Bleeding brakes. HELP!!!!


21 replies to this topic
  • Secks

Posted 05 February 2004 - 03:27 PM

#1

I am having one hell of a time bleeding my front brakes. I have been through the regular squeeze the lever, loosen the bleed screw, tighten the bleed screw, pump up the lever routine. The problem is that once I let the pressure off with the bleed screw, i can pull the brake lever 10,000 times and I don't get any pressure. If I pull the lever, open the bleed screw and then release the lever to draw back the fluid from the plastic tube, I go back to same old spongy lever. Please don't even think about suggesting I go and buy a vacuum bleeder, because I have been to every auto shop in my hemisphere and there is not one anywhere.
What am I doing wrong? I am about ready to push my bike into the back yard and burn it !!!!
HELP !!!!!! It almost seems that the master cylinder is not drawing in any fluid to replace the lost fluid at the bottom, and yes the reservoir is full.
Thanks for the help.

  • e.myers

Posted 05 February 2004 - 03:41 PM

#2

Never had to bleed brakes on my bike but I've done it many times on my cars.
I've always had someone do it with me so I've never used the tube in the can trick.
I'd just leave the reservoir cap off, have my partner apply full pressure to the brake then I'd break the bleed screw loose while my partner continued to apply pressure to the "lever" until it bottomed and HOLD IT THERE.
Then I'd crank the bleed screw back in and instruct him to let off the lever completely then apply pressure again. I never would have them pump the brakes at this point because (if I'm remembering correctly) it kinda aggravates the system by distributing whatever air is already in there (you are bleeding remember)throught the system.
So, only have them put pressure on the lever again holding the pressure. You then break the bleed screw again and they follow through with pressure until the break bottoms again holding it there until you tighten up the bleed screw. Repeat until no more air bubbles come out of the bleed screw.
Also, you want to check everytime after you break the bleed screw to make certain the reservoir is full.
I don't see any reason why this shouldn't work on a bike. Only prob is it takes two people to do it.
Anyone see any flaws in what I'm describing?
On second thought, maybe I have pumped the brakes up before breaking the screw loose. Not trying to confuse matters but maybe it's worth a try not pumping it up.
Other question would be is why were you bleeding them in the first place? Were they spongy already?
Hope this helps.
Eddie

  • Secks

Posted 05 February 2004 - 03:44 PM

#3

I appreciate the advice, but the problem is that when I pull the lever the next time, there is absolutely no pressure. So loosening the bleeder screw again does zero.

  • e.myers

Posted 05 February 2004 - 03:50 PM

#4

Humh.
Believe me, I'm not giving out ADVICE. Just caught you first so thought maybe I could help. Anyway, So if you were to do as I've described and "pretend" that you were feeling resistance with the second pull, when you break the bleeder loose you would not get any air out? I would think that it would be possible to have so much air in there that you have to purge the pure air before you can get any noticable resistance.... maybe needing to pump them up initially to get some resistance and then start with what I'm describing.
I'm gonna go back and read your original post again.
Eddie

  • Secks

Posted 05 February 2004 - 04:01 PM

#5

When I start I have a mushy lever. I squeeze it hard and at the same time loosen the bleeder screw. A little fluid comes out as the lever gets closer to the bars. I close the screw(without releasing the lever) and then release the lever. When I pull it again, there is nothing there and no amount of pumping will give me any pressure at all.If I pull on the lever now and release the bleed screw, nothing comes out. No air, no fluid. Could my master cyl. be hooped?

  • SUnruh

Posted 05 February 2004 - 04:12 PM

#6

almost sounds like you need a new set of cups in your master cylinder. ie rebuild the master cylinder.

or you have a humdinger of a bubble in it.

take the caliper off the fork. hold the caliper ABOVE the handle bars. then bleed it.
air rises. if you have a bubble, it will come out this way.

  • ryan_yz250f

Posted 05 February 2004 - 04:13 PM

#7

The seals may have gone on the master cylinder. It happened to my old bike but my old is a 1994 KDX 200. I Replaced the seals and it is like brand new. I made me mad too. I was ready to shoot mine also because when i was riding at about 30 mph the brakes locked up before i fixed them.

  • e.myers

Posted 05 February 2004 - 04:55 PM

#8

Secks-
That's why I was wondering if you were experiencing a PROBLEM before you decided to bleed or you were just changing your fluid.

  • sjwr450

Posted 05 February 2004 - 05:04 PM

#9

Did you change anything? Brake line. Takes around a thousand pumps to even begin to get pressure. I know I have changed 2 of them.

