why are my hydraulic disk brakes so bad?

[Black Sheep]

I built my mountain bike in 2006 with Deore hydraulic disk brakes and they worked great

The bike was in fairly regular use for a number of years until about 2011 when, for various reasons I stopped riding.

In the past couple of years I've been using it again but the brakes are crap, they just don't hold it on a steep hill, they'll slow me, and they'll keep me there when stopped but they won't bring me to a stop!

I've replaced the pads, I've had them serviced (and told there's a bit of grit somewhere in the rear calliper or hose making it tricky to bleed, but it's bled and works)

To me, they're acting as though the pads are glazed, but roughing them up a bit only sorts it for a ride or two.

Any ideas?

Ta

 

[Gunk]

Firstly I would just try cleaning the disks with brake cleaner and wire wool. Personally I’m not a fan of older Deore brakes, they just don’t seem to have a lot of feel. If you can’t get them working properly just swap them for something better, I’m now running Sram TLM’s they’re in a different league.

 

[mrandmrspoves]

If 'roughing up' the pads improves performance then the problem has to be the braking surfaces. Give the rotors a really good clean and rough up the pads at the same time. If the improvement is still short lived you could replace pads AND rotors - but bearing in mind the age of your current brakes it may just be time to bite the bullet and replace the entire set.

 

[Ming the Merciless]

So a 7 years gap where you didn’t ride bike. Have you bled the brakes since you started riding again?

 

[iluvmybike]

Prob worthwhile replacing the brake fluid after all that time?

 

[Black Sheep]

I should have clarified, the've had fluid replaced and been bled.

 

[Deleted member 26715]

Any leaks, if not it will be air, assuming that a piston is not seized, are we talking front, back both?

 

[Crankarm]

It's disc not disk.

 

[GuyBoden]

With advice from this forum, I cleaned then sand papered my discs, fitted good new brake pads and bled the system. My brakes have improved a lot.

 

[Deleted member 26715]

It's disc not disk.

Who cares, oops clearly you, get over it.

 

[fossyant]

I'd clean the rotors thoroughly, and replace the pads. They get contaminated, and roughing up will only work for a few rides. Had this on my wife's MTB. I serviced the brakes, new pads, discs cleaned. But during a few months of storage, the discs contaminated (most likely as the bike was near mine as I was doing maintenance, and may have contaminated the disk with over spray of oil/silicone/etc. Brakes acted as they were glaized, scrubbed them up, worked for a few miles and back to square one. Binned the pads, cleaned the discs and no problem since. The bike is now stored hung up out of the way of me cleaning mine.

Worth having disc brake cleaner in the supplies - regularly give my discs and pads a quick squirt.

 

[Levo-Lon]

Bikes obviously fooked, you need a new in

 

[Globalti]

If the brakes judder and squawk as the bike rolls to a stop they are badly contaminated with oil or brake fluid.

 

[Black Sheep]

I do get some squawk from the rear but not the front.

I do agree with Levo-Lon that the bike is old and needs replacing, but, having been built in 2006 it's the youngest bike I own (1970 and 1968 for my two road bikes, both of which are broken... Perhaps I should give up on this cycling lark )

 

[glasgowcyclist]

My bike developed the same symptoms and after replacing the pads and discs several times it turned out to be slightly leaking calipers contaminating the braking surfaces. New calipers fixed it.