Thread: Question on a Brake Bleed

I recently aquired my first Downhill bike, and got it needing a bleed. Since I've been away from CO where it was stored for the last 5 motnhs I'm now just getting to it. My question is this.

When I'm bleeding the system I kooked the hose up to the bleed valve, and then turned it a quarter or half a turn, I push the fluid into the system with a bottle, but the instead of going into the system and out through the lever, the fluid leaks out throught the threads (some if it may be going in, but most is definatly leaking out... I spent a few hours on this tonight and finally gave up. This is my first bike with discs (old Hayes system, not sure of ) so maybe I'm gdoing something wrong, but could it be that the threads are shoot or I knew a new valve? After follwing two tutorials off of MTBR and Pinkbike I think I got the right way down, but starting to loose my patience, and help is appreciated. Don't exactly have the money to take it to a shop right now, as I gotta save to ship the thing back to California, so if nothing works I'll probably just give up till next month when I'm back there.

What kind of brakes are they?

I know they are Hayes, I got the Rig on here from Melsnow and I just searched it saying they were MRP Hayes Hydro's, but that doesn't really sound right. I'm a jong when it comes to disc brakes, and there wasn't a model number clearly marked on them.

Try screwing in that valve as far as you can. Don't over do it but get it so it's snug. Then go about half a turn back from there.


If it still leaks or you've already tried this you probably need a new valve because the interface isn't sealing for some reason. I know that's not much help but I've never had this problem. I just hope that whoever had them before you didn't strip or damage the threads in the caliper.

If it BLEEDS ve can kill it.

Thanks Kidwoo, already tried getting it all the way in adn then backing it out, so it looks like that's what I'm in for.

Is english your first language?

If not, cool.

If so, you won't be able to read an instruction manual very well.

First things first, I say!



(good luck, Hayes are easy if you are delicate)

You didn't say anything about putting the catch resevoir up on the lever. I'll assume you did this, but if you didn't, thats your problem because the fluid doesn't have anywhere to go.
If you did get your catch basin set up here are some trouble shooting bits:
edit: .5. Get your setup right, caliper low, lever high, no dips in the line, you want it going 'up' to the lever. Rotate lever so its perpendicular to the ground.
1. If its a full Hayes bleed kit, poke a hole in the bottle you are using for catching the old fluid so air gets out and fluid gets in. You've gotta keep it an open system on that end.
2. Set up your catch system, then take your pads out and push the pistons back into the caliper so they are flush with the caliper body. This will help with sticky pistons as well as helping move whatever giant sticky air bubble you have. A bit of nasty, dirty brake fluid should exit the lever up into your catch system.
3. Set up your bleed valve system on the caliper.
4.With Valve open, hit your brake lever a few times. This will prbably suck some of that dirty fluid back in, and then some air into the lever, but you can deal wth that once you actually get the bleed going.
5. Unless something is royally fuct, you should be able to bleed them normally now. So make sure your bottle on the caliper end is full and start bleeding. Get a friend to tap tap-a-roo on the brake line with a screwdriver handle all the way from caliper to lever.
6. The grand finale: This where people blow it when bleeding Hayes. When you are just about finished, but still pushing fluid through, you need to turn the handlebars each direction. This will get all the air out of the lever, there are some nooks and crannies in there for air to hide.
While still pushing fluid through, close the blleed valve, then close the lever.
Clean spilled brake up with some water to neutralize the DOT and yer good.
YMMV.

Clean spilled brake up with some water to neutralize the DOT and yer good.

Now that I've never tried.

Water works better than alcohol?

Originally Posted by kidwoo

Now that I've never tried.

Water works better than alcohol?

Yup, I guess. Thats what the Avid bleed kit says anyhow. Seemed to work well for me last summer. No eaten paint.

[enginerd]
brake fluid is hygroscopic, meaning it absorbs water

one reason your hands feel so dry afterwards
its also the reason why old fluid isnt as good and has a lower BP

[/enginerd]

so yea
cleanup with water

Meh

I was going to say 'hydrophilic'

Thanks fellas. Did basically exactly what flowtron said last night, but still had flud coming out of the thread in the vavle. I'm going to try one m,ore time today, got fed up and took the whole system off the bike to try it so well see if that makes it any easier. I'm thinking I just wasn't doing something right last night, or the threads are stripped.

BTW Rideit- Technically English is my third, but I know it well enough to realize that the instructions that came with the Hayes bleed kit are shit, got a whole lot more help from online tutorials.

Originally Posted by elchupanebre4

Thanks fellas. Did basically exactly what flowtron said last night, but still had flud coming out of the thread in the vavle. I'm going to try one m,ore time today, got fed up and took the whole system off the bike to try it so well see if that makes it any easier. I'm thinking I just wasn't doing something right last night, or the threads are stripped.

BTW Rideit- Technically English is my third, but I know it well enough to realize that the instructions that came with the Hayes bleed kit are shit, got a whole lot more help from online tutorials.

Are you getting any movement at all in the fluid? Is anything coming out into the catch bottle when you are squeezing the fill bottle?
If you are getting a fair bit of fluid in the catch but leaking around the threads of the valve, don't sweat it. If the brake was in bad shape to begin with you'll have to bleed it a few times anyhow.

Originally Posted by flowtron

Are you getting any movement at all in the fluid? Is anything coming out into the catch bottle when you are squeezing the fill bottle?
If you are getting a fair bit of fluid in the catch but leaking around the threads of the valve, don't sweat it. If the brake was in bad shape to begin with you'll have to bleed it a few times anyhow.

Very true.
If it seems backed up, an air compressor blowing through there will amaze you with the shit that comes out of your lines.