I cant bleed my brakes

I have tried everything that I can think of to bleed my brakes with no success. I can pull the lever all the way to the grip with two fingers and you cant get the wheel to lock up unless pull the lever about a 1/2 inch from the bar. The adjustment screw is turned all the way in.

1. I tried the old method of pumping, holding and cracking bleeder.
2. Taking caliper off and holding above master cylinder then pump and bleed.
3. Forcing fluid up through caliper with syringe.
4. Opening bleeder and letting it drain out.
5. Putting hose on bleeder and looping it into a bottle of brake fluid (have plenty to spare at this point).

6. I have pumped the brakes then pulled the lever tight and strapped it to the bar over night. This usually works for about an hour or 2 of riding then it gradually falls off. I am pretty positive I dont have any leaks because there's not any fluid leaks and when I unstrap the lever it pulls back with the same amount of pressure it took to bring it to the bar.

6. Tonight I took the master cylinder apart, seals looked good and I also made a piece that is the size of the banjo fitting with no hole so I could test the master cylinder and it is fine. I bled the master cylinder and you could only move the lever about a 1/4 inch before it would lock up. Took the caliper apart and cleaned the seals, pistons and bore. Put everything back together and still the same thing.


Everything looks great but I cannot get a good brake for the life of me.

It has been like this since new and I just thought they sucked from the factory until I rode a ktm with the same setup and it was night and day different.

Is there something that I am missing or is this just the nature of the beast?

it realy sounds like you got air in the line! i havent had the pleasure of bleeding my smr brakes yet but i've done 3 sports bikes before and if you don't get all the air all the way out it wont lock up! sometimes it may take quite a few refills of the master cylinder before you get all the air out!

There are many post on this subject on ktmtalk. You can read for days. Many give up and just put a nissan on.

On my Huskys I have to do one thing I have not read anywhere else when bleeding with a syringe. I take the bleed nipple out of the caliper and run pluming tape around it. Otherwise I have found that air leaks in. This way I can work the syringe back and forth. When done I usally put a zip tie around the brake lever and let it sit that way overnight.

I had a bike project one time on a CRF and found the front caliper to be bad. I replaced the caliper and was able to get it to work. I even replaced the seals and guide tabs.

I did this once for a last ditch effort and it works..

Do you normal pressurizing and then open and closing the banjo bolt coming off the MASTER cylinder.. repeat two to 3 times.

then do the banjo bolt down at the caliper... Same method but 5-6 times.

Then do the Caliper itself the normal 4/5 times.

This has "cured" many many front and rear braking problems and never seen it fail yet..

Keep us posted it it ends your problem..

Chow, Carl

You've got air in there. I would take it off the bike and bench bleed it (This will keep the brake fluid off your bike too). Put the master in your bench vise (gently) preferrably with all of the hose below the fluid level. Sometimes this is not possible without loosening the banjo fitting and swiveling the hose end. I would try it without doing that first since it might let some more air in.

Now back (reverse bleed ) using your syringe. Turn the caliper so that any air bubbles can escape the piston bores and rise up the hose as you are pumping the fluid in.

Keep as much of the hose below the fluid level as possible. Use a big syringe so you don't have to keep detaching it. Try to fill the whole system in one shot.

That should get it damn close. You can go further by bleeding the banjos like Carl says.

I assume my ktm has the same set up, husky has behaved and ktm misbehaved over here. I found that just pushing the pads and pucks back into the wheel cylinder or caliper works and the ktm seems to misbehave perhaps once a year like that never going bad just being bad when it is time to load up or ride. Initially I used a c clamp with the wheel off but just using a screwdriver has done the trick the last few times. I didn't read you tried that in the first post.

After looking at the caliper with the pistons removed, I think this is my problem. I will have another go at it tomorrow and see what I come up with.

Yeah I have tried that one too. Tried so many just lost track. Maybe I should try again and hold the caliper at an angle so the air can escape the bore.

A big thanks to everybody for the great tips.

