Sticky pistons: MTB disc brakes

[boemelaar_bob]

Hi guys

I'm having issues with my avid elixir CR  pistons. They seem to be beyond sticky,  to the point where they are not resetting and  make contact with the rotor constantly. 

I have cleaned them multiple times by  removing the rotors, the pads, exposing the pistons and cleaning with  solvent and string. But they're not coming right

Seeing that they are about 10 yeats old is it time to replace....or another way to clean sticky pistons?
 

Edited September 6, 2021 by boemelaar_bob
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[DieselnDust]

Don't bother, replace the brakes. Those Elixir models were especially problematic.

The Newer SRAM brakes are way better but best value for money brakes is probably Shimano Deore or Formula Cura (little more pricey but very high performance and light)

[droo]

23 minutes ago, boemelaar_bob said:

Hi guys

I'm having issues with my avid elixir CR  pistons. They seem to be beyond sticky,  to the point where they are not resetting and  make contact with the rotor constantly. 

I have cleaned them multiple times by  removing the rotors, the pads, exposing the pistons and cleaning with  solvent and string. But they're not coming right

Seeing that they are about 10 yeats old is it time to replace....or another way to clean sticky pistons?
 

Have you bled the brakes?

[boemelaar_bob]

Okay awesome. That's for that advice.

Will look into new breaks????

As a general rule...are elixir rotors compatible with other brands?

 

[boemelaar_bob]

4 minutes ago, droo said:

Have you bled the brakes?

Yes, 100s bled. No bubbles and pressure was good.

[droo]

31 minutes ago, boemelaar_bob said:

Yes, 100s bled. No bubbles and pressure was good.

Someone's got to ask the stupid questions, and it's usually me.

 

If you're not in a position to spend on a new brakeset, the next step would be to do a caliper service - pop the pistons out, carefully remove the piston seals, clean out all the gunk, apply DOT grease to everything, reassemble and bleed again. Instructions here. This should get the calipers working again for at least as long as the levers last. This is probably only worth it if you can do it yourself though.

 

Otherwise, as DND says, just replace.

Edited September 6, 2021 by droo

[boemelaar_bob]

38 minutes ago, droo said:

Someone's got to ask the stupid questions, and it's usually me.

 

If you're not in a position to spend on a new brakeset, the next step would be to do a caliper service - pop the pistons out, carefully remove the piston seals, clean out all the gunk, apply DOT grease to everything, reassemble and bleed again. Instructions here. This should get the calipers working again for at least as long as the levers last. This is probably only worth it if you can do it yourself though.

 

Otherwise, as DND says, just replace.

 Cool, not stupid question????

I tried to do that this weekend but made a critical error... I disassembled the caliper before popping out the pistons. So  pistons stuck inside the caliper  body and cant get them out. To rebleed, force them out using hydraulic pressure then disassemble and reassemble. Seems like a huge mission if they are buggered completely.

[BMXER]

A good blast with q20, they will never stick again!

[boemelaar_bob]

28 minutes ago, BMXER said:

A good blast with q20, they will never stick again!

Do they still make Q20????

[Rolf Hansen]

3 hours ago, boemelaar_bob said:

Do they still make Q20????

Hell yeah! Works amazing for removing grease from all kinds of places where you would like grease to remain.

[Hairy]

5 hours ago, boemelaar_bob said:

 Cool, not stupid question????

I tried to do that this weekend but made a critical error... I disassembled the caliper before popping out the pistons. So  pistons stuck inside the caliper  body and cant get them out. To rebleed, force them out using hydraulic pressure then disassemble and reassemble. Seems like a huge mission if they are buggered completely.

Not sure what yours look like exactly, but the motorbike guys often attach a air compressor to the fluid inlet to the caliper body and use this air pressure to pop out stubborn pistons. Make sure you leave an old brake pad in there to prevent the pistons shooting across the room and also keep your fingers clear of any moving parts.

[DieselnDust]

just remember those things have DoT brake fluid in them so not exactly lekker stuff to inhale after being aerated via a compressor

Q20 may help move the pistons but the reason they're stuck is likely because they're skew and jammed as a result. The best direction for them is back into the piston body. Apply a a bit of Dot Fluid Brake grease to the piston outer cylinder surface (Skirts) and open the bleed port at the lever. Then try to force the pistons back. If they move then close the bleed port and see if they can be pumped out by pulling on the brake lever till they're all the way out. Then its easier to grease them up and force back in again and ensure they go back straight.

Then bleed and see if they work. If not the problem is likely at the lever. and that's going to be expensive to  solve since the only way to do that for good is a new set of levers from a more modern SRAM Brake.

[FirstV8]

4 hours ago, Rolf Hansen said:

Hell yeah! Works amazing for removing grease from all kinds of places where you would like grease to remain.

The product is now owned by CRC Industries .https://q20.co.za/products/ They also sponsor a MTB team . Their Q Bike dry lube is tops .

[Rolf Hansen]

21 minutes ago, FirstV8 said:

The product is now owned by CRC Industries .https://q20.co.za/products/ They also sponsor a MTB team . Their Q Bike dry lube is tops .

Humour was intended. I always have some Q20 at hand.