rear disc pads keep rubbing rotors

BobbyD

New Member
I seem to have this problem after each ride, and I don't know how to fix it. I'm using Avid Elixer 5's, if it helps.

I took it to a shop already, I won't name names, and all they did was loosen my hub...thanks dicks! I took it to the shop I bought it at and they said they fixed it, but the problem is back.
 

Spylab

New Member
First, check to make sure the rotor is dead straight. If there's a particular strike spot (a la *CHING* *CHING* *CHING* as the wheel turns, it might be slightly bent. There's a special tool to bend a hop back, but you can even do it with your hand or an adjustable wrench.

If that's not the cause, remove the wheel and take out the brake pads. Use a flathead screwdriver to manually push the pistons back (inside the caliper). If you change your brake pads and don't do this, the hydraulic fluid keeps the pistons where they where, which closes in on your rotor with a set of new pads in place. It will take a little force, but you should be able to get them to retract (same basic concept as a car).

Once the pistons are pushed back, put the pads back on and the wheel back on. Park Tool has a handy shim guide for disc brakes, but you can make do with a thin piece of aluminum (like .024 or .040 gauge max). Slide these shims between each of the pads and the rotors and pump the brakes to recalibrate the pistons. You want to get things tight with the shims in place. Remove those shims, and that should provide the proper clearance for good reacting brakes without any rubbing issues.

Hope this helps.
 

TimWarchol

Scum Sucker
when they say loosen the hub them might mean by putting spacers in between the bolts... i have that problem and the gap fixed it right up
 

Carson

Sport Bacon
Team MTBNJ Halter's
First, check to make sure the rotor is dead straight. If there's a particular strike spot (a la *CHING* *CHING* *CHING* as the wheel turns, it might be slightly bent. There's a special tool to bend a hop back, but you can even do it with your hand or an adjustable wrench.

If that's not the cause, remove the wheel and take out the brake pads. Use a flathead screwdriver to manually push the pistons back (inside the caliper). If you change your brake pads and don't do this, the hydraulic fluid keeps the pistons where they where, which closes in on your rotor with a set of new pads in place. It will take a little force, but you should be able to get them to retract (same basic concept as a car).

Once the pistons are pushed back, put the pads back on and the wheel back on. Park Tool has a handy shim guide for disc brakes, but you can make do with a thin piece of aluminum (like .024 or .040 gauge max). Slide these shims between each of the pads and the rotors and pump the brakes to recalibrate the pistons. You want to get things tight with the shims in place. Remove those shims, and that should provide the proper clearance for good reacting brakes without any rubbing issues.

Hope this helps.

I fixed my Elixir 5 brake rub by pushing in the pistons and setting the pad clearance with a couple of business cards (screw Park Tools!). All better now. Seems like I have to do this every few months, regardless of pad changes.
 

BobbyD

New Member
Tim is this some sort of Polish joke I'm not getting? JK! Joking aside, they didn't use a spacer or anything, they just loosened it almost to the point that it looked and felt like it was going to fall off.

Mike and David, I was able to move the pistons back and fixed it for now. BUT...regarding setting the pad clearance, I used business cards, I barely have enough clearance to fit dental floss much less a shim or business card. Does this mean the brakes weren't installed properly? Do I have to bleed them? As much as I'd love to take it to a shop, I'm unemployed right now, so money is tight.

And thank you all for the help, it's GREATLY appreciated!!!
 

Robson

Well-Known Member
Maybe you have sticky pistons and they not move freely. I would change pistons and seals.
 

Shaggz

A strong 7
Try bleeding them. If the brake fluid comes out cloudy grey/black, there may be an internal seal that has broken down and they have to be rebuilt.
 

Carson

Sport Bacon
Team MTBNJ Halter's
Shaggz is right but clean the pistons with soapy water and a toothbrush first then lube with a tiny amount of brake fluid. Sometimes they get dirty and stick. If that doesn't work, then I'd bleed them.
 

smufguy

Member
Bobby, I had the similar problem and this is how I over came it.