Later
Dave

I use a vacuum pump to bleed my brakes. It takes me about 5 minutes and it does a full flush of all the fluid. I do it once a year on all the bikes and the car and truck. Cost is around $30-40 at most auto parts stores. Hope this helps!

After you rebuilt your caliper you really let a ton of air in.

Next time bench bleed everything first and prefill as much as pracitcal. I've done this switching to a higher grade fluid and just let it sit for a few min's watching the bubbles come up to the master by themselves.

Bleeding at the banjos is not recomended and does no good.

Vegas Husky's recomendation is the next and final step.

Trust me that the bleeding on the banjos do no harm the crush washers but one day you'll remember this and say..Dang I wasted 3 weekends of good riding for nothing.. You'll see this in the factory pits at GNCC'c when the master cyclinder has air trapped to the hose..

Pulling the fluid is the best.. but if you don't plan on getting one ..bleed from start to end and the "when will I lose brakes again" saying would be a thing of the past.

I have see where front brake hoses were long and created a natural loop in the hose up top.. On those you could remove the caliper and leave it hang on the floor as you bleed it as it will take the loop out from up top and let the air come out(Thanks why M.Lafferty runs a shorter then factory hose up front) as it takes the loop and air out of the system..

As I stated in another thread....drop the caliper and let it hang. Loosening the bolt helps straighten the line and it optional. Trying to bleed past a washer is...um.

It's WAY faster to dangle the caliper, get the loop out of the line and watch the bubble come up in the resivour. Takes 5 mins. and no lost fluid.

Too each his own.

Tried again tonight and no luck. I hope this isnt insider trading, but you guys should buy stock in brake fluid

I might ding around with it this weekend and if not... I guess I have lived with it this long.

You are using the correct fluid? I saw a friend use dot 5.1 in a bike that called for 4.0 and this 5.1 fluid would not pump any pressure into the system.

I just read this on another thread :

You might want to check if the disk is bent. I noticed spongy front brakes on my TE, and it was because I tweaked my rotor just a tad. The mild taco/pringle shape pushes the pads out further when it spins, so you have to squeeze the lever further to get them to contact the disk.

Here is entire thread..posted just below yours
http://www.cafehusky.com/forums/showthread.php?t=3467

Its funny you mention that thread because I posted in it and thought I had fixed my problem. It worked for a few hours and it was back to normal.

I have to be sucking air in some place, because I have been pumping the brakes and spreading the pads apart for 2 hrs. and I get air up through the resevoir about every time. I am using dot 4 fluid and the rotor is not tweaked. I have a piece of 3/16 bar that I use inplace of the rotor and still no brake. Is it possible to suck air in and not leak any fluid?

Also do they make a rebuild kit for the caliper or do you have to buy the whole assembly?

I see said the blind man ...

Yes it only takes the smallest pinhole leak.

Yes

I remember trying to bleed the brakes on my Guzzi for a couple weekends.

I even bought a new caliper, new rubber hoses, etc. I made a pretty big mess of brake fluid, felt inadequate, swore loudly, slammed things on the ground in frustration.

Turns out there was a tiny, tiny leak in one of the metal brake lines...replaced line, bled right up.

good luck with it

Well I finally got the front brake working properly now. I ordered a new hose form Bottones and put it on and it didnt fix anything. So I took the master cylinder off the wifes bike and the brakes felt fine so I ordered rebuild kits for the master cylinder and caliper. I put them in last night and everything works fine.

I replaced the hose first because I thought I may have damaged it after a pretty good crash last year. I couldnt get any air through the bleeder but when I would pump the brakes then spread the pads apart I would always get air up through the master cylinder. So after that episode I figured it was probably the seals on the piston allowing air in the system.

For anybody that ever wants to replace the master cylinder piston, I found it is best to take the caliper off the fork and pump the pads till they touch and then when you reattach your master cylinder to the brake line just spread the pads apart and that pushes all the air back to the top.