Traumahawk
Well-Known Member
First of all......has the master cylinder been bleed? When I changed my brake lines.....I had to pump the master cylinder probably 75 times....before it started pushing fluid down to the brakes.
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Like Eric said, you might give the old fashioned way a try, and bleed from the top down. When I've had my handlebar master cylinder off, I get much better luck if I first bleed it with the brake line disconnected from it. (careful of spills). It seems to "bench bleed" much faster for me that way. Then I reconnect the brake line to finish bleeding down to the front wheel bleeders.
blaxmax
Well-Known Member
Have you ever used one of these? It has never lost a drop for me. Just put the end with the hose over the bleeder screw open the screw and pump.
http://www.ebay.com/itm/Mity-Vac-Va...1669751390&pt=Motors_Automotive_Tools&vxp=mtr
http://www.ebay.com/itm/Mity-Vac-Va...1669751390&pt=Motors_Automotive_Tools&vxp=mtr
Basically same kit I have which works well.
I had big problem with bleeding the brakes and clutch on the vmax. It was taking to much time manually. Even bleeding the air at the banjo bolt. About 3 years ago.
Sometime I'm not why it be can easy or time consuming....
I starting using flavor extractor it pushes the fluid up - this works great.
Then I started using my AC vacuum pump witch takes at the most 1.5 to 3mins at the most on each bleeder valve.
I been using the vacuum pump for years on cars to.
https://www.youtube.com/watch?v=ZViG9FMXhzw
Sometime I'm not why it be can easy or time consuming....
I starting using flavor extractor it pushes the fluid up - this works great.
Then I started using my AC vacuum pump witch takes at the most 1.5 to 3mins at the most on each bleeder valve.
I been using the vacuum pump for years on cars to.
https://www.youtube.com/watch?v=ZViG9FMXhzw
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Harbor Freight Tools sells the Mityvac, a great tool, I have two, one is new in the box. I bought it because I had to use a rebuild kit on the first one, and I got the second for whenever the original didn't 'take' the rebuild. The first one must be about 25 years-old by now.
I have used the 60 cc syringe to push the fluid up, same principle as the turkey baster. On my VMax, I find myself using the syringe/push method more-than the Mityvac/pull-method.
I have used the 60 cc syringe to push the fluid up, same principle as the turkey baster. On my VMax, I find myself using the syringe/push method more-than the Mityvac/pull-method.
I did try with syringe from down to up. No luck. Im giving up and give this task to bikeshop..dont like it at all, i have allways done my own maintaining on my bikes. Well, sometimes its better to give up..maybe [emoji30]
Traumahawk
Well-Known Member
when I changed my brake lines......it took about 75 squeezes....to actually start building pressure. I was certain that I had done something wrong. I would do about 25-30.....and walk away....and come back. After doing that a couple of time....it FINALLY started building pressure. The old fashioned way was to tie a rag around the lever....and leave it for the night. It would allow air to finally escape the system.
If you have both bleed holes free and open in the master cyl, then there are only two places for the fluid to go whether it's up or down movement. If you have internally-collapsing lines then the fluid may be going into pockets in the failing hose. Debris from the components which are failing could be clogging the bleed holes in the floor of the master cyl. Normally, you wouldn't be able to push/pull fluid if the hose was that bad. I've had internally-collapsing hydraulic lines on cars & trucks, and you simply replace them, and bleed any residual crud out until the brake fluid is crystal-clear, w/no coloration.
It is possible that a bubble could get stuck someplace, sometimes lightly-tapping on the area where you suspect the bubble to be lodged may help it to move-along.
Really though, my best experience has been pushing the fluid up. You should be able to get any stubborn air bubbles out that way. I like my Mityvac for the brakes, especially dual discs, but for some reason I can bleed my clutch better/more-quickly via the syringe. Even after bleeding via the syringe, you have to squeeze/release the lever repeatedly, but not-long after you do that a few times, you should feel the pressure of the slave cyl pushing the clutch spring, or the brake pads moving to the rotor. I usually 'fan' the lever rapidly until I sense the pressure build. A quick check for the fixtures being tight, clean-up any residual fluid, and let's go.
