Rear Brake Bleeding Question

I have a 1999 VFR800, and I just did a full brake job on my bike that has 19k miles on it, and it has obviously never had the fluid checked or changed. I flushed the entire system using my mityvac, removed the calipers, cleaned and rebuilt them, prepped the rotors, and installed all new Vesrah JL pads front and rear. I replaced the fluid with Super Blue Dot 4 fluid, and I finished bleeding the entire system following the correct procedure in my Honda service manual. The front brakes are awesome now, and I have good pressure on the rear brake lever, however when I was out bedding in the brakes, it is obvious that when the rear brake lever is depressed I can tell that it is only actuating the front 2 central pistons on the front brake, but the rear brake does not seem to be working at all. I will try to rebleed the rear brake, and only the rear brake, but I am very positive that I did it correctly the first time. Any ideas on what else it could be, and or why the rear brake has kick ass pressure sitting still but once I get out on the road it lacks any stopping power?

You guys should have seen the inside of the calipers and the ends of the brake lines at the banjo bolts, b/c they were filled with a creamy spooge (i.e. giz) like material, and the front & rear brake fluid reservoirs and the clutch fluid reservoirs were filled with all kinds of sediment and more spooge. I am glad I finally addressed the brakes, b/c they were in dire need of a full maintenance job.

 

always helps to bleed lines 'uphill' but linked brakes may be a different animal

 

The sludge like material was inside the calipers (i.e. behind the pistons), and the sludge was at the banjo bolts when I disconnected the lines from the calipers. Now maybe there is some leftover junk inside the lines, but the calipers and the reservoirs are certainly cleaned out very well.

I don't think the rear brake was hot when I was bedding it in. Heck, I was only on the road for < 5 minutes before I started bedding the front brakes, and then I moved to the rear. So I don't think it was a moisture issue, which I agree would make the brakes spongy if there was moisture in the lines. It was so weird hitting the rear brake and having the front end diving, as I was not used to that sensation at all. I will just rebleed the rear brake again and try it again. Gotta love LBS brakes.

 

Glockem,
I changed the Brake fluid in my 04 a couple of weeks ago and also felt the rear brakes were not working as well as they should. I ended up having a little air trapped in the caliper. The rear lever felt firm but it didn’t have as much effect as I remembered. If you don’t remove the rear caliper, and turn the bleeder pointing up per the manual, it’s hard to get all the bubbles out. Also check for air at the proportional valve; it’s the highest point in the LBS. As a side note, I don’t think the Mighty Vac worked well for the rear brakes. Next time I’ll just use two people and do it the old fashion way. I know you had to take things apart and introduce air into the system, but if you just swapping out the fluid I would just add new fluid as the reservoir got low and not bleed it dry.

Action

 

I did the rear brakes a while ago and you really have to follow the service manual procedure to the dot. There's a section where you cannot use a brake pump at all and you just have to do things the old school way and press the rear brake lever to pump air out of the system.

It took me hours to do it but take into account that was the very first time I ever did the rear brake and looking back into it next time I do it I'll probably take maybe 2 hours at most.

 

Ok, well I think I figured it out. I removed the rear wheel, exhaust, and rear caliper, and I think I immediately noticed the problem. Somehow even though I bled the rear brake, the piston side brake pad got twisted somehow and wasn't seated correctly in the caliper. So I removed the pads adjusted the pad retainer clips that seemed to be the issue, and then reinstalled, rebled the rear starting at the proportioning valve and proceeded rearward. I need to go ride the bike to test it out, but I know it is correct for sure as the pads are seated great on the rotor, and the feel at the brake lever feels great as well. I wish it wasn't raining, otherwise I would be out riding right now. Thanks for your ideas.

 

Make life easier, guys. Best invention since sliced bread:

Speed Bleeder Bleeding Brakes Bleeding Motorcycle Brakes Automotive Bleeder Screw Brake Bleeder

One person can bleed his entire system in minutes.

 

I found a vacuum bleeder didn't work from the proportioning valve and rear caliper. The vacuum tube collapsed from the suction without being able to suck the fluid through the very long brake lines. I had to pump the rear pedal, with the vacuum, to move the fluid.

There was a ton of air in that line (probably had not been done right by PO), so it took a while.

Also, the centrally located rear caliper means it's very easy for you (or the PO) to have gotten chain lube on the rear rotor, thereby contaminating the pads and reducing rear braking significantly. If the poor braking persists, consider replacing the pads and using brake cleaner on the rotor until the towels come up completely clean.