Yamaha big bear 400cc front brakes lock up the handle is stiff front brakes lock up the front brake handle is stiff - Motorcycles question. Front brake locked on Kawasaki 300 atv. Causing the suspension to become stiff. Or if the front Left side wheel brake pump does not respond. Nov 01, 2013 1992 Ford Econoline.
Bought bike few weeks ago. Lots of things just weren't maintained, but nothing badly broken. The brakes were working but the rear fluid was so badly burnt brown that I figured I'd flush and bleed both. Front resivoir looked clouded over, but upon opening I discovered a fluid that was the cloudy color of clear silicone, and the viscosity was more like 90 wt gear oil. Again the brakes worked.
Judging from the number of times I dumped the little bleeder bottle, I flushed about 375 ml through. That's enough for more than three full drains and refills. However, I can't build pressure now. I've pumped a couple hundred times and only clear fluid bleeds, but it just won't build pressure. Any ideas?Should I go ahead and disassemble the front caliper entirely and flush that too?
I'm getting low on 600 degree Motul brake fluid, and was hoping to avoid that since it has to be ordered.I've rebuilt brakes on my WeeStrom, old Triumphs (autos), so have a clue, but this one's got me stumped. It's as if the system is sucking air in somewhere, but it isn't leaking fluid anywhere except bleed valve. I bought a vaccuum bleeder, that works pretty well. I've had the exact same problem 2 times on my wr125, and different things solved it each time. The first time, I had to lean the bike way over, and give the front caliper a little tap.
Seems there was an air bubble trapped in there.Second time it took me leaning the bike over again, to the left, and tapping on the resivoir with a screwdriver handle. There was little bubbles caught up in there. And both instances are after fully bleeding the system (so I thought).Good luck! Issue Resolved! Removed caliper, brakehose, master cylinder, lever, et.
And laid on bench and blocked everything up so bleed nipple was lowest, master cylinder and a catchpan were highest, but not by much. Then pressed pads out far as possible and blocked w/ a piece of 3/16 aluminum flat stock incase calipers closed. Then started a Jamaican steel drum serenade of the wrenching gods on all metal parts.
![Atv Front Brakes Will Not Pump Up Atv Front Brakes Will Not Pump Up](/uploads/1/2/4/2/124273448/726720443.jpg)
Evidently the bubbles loosened because after pumping the first 2 oz of fluid in, the lever was able to close the caliper. I ran another 1.5 oz in before tightening the bleed valve, and reinstalled everything. Opened the mcylinder back up, topped off and after second round of pumping it started to build pressure. Checked mcylinder and it was still full. Job done, checked torque on everything, and will test tomorrow.
I am considering that but there is no reason why my efforts haven't worked. Every time I have reverse bled the system from the caliper bleed nipple there is plenty of brake fluid coming out of the master cylinder like a fountain, no air bubbles at all.
I am going to take the caliper to a garage and have them pop the pistons out with their air line so that I can check the seals. If the seals are obviously damaged I will replace them, if not I will also ask the garage to bleed it again.But they will only pressure bleed it which is what I have been doing anyway. One thing you could try: Lock the front brake lever in the fully pulled in position (use rubber bands, or pliers.) and leave it that way overnight.Sometimes that is enough for the air bubbles to make their way out of the system.If not, the syringe method is cheap and it does work.I started using it back when I had a yz250 and Yamaha was too cheap to pay Honda to use their patented direct brake line routing.So my YZ front line had a big loop around the caliper, which means that if you ever got air in the line, there was no way to get rid of it by just bleeding the brakes in the traditional way. Another update time! I have contacted the seller of the Brembo seals and he said that there shouldn't be any air bubbles around the caliper pistons at all.
I have disassembled and re assembled the caliper three times now and tried it with both the SM master cylinder and the TE one, the lever goes back to the bar on both, but it doesn't feel like there is any air in the system. There is moderate braking effort but not the stoppie pulling power I am familiar with. It could be that both master cylinders are worn out and the bubbles around the caliper are a red herring because the caliper isn't designed to be operated off the bike but I doubt it!Kinda typical, whenever I decide to do something fiddly like this instead of replacing the whole part it normally ends up with complications! As far as I know about fluid dynamics, if the master cylinder of the TE has a smaller diameter, it will have a longer stroke.
The stroke also depends on the ratio of the lever.I don't know what the problem could be, sorry I can't help you.BTW, have you disassembled the caliper opening it in two halves? Did you have to replace any gasket? Someone says you can disassemble and reassemble it reusing the inner gaskets and I'm asking just to double check because maybe I'll have to do that in the future. Another update. I don't know what to think now, after swapping the brake hose for the one from my TE setup, the lever goes all the way back to the bar but only with a good squeeze, almost as though the linkage between the lever and master cylinder isn't long enough to squeeze the master cylinder plunger all the way to where it is at full pressure. What doesn't help is that I can't remember what it was like before!
