07 S550: Needs rear brakes?

It's pronounced "chassy." Brakes, suspension...things that make the car fun or a death trap
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kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

07 S550: Needs rear brakes?

Post by kevm14 »

According to the dealer it does. They did a courtesy inspection when they mounted my tires. Everything checked out except rear brakes which they said were down to 2mm on the rear. Well....glad they saw that I guess. And it's good the rest of it checked out.
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And to be nice I said yes, you can provide me a quote. It's unreasonably high as expected.
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$731.96. Well let me hilariously beat that with Rockauto prices.

I did check the rotors through the wheels. Quite an outer ridge and a wavy surface. So it's due for rotors as well. That's fine.

I think I have the 320mm rear rotors. Sports package or AWD cars I guess?

I could get this done via Rockauto for as cheap as $84 (before tax/shipping). But I don't like bottom of the barrel brakes. So what I ended up with was FCP Euro Zimmerman rotors, Akebono pads (they don't dust apparently) and a wear sensor for $234.93 shipped. Rockauto has the same pads but different rotors (and sensor) which would have been $192.43 shipped. Considering FCP Euro is lifetime warranty, I guess the extra cost is worth it.
kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: 07 S550: Needs rear brakes?

Post by kevm14 »

Wow. The free 4 day shipping is faster than expected (given their CT warehouse, I guess it makes sense). Says arriving tomorrow.
kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: 07 S550: Needs rear brakes?

Post by kevm14 »

Did this yesterday. Totally routine and easy job with a few highlights.

Side note: it was pretty comfortable doing this work having the car so high. Much less leaning over or crawling on the ground to try to work a bolt or something (this is the front of the car obviously but you get the idea).
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- Remove wheels
- Remove T30 rotor bolt.
- Use C-clamp to retract caliper piston. Just go from the outer pad to the outside of the caliper piston near the brake line. These are simple 1 piston sliding calipers.
- Pop protective covers off of the caliper pin slides
- Loosen caliper pins. They were....6mm allen? Something like that
- Remove spring clip from outer caliper to caliper bracket
- Pull caliper off bracket. Outer pad will stay in the bracket and inner pad will stay with caliper piston.
- Remove caliper bracket bolts. They are 18mm and quite tight. Set bracket aside.
- Heat and beat rotor until it comes off the hub. I probably heated for 30 seconds and did some whacks. Took a few tries on the driver's side and I think the first try on the passenger side. Not much of a fight. Evidence below.
- Wire wheel hub and apply anti-seize
- Clean new rotor back side and install.
- Install T30 bolt
- Clean outer rotor surface
- Clean and grease caliper bracket. Reinstall. The bolts had blue Loctite but I didn't use any nor did I torque the bolts. I made them tight.
- Install new outer pad into bracket
- Remove old inner pad, grease caliper piston and install new inner pad into caliper
- Set caliper on bracket/pads
- Remove, clean and grease slide pins
- Install and tighten slide pins
- Install protective covers (had to use old ones)
- Install outer spring clip. My expensive-ass Akebono pads didn't come with this, either, which did piss me off. Next time I guess I'll have to get those separately. I could also just order a pair, pull the wheels sometime and put new ones on. I may do that.

A pad slap would have been hilariously easy on this but depending on the pads chosen, it may need rotors every time. Just depends. I bought these expensive Akebonos that aren't supposed to dust but still stop well. Not sure how they treat rotors. Doing rotors each time is not the end of the world either way.

So that's it. The only real interesting thing that happened is on the passenger side, the lower caliper bracket bolt came out really hard. I think it took some threads with it, or it was damaged on reinstallation on the previous brake job. Hard to say for sure. The caliper bracket bolts are M12x1.5. I chased the threads of the bolt with a die which cleaned up easy, which means what was on the threads was from the knuckle threads. Ugh.

Was able to just have enough room to thread my tap into the caliper bracket and carefully clean out the hole. I got it so the bolt threaded in by hand so that worked out thankfully. I think if I just tried to jam the bolt back in that would have been a bad day. It worked out fine.

You can see the driver's side pads below. They are definitely worn and not much left, but not dangerously low, either. "Due for a brake job" was a fair assessment overall and DEFINITELY due considering the long drive I have planned in Feb, although that is mostly highway.
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kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: 07 S550: Needs rear brakes?

Post by kevm14 »

Bad news: the rear brakes drag. Man. More of this BS. Had this on the STS and SRX and now the S550. I guess it is a thing.

However I am going to live dangerously and try new caliper pistons and seals. Never done that before and honestly it looks rather easy. And I won't even have to unhook the brake line from the caliper to do it. I bought special Red Rubber grease to lubricate the piston and seal for reassembly. Honestly I think this is going to work out really well. I am also going to replace all the hardware for best results. Still cheaper than reman calipers.
kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: 07 S550: Needs rear brakes?

Post by kevm14 »

Brake bleed order and torques. Good news: this car has a normal braking system from a bleeding perspective and I may be able to use my Motive power bleeder, too. Looks like all bleeders are 14 Nm which is about 10 lb-ft. I could be ridiculous and torque them.
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W221 bleed brake fluid.pdf
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kevm14
Posts: 15241
Joined: Wed Oct 23, 2013 10:28 pm

Re: 07 S550: Needs rear brakes?

Post by kevm14 »

The new pistons and seals fixed it up. Long-ass video here: https://youtu.be/JYB_OBI5HC0

Also flushed/bled with the Motive power bleeder and enhanced the flow with my trusty Mityvac. Did like 20 psi at the reservoir and pulled a vacuum at the caliper bleeder.

There were some tricky moments but once I learned the other side went way faster. This was enjoyable and satisfying and IMO a solution that I should have considered when I first ran into caliper sticking issues on the SRX and STS. If it happens on the SRX I will try this for sure. We've been trained never to press the brake pedal when the caliper is off the car because the "piston could fly out." Well, it doesn't fly out, that's for sure.
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