My rear brake is basically non-existent right now. No stopping power and it just screams/howls under pressure. I'm going to clean the rotor and change the pads. Any recommendations for Shimano m395 pads? Or is a pad, a pad ? Cheers

We use uberbikes pads.

I had a good experience recently swapping metal pads for organic in a similar situation to you describe. I had been using Avid meat all pads and switched to Swiss Stop organic and got better, silent braking. I don't use your brakes but the Swiss Stops are available for loads of brakes. They are hellishly spendy though but are lasting well.
I wonder if cheaper organic pads would be as good

Clean the rotor then bake your pads in the oven at the highest setting for a while. That's recovered a few for me.

I stickwith OEM pads - Shimano for Shimano and Avid for Avid

I'm back to Shimano resin pads in my XTs and TRP Spyres, they run smoother than the recent lot of AM pads I've tried. A bit of noise in the wet but nothing major.

I have been using Uberbike sintered pads in Shimano XT brakes for five years, they are reasonably priced and last well.

You have probably checked this, but just in case...
If the caliper has been installed incorrectly (wrong adapter or spherical washers if fitted) you can get a situation where ultimately the unworn portion at the top of the pads touch, and the disc happily spins in the worn gap below.
Just saying in case it helps. Had this on a second hand bike I saw recently.

I think you're wasting your money changing pads. On lower end Shimano, I've always found the problem you describe to be a micro-leak at the piston. Cleaning / changing pads will 'cure' it in the very short term but the problem will return. Spend the money on a new caliper ... cheap enough if you shop about.

Bearbonesnorm wrote:I think you're wasting your money changing pads. On lower end Shimano, I've always found the problem you describe to be a micro-leak at the piston. Cleaning / changing pads will 'cure' it in the very short term but the problem will return. Spend the money on a new caliper ... cheap enough if you shop about.

I've come to the same conclusion with the basic Shimano brakes that came on my Longitude, belatedly, after much changing of pads, cleaning of rotors, cleaning of calipers, changing of rotors. Just going to spend some money on decent brakes soon... but not that soon because I accidentally bought 4 pairs of pads, when I mean to buy 4 pairs for my BB7s, and already have two pairs in stock

Uberbike RaceMatrix pads are by far the best I have tried....and I have tried a lot. Nothing will give a long term fix if you are leaking fluid but these give a great bite and no squeal if kept clean

I had this problem and ended up, after much cleaning and replacing of disks and pads, deciding it must be a small leak. No visible trace of any fluid. The problem would go away temporarily with heavy use (front brake) and getting nice and hot. Managed to solve it in the end by picking up a set of Magura MT5s.

Bearbonesnorm wrote:, I've always found the problem you describe to be a micro-leak at the piston. Cleaning / changing pads will 'cure' it in the very short term but the problem will return. Spend the money on a new caliper ... cheap enough if you shop about.

My experience matches this prognosis. My 5 year old shimano SLX's on the commuter bike (circa 35k miles I reckon they've covered minimum), that sound you're describing is consistent of a small leak. In the short term I found isopropyl cleaning the disc, and using a blowtorch on the pads as the best way to get rid of the contamination.
I'm halfway through replacing the calipers (i.e. have done so on the front, the rear isn't as bad and will do when I can be bothered!).

As for pads, my most recent experimentation is with discobrakes brake pads, copper free compound is my favourite - but depends on personal preferences etc.