Gy6 front brake will not pressurize By drew (Read 729 times)

[drew]

Hello all. I have a 2012 Baccio gy6 50cc. Since i bought the bike about a year and a half ago, the front brake was giving me problems then it finally stopped working. I figured it was a froze caliper because i was getting no pressure. Changed caliper and bled the thing, nothing. Changed the master cylinder, still nothing. Changed the brake line!! Still nothing. The rotor is not bent. I have been thru two master cylinders because i thought they were defective. I would install the master cylinder and it would work with pressure for about 2 weeks then have no pressure. I also replaced caliper twice and brake line because i thought i contaminated the last set and it still will not pressure. I bought a hand gun bleeder from autoparts store and still no luck. Am i not bleeding it enough? The master cylinder just squirts liquid up and no bubbles. Is the master cylinder defective!?!
It really sucks riding around with just the back drum brake lol.
Thanks!

[drew]

If it counts I am ordering these parts off of ebay.

[trashtruck12172]

sounds like a bad master cylinder if it was working for 2 weeks then stopped.

[drew]

Thats what I thought and I replace the master cyl. again and the same thing happened. Worked for about 2 weeks then slowly lost pressure. It is weird, sometimes it will build pressure while im driving the scoot but will only build enough pressure to actually brake for about 1 or 2 seconds then loses pressure immediately. I am completely stumped. Should I order the master cylinder from a reputable shop? Is it the ebay master cylinders just breaking after 2 weeks or so? Lol
Thanks

[cyborg]

Bad master cylinder on all counts,,,I've had brake and hydraulic clutch masters be bad right out of the box,,,get a good one from a reputable dealer

[drew]

Thanks cyborg,
I was thinking the same thing and this has been very frustrating. I also noticed there is a light crack in the caliper from my stupid friend way over tightening the bleeder nipple. Should I replace the caliper to stay away from future probs? Nothing is leaking thru the crack it is very small.
Thanks

[drew]

Anyone know a good website to buy this master cylinder off of? The "reputable" dealer over here in Naples, Fl is about double the retail price lol.

[richardv]

The crack in the wheel cylinder may not leak fluid but it could still leak air into the fluid. That is not good.

[jct842]

If you have a crack in it I would replace it.

[drew]

Yes i will also replace the caliper.

[drew]

Is there a certain brand master cylinder I should get?

[Alleyoop]

They are all made in china so do not worry about the brand JUST make sure the cylinder kit matchs what is on your scoot. IMO the problem is there is air in the line someplace and is why you are not getting any pressure.
Here is how to fill it up and bleed them at the same time.
The cylinder is working just fine since you said it squirts up when you squeeze the brakes trying to get pressure.
Alleyoop

[drew]

I followed the procedure in the video. I sent fluid thru about 10 times. I am slowly gaining pressure back but is still releasing pressure and it still doesnt seem right. Do i need to bleed more? I dont see any air bubbles coming thru master cylinder.
Thanks!

[Alleyoop]

Have you change the BRAKE PADS the pads might be worn down?

[drew]

The pads are brand new as well as the caliper is, Alleyoop.
Thanks!