Mountain Biking - Disc Brake Noob - Do's and Don'ts

Searched the forums, park tools and sheldon brown and couldn't really find what I was after - my apologies if it has already been covered and I just didn't look hard enough.

Anyway - just got my first mtb with hayes hydraulic disc brakes and was looking for some do's and don'ts regarding use and maintenance. My lbs tells me not to ride road when wet because the oil from the road will contaminate the pads. What about cleaning and lubing the bike? I normally spray all the moving parts down with aerosol silicone and then wipe off as my last step. If the silicone gets onto the pads will it ruin them? What about de-greasers - will they hurt the pads? What about adjustments? How do I know when the pads/rotors are worn to the point of replacement.

Any other pointers or advice will be greatly appreciated.

Thanks
C.

My lbs tells me not to ride road when wet because the oil from the road will contaminate the pads.


Now that's just paranoid. Unless your area roads are one big oil slick, the whole point of disks is the same stopping power in all weather. Are the guys on motorbikes scared of the rain too? If there is really that much oil on the roads, I wouldn't ride on them at all.

They told you what?

Did they also say not to ride on dusty trails and to avoid greasing your hubs?

also lubing the bike everytime is kinda over the top .
there is actually some oil on every street ,thats why it is most dangerous to ride when the rain just started ,and before some of the oil is washed away.i wouldn't worry about it though.
actually yes i am scared riding my motorbike when it rains,bad idea in general ,but not because of oil .

I have a Hollywood rack in my truck. I pulled up to an icehouse for a post ride beer. The Harley boys noticed my disc brakes. They were in miffed that they were hydros. One of them decided to reach up and press the brake lever, and picked the front lever. Had to rebleed the brake after the first ride.

Whenever I transport the bike, I slide the orange tab between the pads.

Oh and the guy did apologize to me. But his buddy pointed something out that made that moment more priceless. Turns out Mr' lever puller is a Harley mechanic.

Just to show how little I know about hydro disc brakes - why would someone pulling the lever w/o the wheel assembly in place create the need to re-bleed??

Just to show how little I know about hydro disc brakes - why would someone pulling the lever w/o the wheel assembly in place create the need to re-bleed??

My bike was mounted to the rack, front tire was not on. So when he pulled on the lever the calipers pressed out with no rotor to stop them. I treated this like I would if its a car. I have bad luck with disc brakes being pressed with no rotor, be it bike or truck.

Just to show how little I know about hydro disc brakes - why would someone pulling the lever w/o the wheel assembly in place create the need to re-bleed??

you pop the piston out of it's bore, releasing fluid and creating an air bubble. not fun.

I was doing brakes on a car once and had the left side rear rotor out and had moved up to the front, I asked my girlfrind to start the car & trun the wheel. long story short.... she mashed the brake instead of the clutch and the rear piston fell out & hit the ground. :(

Anyway - just got my first mtb with hayes hydraulic disc brakes and was looking for some do's and don'ts regarding use and maintenance.
which hayes hyrdos do you have? i ask because the hfx9s have had some problems that are easily fixed but kind of annoying to have to deal with. if these are the brakes you have, make sure to do the following:

1. get some blue loc-tite and put some on the adjuster screw. adjust the levers to where you want them and then lock them in place with the loc-tite. this little bugger is notorious for coming loose, giving your brakes a spongy feel.

2. put some duct tape or something like that over the master cylinder cap. for some reason they cheaped out and used some crappy plastic plug instead of a screw. these things have been known to pop out at the most untimely instances causing you to lose your brake fluid and braking ability. strapping some duct tape over the cap is a quick fix to what could end up causing some serious problems.

i wouldn't worry too much about riding when it's raining. i've done that a few times and never have had an issue with my pads being contaminated. if they do though, they're pretty easy to fix - and if not, then you can always just get new pads.

about the levers being squeezed when the wheel's not in place, i've never had to rebleed my brakes whenever i've done that accidentally. usually a flat screwdriver will do the trick. just wedge it in between the pads carefully and wiggle it around a bit until the calipers pop back into place.

other than that, try not to get anything onto the rotors; stuff like oil, grease, even oil from your fingers can contaminate the pads. clean with either dishsoap and water or rubbing alcohol.

you pop the piston out of it's bore, releasing fluid and creating an air bubble. not fun.


I didn't know they work like that. Last time I accidentally pressed my brake lever on my front XT hydro, and the pads were completely touching. I used a screw driver to pry the pads apart. I know that does damage the pads, but does it mean I have air in my brake line now???

From my little knowledge of brakes, if the piston does not move all the way out, it usually doesn't create any problems with air bubbles. Just sort strange :eek:

If yall have been just prying the pads back, and no probs...well I guess I went overboard. LIke I said I treated the situation like I would for my truck, and with the thought of can't be just careless with the brakes.

My lbs tells me not to ride road when wet because the oil from the road will contaminate the pads. Applesauce, pure unadulterated applesauce. That's so far beyond wrong it's not funny. One of the primary reasons that disc brakes are so effective is the fact that they are OUT of contact with road contaminates
I normally spray all the moving parts down with aerosol silicone and then wipe off as my last step.Not anymore you don't
If the silicone gets onto the pads will it ruin them?If it gets on the pads OR rotors you've got some cleaning to do. DON'T TOUCH THE ROTORS with your bare hands. The oil from your skin will contaminate the pads leading to squealing and decreased performance. If you should have to touch them use denatured alcohol to clean them
What about de-greasers - will they hurt the pads? DEANATURED ALCOHOL ONLY anything else has the potential to be a bad thing
What about adjustments? How do I know when the pads/rotors are worn to the point of replacement.
You'll know.

