[ISuckAtThis]

Just got aftermarket clutch and brake levers with master cylinder. Put it all together to find brakes are not working in the slightest. No pressure, lever pulls all the way to handle. Sat there for 10 minutes trying to build pressure pulling and releasing but nothing. Bleed the lines alittle to make sure it was flowing, topped fluid back off. I'm not sure what the issue is. Yes it's the correct brake fluid.

 

[ISuckAtThis]

Photo of what they are if that helps. Bikes a 2018 honda grom

 

[cmonSTART]

Master cylinders are notoriously hard to bleed properly. Even getting fluid down to the caliper there can still be air in there. You can try a couple things.

A. You can clamp or tie the brake lever closed (against the handlebar as if applying brake) overnight with the handlebars turned to the left (so air will hopefully flow uphill and out.) Release it in the morning and try to bleed the brakes again. It's simple but it often works.

B. Remove the master cylinder and try to bleed it on the bench. You'll have to bleed the brakes again when you reattach it, and you'll have to be careful not to drip brake fluid all over your bike when you reattach it. Brake fluid ruins paint.

That's the easy stuff I can think of. There's a slim chance the master might be defective (if it's an ebay cheapy) but there are other things to check first before jumping into that.

 

[ISuckAtThis]

Master cylinders are notoriously hard to bleed properly. Even getting fluid down to the caliper there can still be air in there. You can try a couple things.

A. You can clamp or tie the brake lever closed (against the handlebar as if applying brake) overnight with the handlebars turned to the left (so air will hopefully flow uphill and out.) Release it in the morning and try to bleed the brakes again. It's simple but it often works.

B. Remove the master cylinder and try to bleed it on the bench. You'll have to bleed the brakes again when you reattach it, and you'll have to be careful not to drip brake fluid all over your bike when you reattach it. Brake fluid ruins paint.

That's the easy stuff I can think of. There's a slim chance the master might be defective (if it's an ebay cheapy) but there are other things to check first before jumping into that.

Alright, I got a rubber band holding down the break lever now and will try again tomorrow after work. Hopefully this works. They were 70$ roughly idk if that's cheap or not but let's hope that's not it.

Maybe I didn't bleed properly either. Video or tips?

 

[RonK]

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Some bikes have the problem with air in the lines stuck in the area where it splits to go to each side in the front. To get the air trapped there out, you may want to try leaning the bike to the side and tap on the tee to get the air bubble into the lower line where it can be flushed out of the bleed valve. I do like self bleeder valves such as these:

https://www.amazon.com/Russell-639570-Speed-Bleeder/dp/B000CPCOB6

Note these may not be the exact ones for your bike, but just an example of what I mean. You can search on Google. This type of bleeder makes the process much easier when flushing.

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[joewasaki73]

i kinda got the impression that maybe you didn't understand how the bleeding procedure works.
simplest thing would be to watch a couple of youtube videos.
avoid the guys with a cigarette and a camera in one hand and a crescent wrench in the other.

 

[cc rider]

If its a bleeding issue, get a mity vac or something similar. It will save you LOTS of time. For regular bleeding , you dont need it as much but, they are great for when you have to start from scratch with the bleeding process.

 

[DPicketts]

I put a similar brake lever on my bike and I had to file down the part of the lever that pushed on the master cylinder piston because it would not let the piston out far enough to clear the little hole that lets air out. Before you do anything drastic, to check that this is the problem you can take out the bolt holding the lever on and replace it with something thinner like a screwdriver and try bleeding the brakes.