020

@h2ev: What part of the country are you in? I'm in the Philadelphia area. We haven't had much snow this winter, but they've brined/salted the roads here a few times for various storms. I haven't had rusty rotors at all. It's been cold enough that the regen has been disabled enough times to have me pressing the brake pedal from time to time. Also, I've read suggestions from Tesla folks (can't remember where) that regen should be disabled once in a while to keep the brakes working properly mechanically. That is a very good idea throughout the year, but I admit I haven't done it even in warm weather, and I haven't bothered with it in the winter because of the cold weather. I chuckled a little about you braking a bolt from over-torquing. I have changed countless brake pads, on countless cars (both domestic and foreign). Never broke a bolt and never had torque specs. I must be a wimp!

RayNLA | 15 février 2020

Rich Rebuilds did a video about this.
Also turn regen to standard to use the brakes more every so often.
https://youtu.be/9h3W-0iWYvc

h2ev | 16 février 2020

They're not completely seized, but certainly not sliding as freely as they should be, with all the rust that remain on the rotors even after slamming on the brakes at high speed.

I'm in north NJ. It's been a very mild winter, with the biggest snow fall being 4" just once, and just a coating to an inch maybe 3-4 times. Figures that would be the case after I buy snow tires for the car lol. I will definitely make it a routine to drive the car with regen on low.

Slight correction on breaking the bolt head. It was the caliper bracket bolt, not the sliding pin bolt, as that bolt will be spinning before it breaks.

I saw that video a little while back, which is how I found out that the front calipers are fixed vs floating on the rear, but he didn't talk about torque specs. I know experienced can techs do it just by feel.

I will go ahead and do this when spring comes. Will post some before and after pics.

jacapuano | 16 février 2020

I believe Tesla recommends lubricating the calipers every 12,000 miles . Pretty sure I saw it on the website.

h2ev | 16 février 2020

Yes, I think those of us that live in snowy regions should heed that advice, and probably should turn regen on low once in a while.

h2ev | 16 février 2020

Pics. It's already a lot cleaner after I slammed on the brakes going 80 (late at night, no cars around) with regen on low, even felt the ABS kick in.

Front:
https://imgur.com/SIYnR0i

Rear:
https://imgur.com/XNneeDv

Twochewy | 16 février 2020

Your front rotor is scored and the rear lacks full pad engagement. If you don't have the skill to DIY you should take your M3 to a mechanic to have the brake work done. Regen won't help you in an emergency stop.

ElectricAlex | 16 février 2020

Turn regen off for a couple days, they will be clean

gballant4570 | 16 février 2020

No need to fool with your regen settings - just make sure you put your foot on the brake pedal and use it at least once or twice every time you drive it to exercise the equipment. Its really easy to not use them, especially if your routine driving doesn't involve many traffic lights to surprise you with sudden stops.

Twochewy | 16 février 2020

OP probably lives in the Northeast where road salt is the norm in winter. Need regular brake maintenance there. Otherwise, be prepared for unsafe stopping power.

jordanrichard | 16 février 2020

I am in CT and in 6 years (winters) I have never had the brakes serviced. Still on original pads and rotors. Being in the Northeast, during the winter months we do use our brakes more often due to the frequent periods of re-gen limitation.

If one wants to do check their brakes for rust on the contact points, it’s not that hard to do. Pop the pads out, wire brush any rust off, apply some brake grease/high friction grease to the the edges of the brake pad’s backing plate, reinsert into caliper.

As for the torque spec, I am sure there is one, but just wrench it down really hard and call it a day.