I didn't know they work like that. Last time I accidentally pressed my brake lever on my front XT hydro, and the pads were completely touching. I used a screw driver to pry the pads apart. I know that does damage the pads, but does it mean I have air in my brake line now???

From my little knowledge of brakes, if the piston does not move all the way out, it usually doesn't create any problems with air bubbles. Just sort strange :eek:


I guess it depends on how thick the OEM rotor is. Bike rotors are prety thin so I would think most wouldn't be harmed by this.

If you have air in the system you would know. the levers would fade and you would have seriously weak stoping power that faded to none, and or you would need to pump up the brakes to even stop at all.

1. get some blue loc-tite and put some on the adjuster screw. adjust the levers to where you want them and then lock them in place with the loc-tite. this little bugger is notorious for coming loose, giving your brakes a spongy feel.

2. put some duct tape or something like that over the master cylinder cap. for some reason they cheaped out and used some crappy plastic plug instead of a screw. these things have been known to pop out at the most untimely instances causing you to lose your brake fluid and braking ability. strapping some duct tape over the cap is a quick fix to what could end up causing some serious problems.


about the levers being squeezed when the wheel's not in place, i've never had to rebleed my brakes whenever i've done that accidentally. usually a flat screwdriver will do the trick. just wedge it in between the pads carefully and wiggle it around a bit until the calipers pop back into place.




first of all for a quick fix the blue locktire works but send hayes and email and they will send you a nylock insert and youll never have a problem again.

second the brakes i have(HFX-9s), have screws to hold the cap on the master cylinder. if you mean the little rubber cap on the calipure that doesnt matter unless you open the valve to bleed your brakes.

and third if you do push the pads together, take the pads out and then carefully push the pistons back in with a small closed end wrench. to prevent this ask your dealer if they have any little hydro brake stopper piece of plastic thingys (very technical term eh) or you could just stick a piece of folded cardboard in them, this is how some manufactures send their bikes.

first of all for a quick fix the blue locktire works but send hayes and email and they will send you a nylock insert and youll never have a problem again.

second the brakes i have(HFX-9s), have screws to hold the cap on the master cylinder. if you mean the little rubber cap on the calipure that doesnt matter unless you open the valve to bleed your brakes.

and third if you do push the pads together, take the pads out and then carefully push the pistons back in with a small closed end wrench. to prevent this ask your dealer if they have any little hydro brake stopper piece of plastic thingys (very technical term eh) or you could just stick a piece of folded cardboard in them, this is how some manufactures send their bikes.
never heard of the nylock insert until now. guess i'll send 'em an email tonight and see if they send me the piece.

i have hfx-9s also, and i'm not speaking about the rubber cap on the caliper. i'm not sure how new your brakes are, but mine and a number of other people i know that have the brakes have a black plastic piece on the master cylinder that is held on by screws. in the middle of that, just beside where it says "dot 3 or dot fluid" you'll see a small round plastic cap. this cap has been known to pop out at unopportune times causing brake fluid to spray out. it's happened to a buddy of mine who i DJ with so i know i'm not just making it up.

you can't see it too well in this picture, but the small round cap i'm talking about is under the strip of duct tape to the right of the lever pivot that you can barely see in this picture:

http://www.dropmachine.com/media/data/500/1687PICT0028.JPG

My friend with a specialized hardrock disk decided that putting petrolium jelly on his already weak brakes would make the bike easier to ride. I seriously had to hold myself from laughing.
And here is another no brainer question for all you hydro guys, how hard is it to bleed the brakes? Does it take long, and what are the steps?

ya my brakes are 05s and the master cylinder body is a bit different

you should buy fundimentals (DVD) it shows you how do do many many things with you bike(everything to do with disk brakes, installing headsets derailure adjustment/instalation....) and bike techniques.(lots of stuff) i think mael did a review on it a while back. mabey do a search.

My friend with a specialized hardrock disk decided that putting petrolium jelly on his already weak brakes would make the bike easier to ride. I seriously had to hold myself from laughing.
And here is another no brainer question for all you hydro guys, how hard is it to bleed the brakes? Does it take long, and what are the steps?

To me, its not very hard. It helps to be mechanically inclined. If you have no idea what you are doing, then it may seem a little intimidating. The best way to learn is to have someone show you how to do one of the brakes, and you do the other.


The way bleeding works is like this: There is an air bubble or air in your brake line, so you want to push it out. Depending on the brake manufacturer, the fluid is pushed from the lever down, or from the caliper up. What kind of brakes do you want to know how to bleed? The manual covers it pretty well.




and third if you do push the pads together, take the pads out and then carefully push the pistons back in with a small closed end wrench.

If you do this, be careful on the Hayes hydros... the pistons are ceramic. If you arent careful, the wrench can chip the ceramic part of the piston. I use plastic tires to avoid this.