disk replacement

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
ok, so what gives? is there some trick i don't know? i got the pads in just fine but the old ones were so shot that there's no room for the disk to spin w/ the new pads. is there some adjustment that i'm missing? i know this is a real basic question but any help would be great. thanks!
 

pinkshirtphotos

Active Member
your pistons are pushed out. take off your pads and use a screw driver to push your pistons back. then put in a 8 or 6 mm alan (whatever is tighter fitting) and squeeze your brake till the piston holds the alan. put pads back on that should work. ive done this a few times
 

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
ahhhh! ok, i'll give that a try.

btw, they are hayes nine. i'm pretty sure they're self adjusting though.
 

J-Dro

Well-Known Member
Hydraulic brakes self-adjust as the pads wear down. But when its time for new pads, you have to force the caliper open again. This is totally normal. Just like on your jeep.
 

ArmyOfNone

Well-Known Member
be sure not to pull the lever w/o the disc in between. That could be disasterous. Or an allen as well i guess
 

stb222

Love Drunk
Jerk Squad
be sure not to pull the lever w/o the disc in between. That could be disasterous. Or an allen as well i guess


be gently with the screwdriver too, you don't want to chewy the piston up, you can also put th old pad back in and wiggle the flat head between the old pads, this will avoid damge to the pistons
 

ytc100

New Member
Be really careful to not bend the post in the middle of the piston. I use the end of a 10mm wrench and very carefully push those pistons back into their bore. They can be hard to push and are not the most durable things on the planet so be careful!
 

Norm

Mayor McCheese
Team MTBNJ Halter's
Use a big saw. All the cool kids are doing it. :) My Avid Juicy 5s often self adjust too close and end up dragging too much. Not a problem on dry days but if there's any mud whatsoever it happens almost without fail.

When I bought the bike the shop said to always carry a screwdriver with you in case you hit the brake lever with the wheel off. Well I tried this once and learned how much a screwdriver blade chews up your pads. Now I use a saw to wedge in there and gently rock it back and forth. I imagine an old disc would be good to have and much easier to carry around than a saw. Slide it in and rock it back and forth.

I'm sure this method wouldn't be endorsed by Leonard Zinn but it works.
 

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
yeah, well, zinn's book doesn't mention crap about the pistons. i'll have to look at it b/c in addition to the wicked rub, i have zero throw in the lever. i mean zilch. hopefully pushing the pistons back will work.

btw, i used the screwdriver method prior to posting. i at least knew that much.
 

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
well, the calipers aren't cooperating at all. pushed them flush and they pop back out. i wanna get a quick ride in so i'm gonna put the old pads back in and deal for one more ride. any other ideas other than:

a) i'm an idiot, or
b) marty's sold me the wrong hayes pads???

i have no clue.
 
S

Stan LeCupp

Guest
Jake

When I replaced pads on my Avid's I had to bleed the system to remove some of the access fluid. Too much fluid in the system will cause the pads to drag, well on Avid's it does.
 

Shaggz

A strong 7
My rear brake needed a combo of bleeding and piston compression when I changed both the rotor and pads. These are the Hayes 9, same as yours.
 

ytc100

New Member
well, the calipers aren't cooperating at all. pushed them flush and they pop back out. i wanna get a quick ride in so i'm gonna put the old pads back in and deal for one more ride. any other ideas other than:

a) i'm an idiot, or
b) marty's sold me the wrong hayes pads???

i have no clue.

The clearance will be very close even with the pistons all the way back in their bore. Push the pistons back into their bore, install the pads, find something not metal to wedge in between them, squeeze your lever a few times. Install wheel. Squeeze lever again, it should feel soft for the first pull or 2 and hopefully settle into the right place. It's likely that if your rotor is even slightly bent you will have rubbing and need to straighten it. As StanLee mentioned you may need to let a drop of brake fluid out of the system as well. Are we having fun yet?
 
S

Stan LeCupp

Guest
If you do bleed the brakes yourself put the old pads in while bleeding. You don't want to get fluid on your new ones. Also put a wedge between them to hold the pistons back.
 

CycleBoy

Sussex Bike and Sport
Shop Keep
Hayes HFX 9 eh? Ok, I'm assuming that the pistons won't even push in all the way. Sometimes the system gets pressurized. Chances are you might need a bleed as well, but here is something you can try. First, take your pads out. Next, loosen your lever and point in upwards so that little bleed plug is pointing straight up. Pull that plug out, but be careful. You don't want to rip that rubber bladder in the reservoir. Go ahead and wrap a rag around the lever and that bleed hole. If you can get a box wrench in the caliper, that's the preferred method. Use either an 8mm or a 10mm. If you damage that post or the piston, you're going to need more parts. What you need to do is slowly work those pistons back in. Slowly is the key. As you push, fluid will come out of the lever. Once you have pushed them all the way in, put the plug back in the lever. Clean all the fluid up and put your pads back in. Put the wheel in and try it out.
I have done this a bit at the shop. However there are the times that the brake needs a full bleed. Just figured its worth a shot and might save you a trip to the shop.
 

bonefishjake

Strong like bull, smart like tractor
Team MTBNJ Halter's
thanks all. i ran the old pads today b/c i wanted to ride but i'll work on it again tomorrow. the brakes have NEVER been bled so they're probably due.
 

hardtale70

She's Gone From Suck to Blow
Shop Keep
There's an empty stand and full toolset just sittin here at AOA waitin for ya to show up dumbass!
 
Top Bottom