Anybody give any guidance on how to resolve my problem please?
For a while my rear brake has been problematic, I replaced the pads in thinking they were contaminated but same problems with the new.

When pulling the brake while riding there is no stopping power only screeching/squealing. Over the weekend I cleaned everything properly and gave the pads and rotor a light rub with some fine sand paper in the hope they would bed in together.

I tried to bed them both by riding quickly and braking hard and repeating for about 10/15 minutes but I could not get the rotor hot at all.

The interesting thing for this is I flipped the bike upside down and turned the pedals with my hand while the brake was on and the lever just went slack (touched the grip), once the bike was righted it took 20/30 pumps and then the lever became tight again.

During this i kept feeling the rotor for any oil or anything that might have come out but didn’t feel anything.

Anybody have any ideas, I’d be really grateful

If the lever feels different when the bike is in different angles it needs bleeding as there is air in the system. The good news is shimano are easy to sort.

I would suggest bleeding through with proper Shimano mineral oil, this is what i thought i could get around by using some LHM fluid, but it just doesn’t work i’m afraid.
You will end up with a much firmer bite and the brakes will work well after a short while. Dead easy job if you take your time, i would suggest removing the pads the 1st time you bleed them through, don’t contaminate the pads. The proper oil has the proper viscosity which they need to work properly, my brakes were exactly as you’ve described and are spot on now.
Good luck

Brilliant, thank you for that.

The bike is around a year old and I’ve not touched the brakes before really, what causes the need for them to be bled? Is it possible that a small amount of the oil has seeped out onto the rotor to cause the sound that goes with the lack of bite?

Where is the best place to get the stuff I’d need to do the job myself?

Def air (poss in the lever reservoir as it shifts when at dif angles)

sounds like the pads are ALSO contaminated so:

-remove pads
-clean rotor iso. alcohol and heat (even both sides)
– file a good couple mm off each pad until they have the same surface look as a new pad does (sand paper just isn’t man enough to get deep enough)
– next roast the pads! heat gun is ace, get them really hot!
-refit everything
-bed in the pads (brake to a stop repeatedly about 30 times, you will feel the brake force increase with each stop

epic bleed kit…

it’s unlikely that brake fluid has actually leaked out unless the bleed ports look moist…?

air expands when the fluid gets hot

also don’t forget to remove the air from the brake fluid before you bleed.

you will need either the ‘bucket kit’:
20.99 from evans full kit

or: epic bleed solutions kit

or, make your own:
bleed bucket
+oil
+hose
+any old syringe

🙂
Okay I know what I will be doing on Saturday, again thank you for the advice.
I’m going to go for the Epic Bleed Kit, and plenty of tea.
Will report back once the operation is complete.

Also I will have a closer inspection of the bleed ports, I didn’t notice anything but didn’t really have a close look. The pads are pretty much brand new so I’m surprised they are contaminated, perhaps the braking force hasn’t been powerful to actually bed them in? Even so I will do as you suggested walla and see how it goes.

Fingers crossed!

Do you by any chance run your lever really far in?