why are my hydraulic disk brakes so bad?

[Drago]

The Shimano mineral oil lasts better than DOT fluid, but it'll still need replacing after so long. When you deglaze the pads (or just fit new ones - for what they cost why faff about?) you need to deglaze and then degrease the discs as well.

 

[Globalti]

Put all the bits in the dishwasher, there's nothing hotter or more caustic for effective degreasing. Not aluminium though as the surface will be pitted by the causticity.

 

[Gazjacko]

Who cares, oops clearly you, get over it.

No! Standards shouldn’t drop, their’s/there’s/they’re just no excuse :-)

 

[SpokeyDokey]

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[Black Sheep]

It appears that the calliper is pushing the rotor across slightly, but taking the spacer between rotor and hub out doesn't solve the issue, just moves it across the other way somehow!

 

[Deleted member 26715]

Do you need to add a spacer/washer not take one out?

 

[CXRAndy]

If you've, cleaned the rotors, changed pads and fluid, if its still poor braking performance. Look at the levers and hoses, given its sat unused for many years. It could be seals have become leaky

 

[Black Sheep]

The brakes had a service recently so I would assume them to be ok with regards leaks etc.

I've adjusted the front calliper and it's sat more centrally, cleaning the disk has got more power to the front,

The rear however, having cleaned it and given the pads a scuffing only cured it for part of the ride, it's back to being an audiable warning device, but does give more performance than it did so might go another round of cleaning on it.

 

[Deleted member 26715]

You don't use something like GT86 on your chain or parts do you, if you do it's important that you cover the disc to stop over spray getting on it & contaminating the disc & more importantly the pads, only real cure is new pads

 

[Drago]

I'm afraid you're weeing in the breeze here. We can't assume that the person who worked on the brakes recently was competent or that they didn't make an error. If degreasing and deglazing the discs and new pads doesn't do it, then you're probably best off taking it to a competent spannerman (or woman).

That generation of Deore's could by troublesome. One of mine stopped working entirely for no reason, some kind of internal failure of the valving or seals in the master cylinder. People prattle on about the wonders of discs brakes, but seem to forget that when they do go south they can often be a real mare to sort, if indeed it's even possible to sort them at all (my Deore's could be stripped to that level so had to be binned).

Good luck.

 

[CXRAndy]

The brakes had a service recently so I would assume them to be ok with regards leaks

I mean the internal seals could be letting fluid by, reducing their ability

 

[Mark pallister]

Best way to clean discs and pads is with a small blowtorch I find
use on both sides of disc and face of pad when it’s cooled ,light sand then spray with isopropyl alcohol