Big brake kit upgrade issue [SOLVED: purchased the wrong rear rotors]

[renaldo0613]

Hello all. I’ve done my research on our forum and google of course before pulling the trigger to upgrade my M37X to BBK. I was able to get the upgrade done, however we ran into an unforeseen issue that I didn’t see coming. I did the rears first, haven’t gotten time to do the fronts. I knew from doing research that the rear dust shields would need to be removed or trimmed.

I opted to trim them, as removing involved removing the rear axle Anyways the rear rotors would not clear the parking break pads for s**t. If I’m correct (please correct me if I’m wrong) the rear rotors for bbk measure in at 350mm and the fronts measure in at 355mm. I will post some photos up later on when I get to my laptop to show exactly what I’m taking about.

[EdBwoy]

Are the BBK rotors new and correct part # for the M37S? I don't have the dimensions with me, but from what I'm getting, the brake shoes were a little too wide for the rotor hat to slide on, right?

Did you try turning the adjuster screw to bring them back in? I mean, you said you got it done, so I'd lIke to see the pictures.

[Malbec 56 Beast]

Yes the rotors are 355 and 350 respectively.

You need to make sure that the clippers are the correct ones for the M. I willing to bet that there are slight differences between models so that is the next verification are the calipers being correct.

Good luck

Andy

[renaldo0613]

Are the BBK rotors new and correct part # for the M37S? I don't have the dimensions with me, but from what I'm getting, the brake shoes were a little too wide for the rotor hat to slide on, right?

Did you try turning the adjuster screw to bring them back in? I mean, you said you got it done, so I'd lIke to see the pictures.

yes the brake shoes were to wide for the new rotors to clear and sit flush.

[renaldo0613]

Yes the rotors are 355 and 350 respectively.

You need to make sure that the clippers are the correct ones for the M. I willing to bet that there are slight differences between models so that is the next verification are the calipers being correct.

Good luck

Andy

Calipers botled right on with no issue what so ever. This was happening when test fitting the new rotors.

[renaldo0613]

Here are some pics that could help:

Notice how the rotor will not sit flush due to the parking brake shoes. I turned the adjuster nut and got the parking break as tight as possible. Ultimateley the only way I could get them on was to remove the parking brake temporarily as I was in a crunch, my car was sitting for 10 days due to the OEM caliper seized up on me and began to drag on the driver side rear rotor. So bad that it was creating sparks while driving smh.

[renaldo0613]

Below you will find a link to the pads and rotors set up that I had decided to go with. The calipers were ordered from RockAuto part number: S6182

https://maxbrakes.com/i-22804789-slotte ... e-kit.html

[EdBwoy]

I tried to check on the part numbers on the website comparing a g37, 370z, m37/m56/q70 and I found a different part number than what you posted. Honestly though, trying to navigate that website was giving me a headache, so I'll try when I get home.

Also, I'll try to take measurements of my rear rotors. Your rear one might have the correct diameter on the large disc, but the hat seems a little small to me. Idk how valid my assumption is, but it seems like there is quite a large taper to yours... which would mean the inner diameter would be smaller than the diameter of the brake shoes.

Sometimes when the rotor will slide over only one end of the brake shoes, it's just a matter of wiggling the shoes in/out/clockwise/CCW until the shoes are happy. Mostly on heavily used rotors that have the lip left left behind as the shoes groove the rotor.
It seems you guys were dealing with something else here.

So, I'll take my measurements later, even if it doesn't help you at this very moment it will satisfy my curiosity.
Might you have compared your mounting dimensions on the new and old rotors?

[EdBwoy]

To add
It's a silly question but I have to ask, the parking brake wasn't engaged as you were doing the job, right?
The adjuster is definitely turned down, but the actuator side of the shoes isn't pictured.

[renaldo0613]

I tried to check on the part numbers on the website comparing a g37, 370z, m37/m56/q70 and I found a different part number than what you posted. Honestly though, trying to navigate that website was giving me a headache, so I'll try when I get home.

Also, I'll try to take measurements of my rear rotors. Your rear one might have the correct diameter on the large disc, but the hat seems a little small to me. Idk how valid my assumption is, but it seems like there is quite a large taper to yours... which would mean the inner diameter would be smaller than the diameter of the brake shoes.