1) I run Juicy 7 Ultimates (not as great as an Elixr, but it works). I had few rubs on the rotor from the time I purchased it.

2) I took the caliper out of the bracket, took the pads out along with the pad separator (that thin metal piece that goes between the pads) and I pushed the pistons all the way in.

3) Then I put the pads in and installed the caliper on the bracket. They were loose enough that I could move them at both the bolts and body of the caliper.

4) I put the bike upside down (dont have a bike stand) and hit the brakes hard enough to enable pad contact. then I did a whole 4 to 5 revolution of the rotor (by spinning the tire) while holding the brakes enough to spin it through.

5) Release the brake and spin it freely. It spun free with no scrapping.

6) I gently took two 5mm allen keys and simultaneously tightened the calipers down enough to hold them in place.

7) spun the tire to find out rubbing and hit the brakes. Repeated again and no rubbing.

8) Torqued them down and they have been beautiful for the last 2 months.
 

wyckoffcycle

Shop: Wyckoff Cycle
Shop Keep
You still having this problem??? I would say bleed it especially if it was a factory oe bleed. I don't think they pump the lever during the bleed So there is too much juice in the system causing extra expansion.

If your pushing the piston's back and it's not going easily the thing needs to be bled for sure.

I've had this issue several time's with out of the box NEW brakes...
 

BobbyD

New Member
You still having this problem??? I would say bleed it especially if it was a factory oe bleed. I don't think they pump the lever during the bleed So there is too much juice in the system causing extra expansion.

If your pushing the piston's back and it's not going easily the thing needs to be bled for sure.

I've had this issue several time's with out of the box NEW brakes...

I couldn't tell ya because I sprained both my wrists last time out so...

But I think you might be right. I'll have to take it to a shop if I have to bleed them. Something I really wanted to avoid but, oh well. Hopefully they'll be kind enough to show me how to do it for the next time.
 

skyrokz

Well-Known Member
bleeding is really easy, altough it will cost ya $40 bucks for the bleed kit, i had a similar problem and it turned out that i had a lazy piston which resulted in sram sending in a replacement rear brake, if you don't get the issue resolved after a few times have your shop contact sram and they will send a replacement, also with my new brake my mechanic installed ceramic pads which are super quiet, sometimes bleeding works, loosening the caliper mounting screws depressing the brake lever and re-tightening the bolts does it.
Most importantly keep in mind that the way we ride these bikes we are pushing them hard, sometimes a stick will get caught or you will hit your rotor with a rock or you will slightly untrue your wheel which will cause the rotor to be out of tune so sometimes you just have to be realistic and cope with the fact that shit on your bike is going to make noise and get a little f-ed up here and there.
Get a bunch of cleaners, lubes and good tools and make sure your bike is clean, lubed and greased up (not the rotors:D) and keep on pedaling

oh and by the way taking out the pads and beveling the edges slightly and resurfacing them with some 200+ grit sand paper does the trick too in some cases, run the sand paper on the contact area of the rotor too while turning the wheel that solves a lot of noise issues.
 

BobbyD

New Member
Update

Well now they're completely fuct! :(

I cleaned it out with a toothbrush and soapy water. After, I squeezed the brakes a couple times to check to see if the pistons were moving freely, and they did. BUT...one of them popped completely out. I put it back it, and now I have no brakes at all!

I can't explain how frustrated I am.

Any suggestions?
 

JB1

Member
Well now they're completely fuct! :(

I cleaned it out with a toothbrush and soapy water. After, I squeezed the brakes a couple times to check to see if the pistons were moving freely, and they did. BUT...one of them popped completely out. I put it back it, and now I have no brakes at all!

I can't explain how frustrated I am.

Any suggestions?

You squeezed the lever while the brakes were off of the bike?
 
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