Shimano Deore M615 brake issue

clydefrog

Hi, I've got a question for anybody who has these brakes or similar Shimano brakes. I just bought one and the pads don't sit right back against the caliper as the pistons stick out a tiny bit and can't be pushed back to be flush with the caliper body. Is this quite normal or does it mean something is wrong with it? I've been told it can take time for them to bed in but I'd just like to see what other owners have found with theirs.

Chunkers1980

Why are you asking again?

clydefrog

Chunkers1980 wrote:

Why are you asking again?

Because I thought in this forum I might find somebody who's bought the same brake who can comment on it. Sorry I'm not trying to make multiple posts or anything but this one is only related to the piston thing, not the other things that the other thread is about. As you said in the other thread I probably am over-thinking it but I'd just like to know for sure I've not got a problematic component.

cooldad

Send them back - you are obviously not happy - CRC are excellent with returns - it's all free and you just pack them up and take them to the nearest depot - ask for replacements as yours are scratched - as SS said in a post on the other thread (not confusing at all, is it?), they might have been on another bike - might even have been returns. Get them to send you another set.

clydefrog

If I return it I am thinking of getting the front + rear + rotors set for just under £100 from Merlin instead and replacing the rear Avid Exlir 1 and avid rotors currently on the bike. In fact the same stuff would come to the same price from CRC but I'll see if Merlins are also OEM and I also don't want to get some other possibly used item from CRC.

clydefrog

Well from seeing this image on epicbleedsolutions showing the previous deore model (but the inside looks the same) showing the caliper with the pistons "pushed as far back as they will go", going off that it appears that mine is normal and the edges of the pistons are supposed to stick up just above the inside surface of the caliper:

cooldad

From other thread

cooldad wrote:

Hallelujah

YateleyChap

clydefrog wrote:

Hi, I've got a question for anybody who has these brakes or similar Shimano brakes. I just bought one and the pads don't sit right back against the caliper as the pistons stick out a tiny bit and can't be pushed back to be flush with the caliper body. Is this quite normal or does it mean something is wrong with it? I've been told it can take time for them to bed in but I'd just like to see what other owners have found with theirs.

Didn't see the other thread but to me this is normal. I have the previous Deore version and have bled them myself several times (using the epic bleed kit) as did my LBS before I learnt how to, and every time the pistons are never perfectly flush. If the levers feel firm and the bike stops when you pull them then I really wouldn't worry about it.

clydefrog

YateleyChap wrote:

clydefrog wrote:

Hi, I've got a question for anybody who has these brakes or similar Shimano brakes. I just bought one and the pads don't sit right back against the caliper as the pistons stick out a tiny bit and can't be pushed back to be flush with the caliper body. Is this quite normal or does it mean something is wrong with it? I've been told it can take time for them to bed in but I'd just like to see what other owners have found with theirs.

Didn't see the other thread but to me this is normal. I have the previous Deore version and have bled them myself several times (using the epic bleed kit) as did my LBS before I learnt how to, and every time the pistons are never perfectly flush. If the levers feel firm and the bike stops when you pull them then I really wouldn't worry about it.

Thanks for the reply, and yeah I think I was just worrying about nothing, it is probably fine. Does that bleed kit work well by the way? One other thing, the movement of the 2 pistons isn't completely even but there's no sticking or anything, one just moves slightly further out than the other, I take it this is also normal and nothing to worry about?

YateleyChap

No probs. The epic kit is great in my view, not very expensive and gives a really good bleed every time. The instructions that come with it are very clear as well.

If you haven't done so already you can advance the pistons a bit (with the pads removed), clean any gunk off with a q-tip and then dab some of the shimano mineral oil round them, push back in gently and advance a little again just to make sure they're lubed ok and are moving free of any grime. Reset them back into the calipers and spray some IPA or brake cleaner to remove any excess oil before reinstalling the pads. The pistons are quite delicate so just take it easy whenever resetting them back into the calipers. I seem to recall thinking that my pistons were a bit uneven, but once setup properly the gap either side between pads and rotor is very small so they engage evenly and don't move the rotor to the side when pulling the lever.

clydefrog

The brake is brand new and hasn't been used yet (I hope - because as mentioned in the other thread some kind of dirt or dust came off the resin pads onto a piece of paper I put between them and there's also a chipped bit of paint and a small scratch on the calipers edge where the rotor goes in) so I shouldn't need to clean it, it should be perfect as far as being properly lubricated and no dirt in the pistons goes.

The Rookie

To state the bleedin' obvious, as long as you could get the disc between the pads the pistons were as far back as they would ever need to be.