You are hereForums / By Discipline / Mountain (off road) / MTB Gear / Break pads to close
Break pads to close
Hi all,
Last weekend I had to remove my front wheel to load the bike on a friends' car and for some obscur reasons my brake pads are now two closed and slightly touching the disc. I am quite a newbie on hydraulic stuff but after reading posts on forums, I've managed to push back the pistons and the noise disappeared ... But when I brake again, the brake pad didn't return to their original position and I could still hear the noise...
The brake system was well adjusted before, and I really think something slightly move over the weekend but can't say what.
If the piston doesn't come back, does it mean air bubbles came in the system ?
Do you think I have to do the purge ?
I have trek6000 with a juicy (3 or 5) from avid.
Any comments or help are welcome.
Cheers
Pierre
- Login to post comments
- Bookmark & share
Hey man
I had similar problems with my avid elixir brakes when I got my new bike. Google "Avid hydraulic brake setup" you should find a pdf that explains the different ways to adjust the brakes. If you brakes have the Tri-align calliper positioning system (I think they all do but check first) it is pretty easy to fix. Loosen the two bolts that hold the calliper to the forks just enough so the calliper can move. Spin the wheel and grab the front brake real quick. This pulls the calliper into the right spot (you can do it a few times to be sure). While still holding the brake lever on re-tighten the two bolts and your done. I did it to both of my brakes and it worked a treat. I have read that things like heat over time and the tightness of your wheel quick release can effect the position so you may have to redo it every now and then.
Chris
You haven't bent the disk slightly have you? Does it rub constantly or just a bit each revolution? Also you might have a sticky piston. The pads should both recede slightly when you let go of the brake. Sometimes one doesn't, and rubs.
Ok I'll try this tonight... But how the caliper could become misadjusted only by removing the front wheel ? something i don't understand...
For sure I haven't
I am sure about that because I had my ride, load the bike on the car, drive to the station, and that when the issue appears.. No ride between.
if you pull the brake lever when the wheel is out, the pads will get closer togetherr. Take the pads out, get a flat object (steel ruler works well) and pry the calipers apart till they are flush with the body of the brake. Simple as that. (small spanner works well also)
You may have just accidently squezed the leaver a little. thats all it takes.
I did try that (with the brake pad in) and the noise disappeared but when I used the brake again, the break pad remains too closed to the disc, and the noise appears again.
I have the same thing with my juicy 3 brakes. Every time I take off either the front or back wheel, I have to reset the calipers.
I do the same as was mentioned above (loosen bolts, spin the wheel, hold brake lever and retighten). It sometimes still catches and then it's a case of loosening each caliper bolt and adjusting each end individually. Sounds a ball ache but it's not too bad.
When I asked my LBS about it, they told me it's because the wheel goes back in the frame in a slightly different place each time and the brakes are low end so it takes a bit more messing about to re align them.
thing is, it is very difficult to fully iliminate brake rub, if the rub doesn't slow down the wheel spin a great deal, it will likely have very little impact upon your riding. If it is a regular thing (ie, happens a ride or 2 after resetting it), you may need a brake bleed. Also, cheaper brakes are often more prone to brake rub (generalisation of course). Best investment you can make is in a high quality set of brakes, discs and pads, as well as wheels.
Also, best to not reset the calipers with the pads in. Pads are pretty soft, if you scar the brake pad they will likely crumble apart (pending the compound). Always pull the pad out.
it happens to all avid brakes, to fix the problem replace them with Shimano, its the only solution
we need a like button on this forum!!!!!!!!@Decy
Ok got it ! I may try first to reset the caliper and then will see how it is ... i ll tell you tonight.
hopefully I don't have to remove the front wheel quite often on my usual roof top bikerack (thule 591 pro ride)
On top of that I was keen to buy the avid bleed kit. Not cheap but I've read the the universal one are not good enough... Any advice ?
The bleed kit by Avid is excellent. Dont bother with the universal one. Avid brakes are really tempramental. I find myself often having a bleed on a weekend to keep things lovely.
Dont fear the process of bleeding - a lot of people are daunted by it, but nothing can go wrong - even if you piss fluid out, you can always put it back in. The best way to learn with these things is to just fiddle with it for a while. Once piece of advice though, buy some brake cleaner (in an aerosol) from Supercheap auto - you will get fluid everywhere on the first go, so be ready with the spray and a rag. Also - dont get fluid on the pads.
The instructions that come with the Avid bleed kit are very detailed. You'll be fine, and by the end a much better bike mechanic.
Re your previous post about it being different since the bike rack - most has been covered above. The one thing I would add would be to look at the fork drop-outs to see if being in the rack has caused any paint to flake or if you have collected any paint or coating from the rack itself. If either of these things have happened, then the wheel wont sit in the same position as before. Use a small nail board (borrow one from Mrs Runo) and just go around the inside of your drop-outs.
you can always find a small spacer that fits between the callipers. When you have to remove the front wheel (chich happens quite a bit) you can shove the spacer in so that it doesn't matter if you accidentaly squeeze the lever.
^ True
Use a spacer, although shoving coins into the slots also would work well too if you front wheel is off.
hey runo you are welcome to borrow my avid bleed kit if you like, save you buying it for a one-off. assuming you live around northern sydney somewhere and you don't mind me helping you with the job (so that i nkow you don't wreck it).
alternatively you could add an avid bleed kit to my jensonusa online order to get free postage (see my forum topic created a few days ago). much cheaper from jensonusa than LBS
my Avid bleed kit came with brake pad spacers ,I use them all the time when transporting with wheels removed
any good blocke at a bike shop will also throw a couple plastic spacers your way for free if you ask nicely (they have millions lying around from transport/assembly of new bikes)
Had a flat on the front of my bike, after fixing it the disc was rubbing badly on the pad. Took it back to the bike shop where they recalibrated the Shimano M505 calipers.
They said this is very common and they recalibrate virtually every time they have the wheels off their own bikes. So I had them show me how its done so I can DIY next time.
Thanks mate, appreciate the offer.
I am looking to buy something else too to upgrade my tora tk fork so I may combine all the purchses together.
Cheers
Pierre
Hi all,
to who may have the same issue, the solution was to do what was described previously in this post. I redo the caliper adjustement, and it is all done now ... Nevertheless I may have lose a bit of efficiency in the brake so I probably have to remove bubble from the hydraulic system...
Thanks to all of you guys
Pierre
Had heaps of trouble last night replacing the rear brake pads. The calipers took ages to get all the way in.... They just didn't want to move to the point where the disc wouldnt fit between the new pads. I found using a spanner better than a flat head screw driver. Guess it has more surface area.
Even when the calipers were flush and the disc would go between the pads they were rubbing as though I was holding the brake on 50%.
What I ended up doing was rubbing the new pads on the concrete garage floor. Yeah it reduced the life of the pads but after 30 seconds per pad it all slipped in and spun perfectly.
Any suggestions for what I was doing wrong?
There could be too much brake fluid in the system. You need to release a little bit. If you've filled up the fluid system while the brakes are in a worn state it might be too full when you try and squeeze new pads in.
I'd say you didn't remove the reservoir cover before you attempted to push the piston back in. And that's what caused all the dramas.
The reservoir cover should be off until you have the pads in the caliper and the pads spaced adequately from the disc.
cheers.