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Discussion Starter #1
So today i was riding home from work and realized i had no front brakes. My lever has full play and even when squeezed the whole way nothing happens. I can still roll the bike. The sight glass has a small air bubble, it has been extremely humid in wisconsin also lately. I dont know if those can cause this. Or could this be the spring in the master cylinder. I dont know much about brakes, but i know i need my front haha. Also how difficult is a rebuild if that is what is neccessary. Im planning on changing the brake fluid within the next couple of days i hope thats it. Thanks for the help Mick.
 

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Does the lever feel spongy when you pull it in or normal. And even tho you can spin the tire when the brake lever is pulled does it tighten at all or no change? Sounds like maybe you've got air in the system. How it got in there is potentially another problem but air will compress and you'll have no brake action. Good way to tell is to pump the lever a few times and see if by the 2nd or 3rd time the wheel starts to lock up. If it does, top off your master and with the cover off, crack the bleeders screws on both calipers and gravity bleed them for a bit then button it up and test again. What concerns me is, if you haven't opened the master cylinder to add fluid accidentally getting air in the system then you may a problem somewhere. So even if bleeding them fixes this now, be extra aware of how its working for a while. Keep us posted.
Dave
 

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My brake lever just moves freely there is no pressure at all on it. It was riding on my knuckles the whole ride home. I figured it was probably air or something. I havent opened the cover at all. How can air get into the system. Thanks Mick.
 

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Air could get if a seal is going bad or porous. Usually you'd see brake fluid seeping somewhere but in some cases it could suck in a little bit of air, usually down by the wheel cylinder on the caliper, after the brake is released. The air bubble you mentioned in the glass is a sign. But your lever should still have some feel to it. If it moves freely like its disconnected, I'm thinking its your master cylinder. There's a piston in there that directly contacts the lever. It could be stuck in. Sometimes a caliper could be frozen in the open position but again you should still have feeling in the lever espescially since our bikes have dual calipers. Its more common that they freeze in the closed position, cause drag and overheat the rotor, brake fluid and everything else but I'm sure you would have noticed that. Good luck and I hope this helps. I'm sure if I've mis-stated anything someone will help out and may offer tricks to test the components that I don't know about. No brakes is scarey. Glad nothing bad happened to ya.
 

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My brake lever just moves freely there is no pressure at all on it. It was riding on my knuckles the whole ride home.
Unless the brake lever tab pressing the master cylinder piston is not broken, then there is something wrong with the master cylinder itself. The master cylinder spring should return the brake lever to the released position regardless if there is air or brake fluid or both in the system.
 

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Discussion Starter #6
i dont know if the calipers are stuck i checked to see if they were rubbing, and no heat. If they are stuck do i just take them off and put a c clamp to them like when changing car brakes to free the piston.
 

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Good point about the spring in the master returning the lever pappa. Doubt your caliper is locked. Because you can spin the wheel and you said no heat build up. Lets concentrate on the master cyl for now. Does the handle spring back even though there's no pressure. Have you opened the reservoir yet to look at the fluid?
 

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Another thing to keep in mind is in the heat the tube expands...this can allow the fluid level to be low, which can lead to air bubbles entering the system. Check the levels and try to bleed. Start at the master (make sure its at the correct level and pump the lever with the master cover off till bubbles stop coming up), then front left side (if sitting on bike)hose near caliper then right and refill make sure not to let the master go dry or you gotta restart the process. Use a peice of 1/8 tubing to connect to the bleed valves and let it run into a suitable jar etc.
 

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^^^^

x2 Just had the same problem last month. Run the tubing into a jar that is about 1/4 full of fluid. Have the jar ABOVE the caliper.
 

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In case you don't know, brake fluid will damage paint. It would be better to work on the master cylinder with the bike on it's center stand and the tank and fender protected from drips and spills.
 

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Hmm, I wouldn't have thought to have the collecting jar above the caliper. Why do you say that?
 

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Discussion Starter #12
havent gotten around to changing the fluid between working and now rain. Got a nice three days off starting tomorrow so the bike is calling me. One more question since my brake lever just flaps in the wind and there is no way to pump the handle. once i open the master cyclinder can i push the spring back out or will gravity takes its course once i start pouring new fluid in. Thanks Mick
 

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Since you need to inspect the master cylinder, it is better to drain the old fluid first. Then:
  • remove brake lever
  • remove rubber boot
  • remove circlip
  • pull out brake piston & spring

Check that the holes from the brake fluid reservoir to the cylinder are not clogged up.

If you end up buying new parts like here or here (includes rubber boot and circlip too), lubricate the rubber parts with brake fluid before pushing the new piston to the cylinder.

And be careful to protect painted surfaces against brake fluid. Wipe off any spills immediately with wet/moist towel.
 

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Discussion Starter #14
Well i went to replace my brake fluid tonight. I opened up the bleeder valves and no fluid would come out. There is fluid it is amber colored. So does this mean another problem or could the spring piston assembly being worn out explain this as well. Thanks Mick.
 

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Well i went to replace my brake fluid tonight. I opened up the bleeder valves and no fluid would come out. There is fluid it is amber colored. So does this mean another problem or could the spring piston assembly being worn out explain this as well. Thanks Mick.
If the bleeder valves were not covered with rubber caps they could be full of dirt.
I`ve had to clean the bleeder valves out on my car before it would flow any brake fluid.
I used a small drill bit and twirled it between my finger tips to loosen the dirt and tiny rock chips.
 

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Discussion Starter #16
Thanks that helped. I cleaned the holes out with a small drill bit and got fluid to start coming out about 1/2 an inch. Since i have maybe 1/16th of an inch that the lever actually can apply pressure, it barely causes the brake fluid to move. I am now 95% certain that the spring and piston assembly is shot. Now i just have to find one and rip down my master cylinder unless you guys have any other thoughts. Thanks Mick.
 

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Sounds like you're definitely on the right track. Don't know if it would be worth just replacing the whole unit. There's a couple on ebay. The one linked below is $25 + 11 shipping. The parts for the ROUND reservoir M/C are:
43020-1054 piston $32.90 and 49016-1044 seal 6.95 from www.cheapcycleparts.com

the used one on ebay:
http://cgi.ebay.com/ebaymotors/1999...6625309QQptZMotorcyclesQ5fPartsQ5fAccessories

They should be interchangeable through most if not all years of our bikes. Someone please advise if I'm wrong. I know someone on here dumped their rectangle reservoir m/c for a round one. My 2000 has round.
 

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The rectangular MC reservoir was used from 1985 up to the 1990 models.

Round MC was used from `91 models to 2006. It uses a straight brake lever, compared to the dog leg bend in the lever for the rectangular MC.

They are otherwise interchangable between all models.
 

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The rectangular MC reservoir was used from 1985 up to the 1990 models.

Round MC was used from `91 models to 2006. It uses a straight brake lever, compared to the dog leg bend in the lever for the rectangular MC.

They are otherwise interchangable between all models.
Thanks for sharing that. i didn't know the levers were different. :smiley_th
 

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Discussion Starter #20
i have an 85 so mine is the rectangle. Can you exchange for the newer round on. Is there a difference, does it perform better. Or is it the same and just replacing the piston and spring would do the same job. Also if i upgrade to the round style does it just bolt on. Thanks Mick
 
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