Honda CX 500 Forum banner

Rear brake not bleeding

2K views 14 replies 8 participants last post by  Sidecar Bob 
#1 ·
So last weekend I started a rebuild of the rear brake caliper. Was supposed to be quick rebuild but once I got it apart I found I needed new pistons I didn't have. So I packed things up and I tightly wrapped the end of the brake line in some paper towels so it wouldn't drip on anything. I then went and ordered the missing pistons.

So fast forward to this weekend, I got in the parts Friday and I reassembled the calipers without any trouble and installed them. Then started to try and bleed the system. This is where the issue came up. No matter how much I pumped I didn't seem to be getting any fluid out the bleed hole. I pulled the valve and made sure it was clear.

Last check I did was to take the bleed line loose and tried pumping the brake. I got nothing, line is bone dry.

So does anyone have any ideas? I had rebuild the master cylinder a few years ago. So don't feel like that should be an issue. There some priming I need to do to the system?
 
#4 ·
OK, if you loosen the brake line at the mc, will any fluid come out?

So, if the brake line is not tight enough on both ends, air can bleed back in and cause your symptoms.
 
#8 ·
Yeah, I think I will go and get one. I was using a "one man brake bleeder" that is basically just a hose going to a small catch bottle. Something that actually puts a vacuum on and helps pull it would be great.

It is the rear brake, the turbos came with a single disk in the rear. Although going back to getting a brake bleeder, my front brake reservoir does look like it needs replacing as it is cracking. I'm surprised it isn't leaking yet. So buying a bleeder will likely be well worth it. I probably should go ahead and replace the brake lines while I am at it......

Thats about how it works though, wanted to get it fixed up real quick and get back on the road. Seems instead I need to just slow down and really spend some quality time and $$ on this bike. Especially don't care to jump on if I can't have 100% confidence in the brakes.
 
#6 ·
First off, I have to assume you mean front, at least I never heard of rear disk let alone a dual setup. If so they should gravity bleed to a point that would have soaked through paper towels and leaked all over anyway.
I'd have to guess the master, lines or the junction box is blocked.
 
#9 ·
If you still have rubber brake lines you probably should. If they are the originals they are almost a quarter century past their best before date...

BTW: The Eurosports came with the same rear brake as the Turbos so that makes 4 models in the range with rear discs...
 
#10 ·
:eek: I got confused with the plurals and non plurals. Caliper, calipers, pistons. Sorry, I'll shut up now. :confused:
 
#13 ·
I just got in my parts so hopefully this weekend I will get this all fixed if not sooner. One thing that has me bit worried at the moment though is this set of brake lines I got from JDA. I ordered both front and rear lines from them to just fix it and fix it right. The lines look mighty short to me though. Like the rear brake line is only about a foot long. I assume they know what they are doing though, so hopefully this will work and not cost me another few weeks of waiting on parts.
 
#14 · (Edited)
One thing I do after a rebuild is to pre-bleed it. While it is my shop I put it in a vise and put my finger over the output and purge all the air out of the master cylinder when I get it to where it is putting out just fluid put the plastic plugs(these came with the new master you may have to get them at the parts store) back in the master and install it.Next fill your slave with fluid then hook up the line to it with one or two threads and put a rag around it but fix the rag so you can see the connection,next fill the line and let it leak out at the slave end until the line is full and now tighten the slave line and attach the master to the line. I also use speed bleeders they speed this up greatly you just have to get the right size.Now follow the instructions on the speed bleeder.Here is an example(Dorman M8 x 1.25 x length 28mm) maybe not your size but for my GL500I front calipers.Dorman 12705 Rear Bleeder Screw. more information here.http://r.search.yahoo.com/_ylt=A0LE...der.com//RK=1/RS=A9rOmF5f4KPWk7jze_IKGRYe_e4- . short U-Tube video.http://r.search.yahoo.com/_ylt=A0LEViNZLXpZGbYAaKYPxQt.;_ylu=X3oDMTByOHZyb21tBGNvbG8DYmYxBHBvcwMxBHZ0aWQDBHNlYwNzcg--/RV=2/RE=1501208025/RO=10/RU=http%3a%2f%2fspeedbleeder.com%2f/RK=1/RS=A9rOmF5f4KPWk7jze_IKGRYe_e4-
 
#15 ·
If you fill each part individually you will still have bubbles at each connection, particularly where the brake line meets the master cylinder which will necessitate pumping all of the fluid that you put into the brake line and the caliper out while pumping the bubbles through. A vacuum pump is still the best way but if you don't have one this is the way to do it.

BTW: Tom is a member of ngwclub.com (Naked GoldWings forum)
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top