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Post by lain on Aug 11, 2016 15:55:26 GMT -5
I do this so rarely and just did it to my 150cc rear brake, and now can't get pressure. I believe I did it in the wrong order, and I look up posts and videos but keep getting mixed instructions. Some say to compress the brake lever, open the bleeder, close it, then let go of the lever and repeat, others say to open the bleeder,squeeze(compress) the brake lever, THEN close the bleeder, let go of the lever and repeat... I tried both to no avail, so maybe neither is right..?
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Post by mftic on Aug 11, 2016 16:57:37 GMT -5
Pump up the lever and hold. Open bleeder while lever moves to bar. As soon as lever stops moving (resting on bar) close bleeder and repeat. Make sure you pump up the lever though. Squeeze 4-5 times first then hold.
This is not the best way to do it but you probably know this. I now use a brake bleeder and love it.
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Post by lain on Aug 11, 2016 18:10:16 GMT -5
Ugh, I've been trying to do this for the past 5 hours straight, I'm sure the system is full and no air, the air bubbles stopped forever ago... I've tried every which way and ensured there is no leaks and it just WON'T PRESSURIZE.... I've wasted 76 ounces of brake fluid in total already!!! It's looks just as good coming out as going in, no air bubbles, still 0 pressure and no stopping power at all...
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Post by rcq92130 on Aug 11, 2016 18:19:21 GMT -5
If you changed the brake pads, or for some other reason pushed the current pads (and thus the piston) back into the cylinder) just keep pumping the brakes. As soon as the piston is pushed far enough out to contact the disk (and thus move no farther), braking will resume. Just keep an eye on the level in the master cylinder.
Air in the system will generally NOT lead to a loss of all braking pressure - just a "spongy" feeling.
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Post by lain on Aug 11, 2016 18:22:06 GMT -5
I pushed the pistons into the caliper to make sure they could move, required a clamp, they had a lot of resistance at the caliper, but no resistance in the lever but pumping it made the pistons go back out... but still no resistance...
It was actually working fine before, I only decided to change the fluid because it looked black.
All I have done so far is try various methods of bleeding because I can't find any consistent method. Each of them had the same results, no pressure at the lever but pressure at the caliper. Pulling the lever does not even slow the bike down, luckily I delayed doing the front brake line so I was not crashing into things... Ugh it's so hot today and I'm so frustrated with this not pressurizing.
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Post by mftic on Aug 11, 2016 18:31:03 GMT -5
I've had that happen once before. I just kept pumping the lever till I had some feedback. Must have pumped it like 20 times before some pressure built up and I could open the bleeder.
You really shouldn't have had any failures doing it this way. Not sure what the problem is.
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Post by lain on Aug 11, 2016 18:47:09 GMT -5
I tried pumping it multiple times and then loosening the bleeder, it would gush out in a huge fast burst then stop bleeding within a couple seconds. Then I would tighten the bleeder and pump it again, holding the lever each time i opened the bleeder.
Also tried the other method where you pump it 4-5 times then let go of the lever and squeeze it in and while it was going in unscrew the bleeder and when it made contact with the handlebar screwed it back in.
There is no leaks... This is driving me insane, I need to get to a meeting in the morning on this thing and need both brakes, just the front isnt enough when carrying a passenger like I'll be doing.
I've used up soooo many bottles of brake fluid it's ridiculous. I really haven't the slightest clue why it isn;t working, it worked fine and was almost rock hard pressure before even though before I changed the fluid there was almost nothing in the reservoir.
Could the master cylinder be broken? Could it be possible for them to brake simply from bleeding out old fluids?
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Post by crawford on Aug 11, 2016 20:39:31 GMT -5
Remember the stroke you move is very little it takes a long time till all air is gone. I use a reverse bleeder everyone know air wants to go up much easier not fighting the way air moves.
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Post by lain on Aug 11, 2016 21:38:48 GMT -5
Remember the stroke you move is very little it takes a long time till all air is gone. I use a reverse bleeder everyone know air wants to go up much easier not fighting the way air moves. What reverse bleeder do you use on scoots? I'd rather buy one I know people have used successfully. Spent another couple hours trying to bleed the system, another 32 ounces of brake fluid the world will never use : ( got a SLIGHT bit of resistance in the lever after removing the hose from both ends and checking for air, still didn't get any air out the hose on the bleeder but got a slight resistance so idk, i did everything else as I was doing it before except for loosening, compressing the lever and tightening the hose and letting go of the lever. While continuing to do this did not help make more pressure, it did give it a little pressure although stil not enough to hold the wheel still for even hand turning. I just don't understand how this is soooooooo easy on my other scooters, but on this I spent an entire day trying to just get SOME stopping power.... but with my other scoots I can do it the same ways and be done in half an hour every time... Another reason I'm frustrated is I spilled a bunch of brake fluid cuz I got impatient... my paint job was like new, now it looks like a salvage project by the paint job : ( |
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Post by hillbillybob on Aug 12, 2016 6:10:12 GMT -5
I installed speed bleeders on my scoot almost 3 years ago..... infact, put them on my bigger bikes at the same time. They work great, and make a fluid change, brake or hydraulic clutch, a walk in the park. This link will give a little more info.... speed bleedersAccording to my records, my scoot took the m8x1.25 size.....would think most Chinese scoots would be the same.....but as they say.....your actual mileage may vary. |
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Post by mftic on Aug 12, 2016 7:50:59 GMT -5
I got something like this pump. That way I could check for air leaks also in the vacuum system. It's pretty much what you are doing with the brake lever but way more effective. Prefer this method to reverse bleeding. Problem with reverse bleeding is you are pushing all the contaminated fluid back up into the master cyclinder. I've actually ruined one once but admittedly that was on a car. Everything was super old and nasty anyway. *it's not fun when you have a problem like this. I actually think you almost got it though. Just need to pump that brake lever more and faster to build up pressure then bleed it. My disclaimer is I've never gone through more than one bottle though so.... |
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Post by crawford on Aug 12, 2016 9:08:00 GMT -5
Phoenix Systems 2104-B V-5 Reverse Brake and Clutch Bleeder This is the system I use works great and your not banging your head against the wall LOL
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Post by crawford on Aug 12, 2016 9:09:38 GMT -5
The other system isn't for reverse bleed I have that also just not that company.
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Post by lain on Aug 12, 2016 12:02:11 GMT -5
Well I heard about tying your brake handle overnight, tried that now I have enough pressure to stop suddenly with 2 ppl riding if I pump it 3 times fast, so I guess you guys are right, almost there but apparently not completely. Will try bleeding it again if it doesn't continue to get better over the next couple days or so, but I have enough stopping power now but the lever is just really not giving much resistance still even when pumping, but it makes the brake work.
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Post by JerryScript on Aug 12, 2016 14:48:30 GMT -5
You should get a second person to pump the brake lever, and closely inspect the entire brake line. You may have a balloon appearing/disappearing in the brake line itself. Some swear by metal woven brake lines for just this reason.
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