Kawasaki Ninja 300 Forums banner
1 - 11 of 11 Posts

· Registered
Joined
·
5 Posts
Discussion Starter · #1 · (Edited)
hoping someone can help me out here, can’t figure out why my rear brakes won’t bleed (not functioning at all) . I tried pumping out for like 10 minutes and a drop barely came out the valve. Can’t find anything online as to how to possibly unclog it but I feel that’s the case as I was able to do flush out the front brake no problem. Can’t figure out how to start my own thread on here, but just found this website today. Any help would be soliddd. Thank you all! edit found the post button smh
 

· Registered
Joined
·
5 Posts
Discussion Starter · #2 ·
hoping someone can help me out here, can’t figure out why my rear brakes won’t bleed (not functioning at all) . I tried pumping out for like 10 minutes and a drop barely came out the valve. Can’t find anything online as to how to possibly unclog it but I feel that’s the case as I was able to do flush out the front brake no problem. just found this website today, Any help would be soliddd. Thank you all!
 

· Registered
Joined
·
407 Posts
so you cracked your bleeder screw on rear caliper and pumping the rear brake doesn't force any fluid out the bleeder? You may have a clogged bleeder, have you tried completely removing the bleeder screw to see if that at least lets you push fluid out? (silly question, but are you sure you have brake fluid in your rear reservoir?)
 

· Registered
Joined
·
406 Posts
I had a similar issue when my rear master cylinder died. It wasn't sucking fluid through, the pedal wasn't coming back up, ect. The brake still worked, but it would not bleed at all.

I fixed mine by buying the rear master cylinder piston and rubber parts rebuild kit, the OEM parts. Put it in, and all is perfect again.

I think the rear master cylinders on these bikes are kinda mediocre. I have a friend who's having their rear brake just beginning to stop working all together. Probably master cylinder as well.

It's cheap, just be ready to get your hands a bit dirty, no big deal. You will need snap ring pliers.

-Mike
 

· Registered
Joined
·
5 Posts
Discussion Starter · #6 ·
@iahawk I couldn’t see any fluid in the reservoir so I topped off at the start. That’s when I was getting baffled since the front was perfectly fine bleeding out. This bike HAD sat out for 2 years before I bought and cleaned it up which Is why I’m cleaning all the fluids now. So it very well is probably clogged, but no I did not completely crack the bleeder screw to see if anything would happen. Might try out after work today! But yes it is full I promise lmao
 

· Registered
Joined
·
5 Posts
Discussion Starter · #7 ·
@Mike- thank you for the helpful insight, first bike ever that I’m fixing up before taking it to get my license(previous reply mentions it’s been out in the weather for 2 years) so i gotta have it at 100% and could not find anything about brakes not bleeding online. I’ll look up a video on how to rebuild later and get those parts ordered if cracking the screw all the way doesn’t allow for any drainage. My rear brake has minimal force going now and just springs right back up but nothing happens. I’m assuming it should feel stiff like the front one… thank you guys for the help.! Will come back here with updates later on
 

· Registered
Joined
·
406 Posts
That sounds exactly like what I had. When I said my pedal "wasn't coming up", I actually meant that the pedal itself does come back up, but when I press it again it has no resistance. My master cylinder was essentially 'getting stuck' when I tried to bleed. I am almost certain what you have is what I had. If that is the case, the fix I did will solve your problem.

Brakes almost never just "clog up", especially on a vehicle that is maximum 9 years old. If you have stock brake parts, that is almost impossible for sure.

Make sure also when you fill the reservoir that you don't fill it up past the full line, and also make sure the rubber boot under the cap isn't distended. It happens naturally when the brake pads wear, so when it happens you just need to take the cap off, repack the rubber boot into its natural shape, and reassemble. This happens on every N300 I've ever worked on eventually, as the rear pads wear, it's normal. Just make sure you leave some air in the reservoir when you fill up, it has to be there to make the system work as designed.

The rear brake master cylinder rebuild part is Kawasaki P/N 43020-1057. You will need that kit, the snap ring pliers I mentioned, new brake fluid (you can use DOT 3 or 4 in the rear, but I recommend just using high quality DOT 4 fluid all around) and some brake cleaner, cotton swabs, microfibers, and general tools.

The job is pretty simple. For reference, the job is described in the service manual available online on page 2-45 of the PERIODIC MAINTENANCE section. The job is essentially just draining the brake fluid, removing the master cylinder, taking it apart, cleaning, and installing the new parts, reinstall the master, fill with brake fluid and bleed.

