Help with Chinese brakes

[Frankencelery]

My son's little 90cc Chinese quad suddenly has no brakes. The fluid was down but I added some more, then attempted to bleed them. Seemed to go ok, but there's still nothing. It doesn't feel there's anything there when you pull the brake handle. I can't figure out whether I've still got an air bubble or the master cylinder is bad. Anyone have any experience with these?

[Frankencelery]

Update: (or not)

I read a bunch of posts about 200x front brakes being very difficult and having to pull the air out through the bleeder screw using a vacuum pump. I don't have a vacuum pump, so in the best redneck tradition, I used my mouth! My brake bleeder canister has a hookup for a pump and I just used that, but unlike the first time, the bubbles just kept coming. I even put teflon tape around the bleeder screw threads to make sure I wasn't pulling air in through the outside, but I just couldn't get it done. I guess I need to buy or borrow one of those mightyvacs. Or maybe there really is a leak in the system somewhere.

[just ben]

my daughter had one that the bleeder was one the bottom of the caliper and it was nearly impossible to get all the air out. If that is the case with yours try unbolting the caliper and spin the caliper around the rotor so that is on the front of the rotor and the bleeder points up, Bleed out the system until the brakes are nice and firm and then remount the caliper.

[jb2wheels]

How did the fluid get low in the first place?

[Frankencelery]

How did the fluid get low in the first place?

Oh, you had to ask. I was hoping to avoid that one! Actually, after sitting for a long time, the brake wouldn't work at all. The sight glass was always completely full, so you couldn't see the edge of the fluid anyway. I took the cover off and poured into what I thought was the reservoir. It took a little tiny bit. Then I realized that was just the rubber insert that sits inside the reservoir. By that time I couldn't tell if it had ever really been low or not.

Oh and just ben, the bleeder is on top of the caliper.

Please forgive my disc brake ignorance. All my trikes have drum brakes!

[El Camexican]

Don't take this the wrong way, but you are closing the bleeder beween pumps, right? Sorry, I have to ask as you say you are a drum guy. If proper bleeding won’t do it I’m guessing a seal is leaking. Keep in mind that your ATV likely cost about $250 US FOB China, so its not like they come with Brembos. If all else fails you may want to try getting an English edition of Confucius Big Book of Chinese Brakes & Other Stopping Stuff.

[Frankencelery]

El Camexican, your obvious love for Chinese quality and engineering comes through loud and clear!

I suppose I deserved that, especially after I tried to pour fluid on top of the rubber insert. Yes, I was closing the bleeder screw between pumps. I've bled lots of car brakes, but never an ATV, so I didn't know if there was some fundamental difference between them besides being smaller.

[Scootertrash]

The problem I have come across working on these Chinese wheelers/atvs/motorbikes, is that the companies usually aren't around for long and parts are hard to come by. You can google "Chinese atv parts" and find some suppliers, but the ones I've tried don't even have a parts breakdown , or you never get a reply to an email. good luck!! Or should I say Good Ruck!!!

[just ben]

Oh, you had to ask. I was hoping to avoid that one! Actually, after sitting for a long time, the brake wouldn't work at all. The sight glass was always completely full, so you couldn't see the edge of the fluid anyway. I took the cover off and poured into what I thought was the reservoir. It took a little tiny bit. Then I realized that was just the rubber insert that sits inside the reservoir. By that time I couldn't tell if it had ever really been low or not.

Oh and just ben, the bleeder is on top of the caliper.

Please forgive my disc brake ignorance. All my trikes have drum brakes!

I am a bit confused. After adding to the top of the diaphram and realizing ypur mistake, Why didn't you just pull it out to see where the fluid level really was? If you ran the master down to the point of being dry you will probably need to "bench bleed" the master

[Frankencelery]

I am a bit confused. After adding to the top of the diaphram and realizing ypur mistake, Why didn't you just pull it out to see where the fluid level really was? If you ran the master down to the point of being dry you will probably need to "bench bleed" the master

I didn't look carefully. It seemed low, so I added more, but there was fluid in the reservoir.

[Furno]

Try tapping on the brake line while someone pulls the handle, itll work out bubbles if thats the case.

[El Camexican]

El Camexican, your obvious love for Chinese quality and engineering comes through loud and clear!

I suppose I deserved that, especially after I tried to pour fluid on top of the rubber insert. Yes, I was closing the bleeder screw between pumps. I've bled lots of car brakes, but never an ATV, so I didn't know if there was some fundamental difference between them besides being smaller.

LOL. I do Q.C. work over there, so yea, I have a special spot in my heart for their attention to detail. Just wait ten more years, they'll be competing with the Japs, but we won't be able to afford the products.

Best of luck with that thing.