Bicycle Mechanics - spongy brake levers after replacing pads

hi guys! i just bought a new focus hybrid with tektro draco hydraulic brakes. everything worked great but the brakes sounded bad (metal on metal unpleasant noise) with the stock pads so i switched the front brake out with a kool-stop pad. i followed the instructions on the manual / some youtube videos - removed stock pads, reset calipers by pressing into them, insert new pads, install wheel, "bed-in" calipers by squeezing brake lever 30+ times, and finally adjusted pads to rotor by unscrewing break & tightening lever while screwing it back in. The manual says the pads require 30-40 full stops to achieve optimum breaking performance, which i think i did.

After i pull my break lever 15 times it seems to go back to the correct behavior but soon after it just becomes as spongy as before, the lever going almost all the way to the grips. its not effective at all compared to my back brake which i didn't change out.

Did i miss a step? Or does it take a really long time to "bed in"? this is weird for a new product. :twitchy:

It sounds like you have gotten air into the system and it needs to be bled out. Here's a video from Tektro which shows how to do it. https://www.youtube.com/watch?v=LhKKe6av-0U It is important that your brakes are in top shape, if you are not confident doing it you might want to consider taking it to the bike shop and asking if yoiu can watch it being done.

Thanks for the reply! It seems simple enough to do it myself. I'll get a kit, try it and see if it changes. Thanks!

Make sure you use the right fluid - at a quick google Tektro seem to use mineral oil (i.e. not DOT 4 brake fluid) but you must check - often the fluid type is printed on the reservoir lid. Wear eye protection - if you don't have goggles then wear your cycling glasses. Good luck.

Did i miss a step? Or does it take a really long time to "bed in"? this is weird for a new product.


it is hard braking in motion, not on the repair stand, that mates the new disc pads to the rim.

Make sure you use the right fluid - at a quick google Tektro seem to use mineral oil (i.e. not DOT 4 brake fluid) but you must check - often the fluid type is printed on the reservoir lid. Wear eye protection - if you don't have goggles then wear your cycling glasses. Good luck.

yeah i just bought the tektro bleed kit. it's mineral oil for sure. it's misleading because 10% of the bleed kit's labeled as being Tektro Bleed Kits have the metal outlet valve that attaches to the caliper valve (as shown in the video you linked). the other 90% don't have that which has annoyed some commenters on utube. i'm sure i got the right one. EDIT: actually the tektro draco brakes don't need the screw-on valve like the auriga brakes. it seems you just slip the tube on the dracos. simple


it is hard braking in motion, not on the repair stand, that mates the new disc pads to the rim.

are you saying that braking while riding will set in the pads better? that makes sense because the brakes are being used in their prime setting. even doing that the brakes are spongy so i must have gotten air into the system somehow. maybe it's because i pressed too hard into the calipers to reset them before putting the new pads in. how much do you press onto the calipers to reset them?

the auto pad wear function of hydraulics mean,
you should Always put the Keeper in the caliper,
when you remove the wheel.
new disc pads mean the caliper piston has to be spread out again..

read the manual as to how to do that.

On my Car I got a big screwdriver and pried the slave cylinder pistons out.
then put the new pads in.

okay i bled the brakes and it fixed the spongy problem! that's great! the crappy thing now is i got mineral oil on my pads and rotors and now it squeals really loudly when i break. the instruction video should have told me to take the pads out before bleeding so i don't soak them with oil. how disappointing!! i called a lbs and they said i can either get some brake cleaner at a local car shop or i'll have to replace the pads (which is a waste of money). i heard Squeal Out brake cleaner works but i'm not sure if it will help this situation.

do you guys have any experience with this?

Actually, i found this to be very helpful for contaminated pads: http://steveukmtb.wordpress.com/basic-cleaning-and-maintenance-guide/brake-and-rotor-cleaning/

So nothing will help the contaminated pads. I just replaced the pads, cleaned my rotors with rubbing alcohol and everything works great! It sucks that the tutorial didn't mention that it would be wise to remove the pads when bleeding because oil can seep out of the valves and such.