And of course, if you get in there and see anything wrong, you must fix it. Brakes are important. If you don't feel comfortable working with your brakes (which is totally fine, brakes have to be done correctly, it is a safety critical system) take it to a local shop. But if you're handy with tools even a bit, you can do this for the cost of the cylinder piston kit and brake fluid, very cheap stuff.

Hope this helps. If you get stuck, many people here can help you along the process and answer questions.

-Mike
 

· Registered
Joined
·
287 Posts
The brakes on the 300 seem less than mediocre. My 20 year old dirtbike has better Nissan calipers on it.
Actually the brakes are fine, it’s just the quality of the calipers seem reall cheap compared to others.
If the bleeder is not clogged when you check, you can try taking the rear caliper off the swingarm and holding it above or below the master cylinderand pump the brake lever. Sometimes that help get air bubbles moving.
 

· Registered
Joined
·
5 Posts
Discussion Starter · #10 ·
That sounds exactly like what I had. When I said my pedal "wasn't coming up", I actually meant that the pedal itself does come back up, but when I press it again it has no resistance. My master cylinder was essentially 'getting stuck' when I tried to bleed. I am almost certain what you have is what I had. If that is the case, the fix I did will solve your problem.

Brakes almost never just "clog up", especially on a vehicle that is maximum 9 years old. If you have stock brake parts, that is almost impossible for sure.

Make sure also when you fill the reservoir that you don't fill it up past the full line, and also make sure the rubber boot under the cap isn't distended. It happens naturally when the brake pads wear, so when it happens you just need to take the cap off, repack the rubber boot into its natural shape, and reassemble. This happens on every N300 I've ever worked on eventually, as the rear pads wear, it's normal. Just make sure you leave some air in the reservoir when you fill up, it has to be there to make the system work as designed.

The rear brake master cylinder rebuild part is Kawasaki P/N 43020-1057. You will need that kit, the snap ring pliers I mentioned, new brake fluid (you can use DOT 3 or 4 in the rear, but I recommend just using high quality DOT 4 fluid all around) and some brake cleaner, cotton swabs, microfibers, and general tools.

The job is pretty simple. For reference, the job is described in the service manual available online on page 2-45 of the PERIODIC MAINTENANCE section. The job is essentially just draining the brake fluid, removing the master cylinder, taking it apart, cleaning, and installing the new parts, reinstall the master, fill with brake fluid and bleed.

And of course, if you get in there and see anything wrong, you must fix it. Brakes are important. If you don't feel comfortable working with your brakes (which is totally fine, brakes have to be done correctly, it is a safety critical system) take it to a local shop. But if you're handy with tools even a bit, you can do this for the cost of the cylinder piston kit and brake fluid, very cheap stuff.

Hope this helps. If you get stuck, many people here can help you along the process and answer questions.

-Mike
mike you are a gift from above.P/n and manual reference you are the man! I’m pretty comfortable with working on the bike despite being new to it all, try to watch plenty of videos to get a good understanding of all the parts I’m working on. ordered a physical owner manual so I don’t have to keep jumping back to a pdf so that should help out following directions. I have a bottle of dot4 I used for the front brake, may take some out as I might havenot left a gap of air for the front to work. But I’m gonna order that rebuild kit and pliers off revzilla today and get started soon. Thank You a ton for all the information! More than I could have thought to ask for. Last question: the rubber boot you refer to is for the rear master cylinder correct? My front one has a black top that is sort of like a glacier as to where the top is flat but beneath it goes into the brake fluid and has shape. The rear on theother hand has a twist cap with a plastic … top? That goes beneath the twist cap , assuming to stop any possible leakage from the twist cap being twisted on unaligned with the thread.Under the clear cap is a black plastic piece that has a little tunnel feeding into the brake line .
 

· Registered
Joined
·
406 Posts
I apologize, I may have mixed up the words!

The rubber boot I mentioned in the 3rd paragraph is P/N 43028-1065, and it goes in the fluid reservoir, not the master cylinder. You are correct, there is also a plastic piece that goes between this boot and the screw on cap. I think that plastic piece just helps keep things sealed.

The part I mentioned you would need to purchase is a master cylinder 'piston and seal' kit. It has the metal brake piston, and the rubber seals to seal off the piston inside the master cylinder. That should be all you need to replace!

Hope this helps. You sound plenty equipped to dig into the bike, I'm sure it will make more sense once you open it up yourself and see how it all works. Just keep all the parts clean, and assembled them lubed with brake fluid in the master cylinder, and you'll be set!

Good on you also for buying the paper manual. Never a bad idea!

-Mike
 
1 - 11 of 11 Posts
Top