Advice needed for 5th gen brake bleeding

Hi everyone,

I am trying to put a 1998 vfr back on the road and am having trouble bleeding the brakes. The bike has 17,xxx miles and was rideable as purchased but ran rough and didn't start easily. I have already done a tune up, added a VFRness, replaced and rebuilt the forks (bent in an accident), greased the head bearings, changed coolant, added speed bleeders all around and replaced all the brake pads. Clutch has already been bled and the lever feels very firm. There is also a long list of missing bits and broken plastic to deal with in time.

Unfortunately the manual doesn't make much sense to me since I'm not using a vacuum bleeder. Bare with me as I try to explain.

I have already used a few bottles of brake fluid attempting the bleed the brakes and all fluid is coming out clear. I'm attempting to bleed in this order: Front right caliper top bleeder (pump at hand lever), front right caliper center bleeder (pump at foot lever), front left caliper top bleeder (with caliper removed and tilted to help air escape, pumped at hand lever and secondary master cylinder), front left caliper center bleeder (pump at foot lever), rear caliper front bleeder (pump at foot lever), rear caliper center bleeder (pump at foot lever), and then bled at the proportion valve (foot lever).

The rear brakes feels strong but the front lever is weak. I repeated this procedure when I continued to see air bubbles rising from the proportion valve bleeder, but I believe this is related to the secondary master cylinder. With all bleeders closed and pressing the rear brake lever firmly down I can hear some gurgling or squeaking in the lines up front. I can also hear something strange with the system closed and pumping the secondary cylinder manually. It feels like it's not moving much fluid, and appears to be moving barely any fluid at all out of the proportion valve bleeder when opened. However, pumping the secondary master cylinder appears to add air to the lines, because when I pump the secondary cylinder by hand and then press on the foot lever I get a lot of air out of the proportion valve. I have repeated this ad nauseum with four bottles of brake fluid to no improvement. The secondary master cylinder continues to feel like it hasn't been primed and just sloshes fluid back and forth, and whenever I pump the secondary and go to back to the proportion valve air bubbles still come out.

Any advice?

Looks to me like the secondary MC might be bad, but you really need a vacuum tool to refill the rear system properly. They aren't very expensive, and come in handy for lots of things besides brakes. 

 Don't forget that the front, and rear systems are completely separate hydraulically. Don't worry about the secondary bleeders on the front calipers when bleeding the hand lever. 

I manually bled my whole system. I find that nothing can get the brakes as solid as a manual bleed. Even when I use a vacuum or pressure bleeder, I finish off the bleed manually.

This can all be done by one person. The hardest one to bleed is the secondary cylinder on the left front caliper. I had to contort my upper body into a weird position to be able to crank on the rear brake pedal with one hand and crack the bleeder open and closed with the other.

I am not sure how long you bled your system, but It took me a full liter of brake fluid to get my system bled solid front and rear.

Thanks for the help everyone. I was able to achieve satisfactory results without a vacuum bleeder. It required having someone else pump the rear brake pedal while I held the secondary master cylinder on the front left caliper. With the secondary held under pressure it started to move a lot more air and fluid and everything seems to be pretty good now, or at least far better than it has been.

I just performed this task on Monday. I can't recommend speed bleeders enough. It sure did help me as well as making things go much quicker. Also works a treat when dealing with the SMC and the PCV/rear caliper bleed. Another thing that helps here too is a good lift. Being able to sit and reach under the bike and be in front of the rear brake pedal does wonders for ones back!

I just use a broom handle wedged against the peg.

Final bleeding is done manually the vacuum tool is just to get fluid in those long lines. 

I just use a Polish man  :biggrin: