REAR BRAKE HELP PLEASE!!!!! ASAP!!!!!!

[cadarst]

We were fixing to get ready to ride today and my rear brakes started gettin spongy. I took the rear plate of the master and added fluid. We started to bleed the brakes and have now completely lost pressure. We have tried everything we know to do. I took the hose off at the top of the master and there is pressure there, a little bit of fluid comes out when we are bleeding them but the pressure still won't build. Please help any way possible! Fluid is coming out at the bleed screw, but can not build pressure, PLEASE!!!

[BK14MX]

keep bleding it, I have found Honda brakes are a little stubborn to get all the air out. I just rebuilt the rear caliper, and Im waiting for the parts to rebuild the master cylinder jsut to be 100% sure.

[skip #7]

Honda's are difficult to bleed,I use a power bleeder my self,the 02 CRF is notorious for the rear cylinder kit going south my 02 has had two kits ,if this is your problem it's a 35 buck fix,I didn't notice the year of your scoot on your post.

[RCannon]

Sometimes a person can speed this process up by pushing the caliper in on the pins. Pump up the brake lever, then repeat.

[CRF450Racer]

Make sure the bolts holding the brake line are really snug.

I had to replace the brake line as my brakes were spongy and a new master cylinder and Braking Caliper did not fix the problem. The line must have had a weak spot that kept expanding as I pushed on the petal.

[Honda1]

you have a big fat bubble trapped in your brake line. remember bubbles like to travel up. So drop your caliper to the ground, pull the top off the MC, and open the bleed screw. take a medical syringe and fill it with fluid and attached a hose that will fit tightly on to the bleed screw and the syringe.Now turn the syringe facing down and push fluid out the hose keeping the hose higher than the syringe but lower than the caliper pushing fluid until bubbles and air are gone. then attach to caliber and push fluid until MC fills tapping the brake line at the swing arm pivot. Remember, bubbles travel up and its easier to push bubbles than to pull them. do this a few times saving the fluid until you get the hang of it. keep the syringe pointing down lower than the caliper and the caliber lower than the MC. you will notice that the bubbles in the syringe will stay in the syringe and not get in the hose. use a clear hose and keep tapping the brake line while pushing the fluid. Oh I forgot to mention the most important part**** before you start make sure the piston is pushed completely into the caliper thus less area to bleed. use Motel 600 back there. ? i take donations

[scuba821]

try opening the bleeder and let it gravity feed itself.

[cadarst]

Thanks for all input guys, this is what I did! I took it to the Honda shop, and he hooked it up to a hi pressure vaccum to bleed the brakes, they still are pretty spongy, but work off and on. What do you suggest my next step to be, again thanks for all your help! ?

[Jeremyb]

I would bet $100 bucks that it is the brake hose. I just did mine yesterday! A buddy had the same problem and told me to try that first (because he tried it last! LOL). I put on a Galfer from Rockymountainmc.com for $48.

[LawDog101]

Here is the cheap and easy way out of this mess. First, go get a large syringe (less needle) and connect it to the bleed on the caliper. Hook everything up properly on the MC and leave the cap off. Pour fluid into the MC and start pulling fluid through with the syringe. You will notice some bubbles, etc. and then it will start to come out clear. Close off the bleed valve and bleed it a bit and you are done.

Note: A problem that I have not seen on here is this. The honda brake line is rubber and has a coating that keeps it from expanding like a balloon. Over time this breaks down and will allow the line to expand and feel spongy. I got a steel line and it fixed the problem. Also, I filled it back up with Motul 600c fluid. Good Stuff.

James

[BillRoy]

Here is a question; hopefully not a dumb one. When you fill the MC with fluid after bleeding how do you prevent air from getting trapped between the rubber seal and the fluid below it??

Also, after you put the rubber seal in do you pour fluid into the seal itelf before putting the lid back on??

Thanks, I too am having the same (spongy) problem with my 02 rear brake.

[03thumper]

when i justy changed my first set of rear pads i had the same problem...i bled that sob unitl my hand was bledding and it finnaly worked the air out. i was ready to call my buds andf tell them i couldnt go ride that night and all of a sudden bam i had pedal! keep bleeding!

[str8away]

Here is a question; hopefully not a dumb one. When you fill the MC with fluid after bleeding how do you prevent air from getting trapped between the rubber seal and the fluid below it?

just fill the m/c up enough so when u put the cap back on it forces a little brake fluid out over the sides and that'll squeeze out the air.

[MORETORQUE]

Here was my solution to my rear brake problem on my 03 CRF. Pitch the whole entire brake system in the garbage, that rear brake setup is trash plain and simple one headache after another.

I put a RM master cylinder along with the old style Honda caliper and carrier on. Did some slight welding to the swing arm and presto real brakes. THAT REAR BRAKE SUCKS BAD!!!!!!!!!!!!! The old system is a little heavier but the pads last way longer and you can put water in it and it will still stop and never give you a problem.

I have had nothing but problems with the newer rear brake. You will fix it and then down the road the whole thing takes a hike again.

[scotd]

this syringe method works well, I used a two dollar one from a med supply and a 1/4 hose. strappep the syringe to my fork leg full of fluild and used a second one to take out most of the fluid from master cyclinder so as i pumped more in no overflow. zero bubbles that i cound not achieve with my 52. dollar mighty vac.. I am going to do the new line next, think that will help as well.

[TexasBill]

Just buy a good used master cylinder on EBAY...my 02 did same thing, it would intermittently be spongy...you can find a good and newer year master cylinder on EBAY for the cost of rebuild kit.