It is good enough to do a small stoppie at the end of braking now and my brake pads aren't the best after getting so much brake fluid on them either. I figure I will leave it how it is, still stronger than the TE setup when that's working properly.Theo, yes to both of your questions. There is a small rubber O ring on the top part of the caliper where the hose goes in, sealing the two halves.
I was careful to make sure that had not fallen out on each disassembly. This O ring does not come in the rebuild kit so you have no choice but to reuse it.
I need your help. I know there are numerous threads on this but I haven't found anything that will help solve my issue. 2001 Yamaha Kodiak 400 4x4. Just rebuilt the rear caliper and installed new pads. The problem is that it doesn't matter how much I bleed them, I only have very little brakes. I have a clear tube on my bleeder into a jar of fluid.
I am pumping the lever (have tried it slow and fast, it never gets hard), holding it in, cracking the bleeder, tightening the bleeder, releasing the lever. I have done this for about 6 hours total and have went through 2 bottles of fluid. What am I missing? Looks like the same basic rear master cylinder that we had problems with on Ktms.Seals would suck air,wouldn't build up pressure.
You can try a Mityvac,may or may not help on these small master cylinders.Plus do you have the caliper pistons pushed in too far?I've had that happen on some calipers as fluid may not have enough room behind the piston to build up.If it comes down to the master cylinder, rebuild kits cost close to what a new master cylinder does,at least at this site. Others may be able to help you better that have gone through this. Looks like the same basic rear master cylinder that we had problems with on Ktms.Seals would suck air,wouldn't build up pressure. You can try a Mityvac,may or may not help on these small master cylinders.Plus do you have the caliper pistons pushed in too far?I've had that happen on some calipers as fluid may not have enough room behind the piston to build up.If it comes down to the master cylinder, rebuild kits cost close to what a new master cylinder does,at least at this site. Others may be able to help you better that have gone through this.hmmm. I may try to push the piston out some. There's not much room with the new pads though.
Thanks for the ideas. I guess if that doesn't work, maybe the master is to blame. I mean, it should build up pressure until the lever gets hard. This is not regarded as good practice but it works. Clamp a pair of vice grips on the rubber pipe leading from the master cylinder so that they stop the flow of fluid. Open the bleed nipple, remove the clamp, press the lever down fully and refit the clamp, let the lever return then remove the clamp, do this several times, then tighten the bleed screw and try the brakes. Don't forget, the first couple of pumps may just be moving the brake piston(s) out.I will try that.
I don't care if it's frowned upon or not. As long as it works. Is your problem that the brake never gets real hard? Or something else? You didn't mention if you checked for leaks(brake leaks can be very very small, use clean paper towels to wick for fluid).
![Brake Brake](https://i.ytimg.com/vi/NUhOpYKmnYc/maxresdefault.jpg)
On to your problem if it is getting hard but not giving you good stopping power I would re-disassemble the rear caliper and make sure it does not have any issues(binding piston etc.). If you can't get a hard pedal I would do whats called a bench bleed on just the master cylinder(MS). You will have to remove the master cylinder assembly and hose from the caliper and then you take that over to the bench and you bleed the MS back into itself or you can do it into a separate container of fluid. Just don't let the reservoir go empty and pump very slowly and do not go all the way till it bottoms out or you could damage the seals. I suspect that when you disassembled the caliper air may have got back to the MS and sometimes trying to bleed the 'normal' way won't get it out. You will want to use a pair of hemostats to clamp down on the rubber hose near the caliper fitting so that you don't drain the hose after bleeding the MS keep the fitting submerged and put the hemostats on. Only remove the hemostats once you have reinstalled the banjo bolt into the caliper.
Then put the assembly back on the machine and bleed the caliper as normal. Hope this helps. Is your problem that the brake never gets real hard? Or something else? You didn't mention if you checked for leaks(brake leaks can be very very small, use clean paper towels to wick for fluid). On to your problem if it is getting hard but not giving you good stopping power I would re-disassemble the rear caliper and make sure it does not have any issues(binding piston etc.).
If you can't get a hard pedal I would do whats called a bench bleed on just the master cylinder(MS). You will have to remove the master cylinder assembly and hose from the caliper and then you take that over to the bench and you bleed the MS back into itself or you can do it into a separate container of fluid. Just don't let the reservoir go empty and pump very slowly and do not go all the way till it bottoms out or you could damage the seals. I suspect that when you disassembled the caliper air may have got back to the MS and sometimes trying to bleed the 'normal' way won't get it out. You will want to use a pair of hemostats to clamp down on the rubber hose near the caliper fitting so that you don't drain the hose after bleeding the MS keep the fitting submerged and put the hemostats on. Only remove the hemostats once you have reinstalled the banjo bolt into the caliper.
Then put the assembly back on the machine and bleed the caliper as normal. Hope this helps.I have done many things on many different types of vehicles but have never had to bench bleed a master. Have heard of it and it makes sense. I guess the reason I didn't think of this is because I have never done it. I will definitely try this because it may just give me back my sanity. Thanks a million, brother.