  • DArcy_Davidson

Posted 05 February 2004 - 05:55 PM

#10

Check out this conversation for some ideas.

http://www.thumperta...true#Post709342

  • Secks

Posted 05 February 2004 - 06:48 PM

#11

O.K. now I am confused. A buddy showed up with a large syringe . I filled the syringe and a foot of clear hose w/ fluid, opened the bleeder and tried to push fluid back up the line. It was like the bleeder was closed. nothing went in. I took the bleeder off and checked that it was clear and tried again.. Nothing. Is my bike possesed?

  • tranqwhl

Posted 05 February 2004 - 07:07 PM

#12

you did take the cover off the master cylinder, right?

  • Secks

Posted 05 February 2004 - 07:20 PM

#13

Yes cover off. Now this is getting to be a humorous situation. The diaphram under the cap seems about 3 sizes too big. It will not go back in. AAAARRRGGGGGH !!!!!

  • Jurgen

Posted 05 February 2004 - 10:07 PM

#14

I had a simular problem. Used a entire bottle of brake fluid without results. I could not get a firm response no matter what. I bled my brakes many times without problems.

Talked to a guy at my local track and he made me aware of the little ajuster screw on the brake levler itself. I have never noticed that little thing. Ajusted it out a little, and now I got the best brakes I ever had :)

I may be a nOOb and saying something that is very ovious, but if you have not tried it, its worth a shot.

  • e.myers

Posted 06 February 2004 - 02:24 AM

#15

This is a REEEAAAAALLLL long shot but I actually did it one time. I put powersteering fluid in my CAR master cylinder. Reached in the trunk and grabbed the bottle (same type for Brake and Power steering fluid) and dumped it in. Guess what. It causes rubber (seals and diphragmns) to go to hell. THEY SWELL. Now that I've dropped my drawers I'll be on my way. :) :D

  • RCannon

Posted 06 February 2004 - 04:02 AM

#16

Try holding the lever in the depressed position overnight. Wrap a bungee around the grip and lever.

I usually always end up with a better feeling brake afterwards.

  • tctrailrider

Posted 06 February 2004 - 07:06 AM

#17

Are you using Dot4 fluid? Different grades compress differently.

  • cypressd

Posted 06 February 2004 - 07:16 AM

#18

I had the same problems once on a yz125. To initially get all the air out and get some resistance on the lever, I cracked the banjo bolts when I was bleeding instead of the bleeder screw. Then, when I felt some resistance, I switched to the bleeder screw. You do it the same way, just letting the pressure out at the banjos at the caliper or at the master cyclinder on the bars. Worked like a charm. Hope this helps.

  • MN_Kevin

Posted 06 February 2004 - 07:28 AM

#19

Been there, done that.

First off, you need to bleed the master cylinder. Try pumping the brake, holding the lever in. Loosen and tighten the banjo bolt at the TOP of the brake line. You may need to do this several times. It still may not work.

I have gone back and forth, first trying at the master cylinder, then the caliper and back again.

I had a heluva time when I swapped to a stainless steel line on my WR420. I was there FOREVER trying to do this. Out of exasperation, I did the press the fluid in from the bottom approach. I used a turkey baster w/ clear, flexible plastic tubing attached (thoroughly cleaned and flushed W/BRAKE FLUID) to slowly push the fluid up from the bottom at the caliper. This DID work. I still bled from both ends however for the icing on the cake.

Now, UNLESS you went Honda routing, you CANNOT have that stupid Yamaha loop-de-loop at the caliper while futilely attempting to do this. Hell WILL freeze over before you EVER get that bled.

As mentioned, you can hang up the brake rig from the ceiling to let the air float up.

I have done all of this, which DID lead to success.

  • Secks

Posted 06 February 2004 - 07:47 AM

#20

Thanks to all that offered up some advice. I ended up removing the line from the master cyl. and pumping the lever a few times. Not even a drop came out of the full reservoir. I blew into the now removed brake line and only a few drops came out the bottom. It would seem that the entire brake system below the master was empty. I can not explain this as the problem that led to this (repair) was a soft brake lever. The brakes worked, but not great.
I will rebuild the master and try the reverse fill with a syringe tomorrow. If that doesn't work, maybe there is a 1982 Honda xr250 with a mechanical drum brake in my future.Check the 'bikes for sale' section for the results.
Thanks for the help.
:)




 
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