Bicycle Mechanics - Time to learn to work on Disc Brakes?

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Peek the Geek
09-11-05, 10:53 PM
I do most of my own bike maintenance now, except I haven't really learned how to work on the disc brakes on my mtb. I'd like to get some help on doing so now, though.

I needed to shorten the front brake hose a few weeks back, but I didn't have whatever I would need to do so, so I took it to my LBS. When I got the bike back, the front brake lever was way too soft, almost reaching the bar when I'd brake, so I took it back to the LBS to have them readjust it. Now, it's still a little too soft for the most part. Sometimes, though, the lever will brake pretty stiff at first before going soft again.

From what I've read, I'm guessing this might be a bad bleed(?) Does this sound right?


MudPie
09-11-05, 11:16 PM
What kind of brakes do you have?

If the brake levers feel soft, then it's probably a bad bleed. There is still air in the system, and air being much more compressible than the hydraulic fluid, it will give you a spongy/soft feel. You can probbly bleed them yourself.

Also, you might want to check for any adjusting screws that regualte lever travel. I have a set of Hayes Nines and the screws seem to be notorious for backing out, allowing the lever to travel farther before adequate system can be developed.

Peek the Geek
09-11-05, 11:49 PM
What kind of brakes do you have?

If the brake levers feel soft, then it's probably a bad bleed. There is still air in the system, and air being much more compressible than the hydraulic fluid, it will give you a spongy/soft feel. You can probbly bleed them yourself.

Also, you might want to check for any adjusting screws that regualte lever travel. I have a set of Hayes Nines and the screws seem to be notorious for backing out, allowing the lever to travel farther before adequate system can be developed.

I've got Hayes HFX-9s. I ride mostly road, so these disc brakes are a new animal to me.

I was guessing it wasn't an adjusting screw problem since it showed up right after the LBS did a bleed and since the lever sometimes feels extra firm before going spongy (i.e., the feel isn't constant).

So, what would I need to do a bleed myself?


Stannian
09-12-05, 05:05 AM
A hayes bleed kit and the owners manual does a pretty good job of explaining how to do it.

135crewchief
09-12-05, 02:38 PM
i have Hayes and my adjusting screw also keeps backing out. Which makes the brake lever almost bottom out before it response. But after every ride i will readjust it and it is fine. I was told to put some locktite on it, but i haven't yet.

WD_40
09-12-05, 04:15 PM
i have Hayes and my adjusting screw also keeps backing out. Which makes the brake lever almost bottom out before it response. But after every ride i will readjust it and it is fine. I was told to put some locktite on it, but i haven't yet.

Yeah, I have the same issue. Hayes knows about it and some of their latest offerings have been redesigned to eliminate that problem.

I put some loctite blue on my adjustment screw, but I haven't been on the trail since then to test it out.

135crewchief
09-12-05, 07:29 PM
Let me know if the locktite works or not

Pocorider
09-12-05, 09:59 PM
Man I have the same problem too. It is the most frustrating thing. One thing about the loc tite is if it gets on anything else such as the push rod, the lever will feel like crap and wont work properly. One suggestion I heard was to use a toothpick to apply the loctite.

MudPie
09-12-05, 10:28 PM
Man I have the same problem too. It is the most frustrating thing. One thing about the loc tite is if it gets on anything else such as the push rod, the lever will feel like crap and wont work properly. One suggestion I heard was to use a toothpick to apply the loctite.

The Loctite works - I used the "blue" (medium strength version) and it works dandy.

Correct, don't get Loctite on other pieces of hardware.

Here's what I found works best:

1 - turn adjusting screw counterclockwise to expose as much thread as possible.
2 - use toothpick or nail and dab a little Locktite on the exposed threads
3 - turn adjusting screw clockwise to desire position (this action drags and helps distribute Loctite along the threads).
4 - let it set