It is possible that a bubble could get stuck someplace, sometimes lightly-tapping on the area where you suspect the bubble to be lodged may help it to move-along.
Really though, my best experience has been pushing the fluid up. You should be able to get any stubborn air bubbles out that way. I like my Mityvac for the brakes, especially dual discs, but for some reason I can bleed my clutch better/more-quickly via the syringe. Even after bleeding via the syringe, you have to squeeze/release the lever repeatedly, but not-long after you do that a few times, you should feel the pressure of the slave cyl pushing the clutch spring, or the brake pads moving to the rotor. I usually 'fan' the lever rapidly until I sense the pressure build. A quick check for the fixtures being tight, clean-up any residual fluid, and let's go.
Hellion
Well-Known Member
If you tried it with the speedbleeder in the syringe shouldn't work. If you have the old bleeders try cleaning them up and put telflon tape on the threads and try the syringe again.
Ok. Bleeders are brand new, but not original... threads dìd felt loose.. Good tip, mayby I'll give it a one more try [emoji52]
Solved. I had right side saddle half with bleeder in left hand side and vice versa.. so bleedeing valve's was at the lower part of saddle's in both sides.. so it was my bad in saddles assembly..first time for everything
Traumahawk
Well-Known Member
Well atleast you found out what the problem is.....and thats the main thing....etc.
Yeah..at least i thought so also. There is something weird in main cylinder.. it does create pressure, but when brake leaver is released it creates vacuum into the system and pull brake pistons back in. Now is already second repair kit installed and second bikeshop and second pro bike mechanic investigating system. Cant understand this..so simple system... maybe its time to upgrade to newer bike..
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The pistons are SUPPOSED to retract (a little anyway). This keeps the pads from continually rubbing. They don't retract from vacuum. They retract due to the square cut rubber seal. It allows the piston to pass through it as the pads wear but they retract back when pressure is released.
falling
Well-Known Member
One thing I always do is add a double banjo with a bleeder to the block where the three lines come together. It's the best way to get air out of that block. You'd be amazed what a difference it makes. There's just no good way, other than that, to get all the air out. Shindy makes a nice one.
When prepping KTM race bikes, I'd also always take the banjo bolt and drill another hole in it, perpendicular to the factory hole. You can't always guarantee that the hole feeding to the line is facing up. I'd only do this on Steel or Titanium banjo bolts though. The KTM BREMBO brakes are awesome...until one microscopic air bubble appears, then they go to mush.
For bleeding, I use a mighty vac.
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When prepping KTM race bikes, I'd also always take the banjo bolt and drill another hole in it, perpendicular to the factory hole. You can't always guarantee that the hole feeding to the line is facing up. I'd only do this on Steel or Titanium banjo bolts though. The KTM BREMBO brakes are awesome...until one microscopic air bubble appears, then they go to mush.
For bleeding, I use a mighty vac.
Sent from my iPhone using Tapatalk
Gbianchi
Well-Known Member
Didn't see this problem, changed brake fluid in front brake by bleeding no problems but now the bleeders are leaking slightly, how tight should I go to stop this?
They should be snug, but I don't (over) 'tighten' them. You may have some piece of grit or something under the bleeder, sounds like you need to better-flush the system.
The brake system on a VMax is about as-simple as it gets, considering the speed rated top end was supposed to be 149 mph. I haven't ever been on one to be timed in a half-mile, but I expect that a good stock VMax would do probably right-at or over 140 mph in a standing-start half-mile. Stopping from that speed with the 1985-1989 brakes would be doable, but I would much-rather use the 1993+ 4 piston calipers and HH pads to do the same feat.
The brake system on a VMax is about as-simple as it gets, considering the speed rated top end was supposed to be 149 mph. I haven't ever been on one to be timed in a half-mile, but I expect that a good stock VMax would do probably right-at or over 140 mph in a standing-start half-mile. Stopping from that speed with the 1985-1989 brakes would be doable, but I would much-rather use the 1993+ 4 piston calipers and HH pads to do the same feat.
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