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Discussion Starter · #1 ·
As the title says, my rear Shimano M615 caliper failed this past Saturday. I was having to pump my brakes a lot before rides to get it firm - then I realized one of the pistons was stuck. I dislodged it, but then it started leaking. I had to use some regular mineral oil to get back but now I�m afraid I may have voided the warranty.

Since my bike is a 2017 and I believe the warranty is close to done anyway, I�m just going to replace the caliper. Thing is, not sure if I want to replace with the same one or upgrade to a SLX caliper or M6000 caliper. The performance was fine when they worked, I just don�t want to replace it with the same caliper and have more issues if they�re problematic. Should I just -
  1. Replace with same/similar M6000 caliper?
  2. Replace bad caliper with one new SLX caliper?
  3. Replace both calipers and levers with an upgraded SLX set f/r

I�d like to same some cash and keep what I got working, but I don�t want to have nagging issues in the future. Also, not sure about compatibility since SLX/XT use banjo bolts and mine does not.
 

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Replace with same. Save a buck. I don't think you'll see issues in the future. If the piston was stuck, and leaked after you dislodged it, you likely damaged the seal. The M615 is a rather reliable brake in my opinion.
 

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Discussion Starter · #3 ·
Replace with same. Save a buck. I don't think you'll see issues in the future. If the piston was stuck, and leaked after you dislodged it, you likely damaged the seal. The M615 is a rather reliable brake in my opinion.
Thanx for your input. The other question is, are the M615s and the M6000s the same? The M615 caliper is kinda hard to find.
 

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Make sure to get the correct ispec mount.

My M615 still works fine, 2016 stumpy. Not sure it is a common occurence.

If you upgrade the brakes I'd suggest doing front and rear. Seems sort of useless to upgrade the rear (especially to a 4 piston Shimano) and leave the same weak M615 up front. My two cents....
 

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Make sure to get the correct ispec mount.

My M615 still works fine, 2016 stumpy. Not sure it is a common occurence.

If you upgrade the brakes I'd suggest doing front and rear. Seems sort of useless to upgrade the rear (especially to a 4 piston Shimano) and leave the same weak M615 up front. My two cents....
If he is replacing caliper only he doesn't need to worry about I-spec, that would only be a concern if he were changing levers and had integrated shifters. But yes I would put the two piston caliper on the rear and the four piston caliper on the front even if it meant that I would have to swap both calipers.
The 520 caliper has the same hose interface as the 615's do so you don't have to worry about the banjo coupling.
https://365cycles.com/products/shim...c-brake-caliper-with-metal-pads-front-or-rear
 

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Discussion Starter · #7 ·
I don’t know if I’m going to have problems, but I just ordered the M6000 brake caliper to replace my damaged caliper. I could not find a single M615 caliper anywhere near me and I can get this M6000 caliper by Friday to ride this weekend. It seems to be the replacement for the M615 anyway. I would love to upgrade the whole brake system to SLX but I have other maintenance items to care for. I’ve not replaced a caliper before and I hope I don’t have issues with needing a new olive or insert.
 

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You should be fine unbolting the old one and putting the new one on, they are very similar. If the hose was not severely over tightened you may be able to use the same olive and pin insert, I’ve done it many times. When I upgraded my calipers I filled them first with Shimano oil by a syringe to the bleed port until old came out of the hose mount then connected them up; bleeding was real simple from that point.
 

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If he is replacing caliper only he doesn't need to worry about I-spec, that would only be a concern if he were changing levers and had integrated shifters. But yes I would put the two piston caliper on the rear and the four piston caliper on the front even if it meant that I would have to swap both calipers.
The 520 caliper has the same hose interface as the 615's do so you don't have to worry about the banjo coupling.
https://365cycles.com/products/shim...c-brake-caliper-with-metal-pads-front-or-rear
Crap, thanks for the correction. I misread 'caliper' as master cylinder, thinking OP was changing up at the bars. And I keep forgetting that bike manufacturers call that a 'lever'.
 

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Discussion Starter · #10 · (Edited)
So I ordered the replacement M6000 caliper and bleed kit on Tuesday and got it all on Thursday. Ordered from 365Cycles and they were very good with ship time and communication with what I actually needed. Very happy with them.

The M6000 series caliper was a little different from previous generations. The bleed screw is different - its made into the caliper and covered by a flush, round rubber grommet. I thought the bleed screw was missing until I found that. You no longer need a 7mm wrench, you can use a 3mm Allen key to loosen the bleed screw and put a hose on the nipple on the lower part of the caliper. It's much easier to bleed/fill with fluid compared to the combination bleed screw with nipple a part of the screw. Bleeding was painless with this setup and I did not have to use a new olive and insert either. Back in business before the weekend but it's thunder storming so, no riding today :(
See pics below:

Motorcycle accessories Black Grey Carbon Bicycle part
Product Technology Line Laptop accessory Computer accessory
 
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