Sometimes when the rotor will slide over only one end of the brake shoes, it's just a matter of wiggling the shoes in/out/clockwise/CCW until the shoes are happy. Mostly on heavily used rotors that have the lip left left behind as the shoes groove the rotor.
It seems you guys were dealing with something else here.

So, I'll take my measurements later, even if it doesn't help you at this very moment it will satisfy my curiosity.
Might you have compared your mounting dimensions on the new and old rotors?

LOL yes that website is a bit of pain to navigate thru via mobile device. Your measurements would greatly be appreciated to kill the curious cat in the room. The hat was definitely smaller...I would say in comparison to the Non sport OEM rotors, difference was between a 1\2"- 1' I believe I have a photo showing the difference that I can post up.

Yes, the parking brake was disengaged while trying to install the new rotors as well. We (my brother, and I were) were totally confused about the fitment issue.

[renaldo0613]

Here we go. Use my brothers thumb as a guide to get a rough idea on the size difference.





I would say about an inch difference.

[Malbec 56 Beast]

That's what I said earlier, it's the wrong rotor.

Good luck

[wideopn11]

^^^What he said^^^
I know there are some other options for BBK but most of us go with the sport Akebono and stoptech rotors. I had zero issues installing mine except for of course trimming the dust shield.

[EdBwoy]

I snapped some quick ones to show some measurements.
You know, I have the same breaker bar, and I wish I had thought to use it, but I hope the tape measure will work just as well. Haha

13.75" overall diameter.
349.25mm

7.25" outer surface of hat
184.15mm

6.75" inner surface of hat (brake shoe clearance)
171.45mm

[k67p67]

I think all of the front rotors for Nissan/Infiniti Akebono setups are the same dimensions. The rears are not. My Q70 and 370Z use the same fronts but different rears.

[Malbec 56 Beast]

The 2013 M56xS is 355/350 fr/rr.

Is a pain but it'll be nice when done.

Good luck

[renaldo0613]

I snapped some quick ones to show some measurements.
You know, I have the same breaker bar, and I wish I had thought to use it, but I hope the tape measure will work just as well. Haha

Thanks for the measurements! That works out perfectly with the tape measure. So apparently even tho I ordered the "correct size" rotor it was wrong. The company that I ordered them from even confirmed with me that they would fit. Smh.

[renaldo0613]

The 2013 M56xS is 355/350 fr/rr.

Is a pain but it'll be nice when done.

Good luck

I guess they sent me the wrong rotor I suppose. Here is a screenshot of an email sent from the company before shipping out the rotors. Or perhaps I made a mistake.

[EdBwoy]

I noticed in the picture you attached that the M was conspicuously absent from the list, so I was curious again. As k67p67 mentioned before me, the rears are different. This is what I found for the sport models:

2012 M sport
Rear

• OEM. 43206 1CA0A
• Stoptech centric blanks. 120.42105CRY

Front

• OEM. 40206 JL00A
• Stoptech centric blanks. 125.42100CRY or 120.42100CRY

Parking brake shoe kit

• OEM. D4060 CA01A
• Autozone/ Duralast part # 869

2012 G37 coupe 6MT
Rear

• OEM. 43206 JL00A
• Stoptech centric blanks. 120.42101CRY

Front

• OEM. 40206 JL00A
• Stoptech centric blanks. 125.42100CRY or 120.42100CRY

Parking brake shoe kit

• OEM. D4060 JN00A
• Autozone/ Duralast part # 793

Watch out for the G37. According to stoptech, they had 3 brake configurations:

1. 355mm front, 350 rear. Akebono 4-pot front
2. 330mm front, 330 rear. Single-piston front
3. 320mm front, 307 rear. 2-piston front

2012 370z sport
Rear

• OEM. 43206 JL00A
• Stoptech centric blanks. 120.42101CRY

Front

• OEM. 40206 JL00A
• Stoptech centric blanks. 125.42100CRY or 120.42100CRY

Parking brake shoe kit

• OEM. D4060 JN00A
• Autozone/ Duralast part # 793

You'll notice that along with the rear rotor, the M's brake shoes are different too. For each model, the sport and base models use the same brake shoes, which means that a sport rotor should slide right onto a base.
My verdict? They might have sent you the right stuff but you might have put in the wrong order.

Btw, those pictures I posted above are G37 rotors I believe. I don't know yet whether the difference in rear part #s translates to any dimensional difference in the hat.