Last week I asked for advice on bleeding a front SLX on which I had shortened the hoses. I tried all the advice and it still won’t bleed.
The lever feels nice and solid but won’t stop properly.
I have
1 Re-cut hose with yet another olive and insert
2 Tried a different disc
3 different pads
4 bled with caliper off bike and a thin insert to allow pistons out more
5 used gallons of mineral oil
I did the back at the same time and that was fine in 5 mins.
I rang my LBS and although they said they would take a look, you could hear the panic in the mechanic’s voice!
What can I possibly try next?

if the lever is solid feeling then you have got the air out of it and something else is wrong. contaminated pads?

I have tried 2 pairs but I do have another in my pack so I will try them next!

contaminated disc? Did you get oil on the disc?

Sticky piston? Misaligned caliper?

I wasn’t quite sure what you mean when you said that the lever feels solid but won’t stop properly, but after reading TJ’s reply I assume that the lever’s solid but not stopping the bike. If you’ve had contaminated pads as TJ suggests and fitted new ones (as you’ve mentioned you have) they won’t stop the bike properly either until they’re bedded in.

No, but there is a stunning difference between rear and front which were done at the same time with the same pads.

well if youve tried different disc and pads,then it must be somet else.

i have had similar with my shimano brakes and sintered pads. i cleaned the rotor and then went out and they were useless. lots of hard braking and bedding in and they are fine now.

Are both pistons moving freely?

Personally I’d take the disk and pads off the rear and put them on the front, see what happens. Quite faffy but you’ll learn something from it.

pop the pads from the rear in and see if it works

I’m on it !

should add that i had the problem when putting in new pads.

Did it work ok before you shortened the hose?

Are the pistons moving [much / anything] or is the lever going solid because you are compressing the fluid in the ‘slave cylinder’ behind a seized piston (rather than pushing the piston/pad out against the rotor) ?

Your comment about using gallons of mineral oil would suggest you are getting [at least some] fluid out of the nipple, which kinda suggests that the hose shortening exercise probably didn’t fatally compromise the hose, causing a restriction and a firm feeling lever – but I’ll ask anyway … 😉

Can you get fluid through the system and out down through the hose ok with the bleed nipple open, or is it the lever a bit firmer / fluid volume a bit less per-lever-pull than you’d otherwise expect ?

(Assuming SLX brakes are similar to other hydraulic systems – if not ignore all of the above 🙄 ).

I had this recently – I’d bled the front brake after shortening the hose (shimano) and achieved a nice solid lever feel. However, the brake just lacked power – with a clean disc and pads. It wasn’t improving so I took a look at the caliper and it was far from centred in comparison to the rotor. In fact the rotor was just about touching the caliper edge. I took the pads out and pushed the pistons in and feathered the lever – both pistons seemed to be free and moving but one side did come further out after a few pulls. Anyway, I reset the pistons, put the pads in and messed about for a bit getting the rotor completelty central in the caliper – problem solved. It may not be whats wrong with yours, but a simple thing to check and rule out nonetheless.

as others have said – make sure the caliper is centred over the rotor (have a look on the Hopetech site for a wee video – different brakes, same principle). Bleed from caliper up to lever, with a syringe on the bleed nipple and a jar or something to gather the fluid that spills out the reservoir. Do this with either – no pads/old pads/plastic block. Whatever way make sure you have pushed the pistons right back first. If doing with no pads don’t pull the lever 🙂

as others have said – make sure the caliper is centred over the rotor (have a look on the Hopetech site for a wee video – different brakes, same principle). Bleed from caliper up to lever, with a syringe on the bleed nipple and a jar or something to gather the fluid that spills out the reservoir. Do this with either – no pads/old pads/plastic block. Whatever way make sure you have pushed the pistons right back first. If doing with no pads don’t pull the lever 🙂

This gets 99% of the air out if bike is horizontal on a stand. If you have a spongy lever (whcih doesn’t seem to be a problem) after thsi, bleed top down – again follow the Hope vid.

If after all of that they still don’t work put in bin !