|
|
|
Broken down pipe stuck
- Thread starter Cbr125guy
- Start date
Ok. First of all, like Wingboy said, do not take your calipers apart. There is a procedure for that, but I don't think it's a good idea or necessary unless you are trying to fix a specific problem.
To re-fill your now drained braking system:
1. Properly re-attach any hoses you have disconnected. To do this 100% by the book you would use new washers and torque the union bolts to I think 25lb-ft, but I don't have a service manual for a CBR 125.
2. Top up the master cylinder reservoir to full (to the full mark, not to the brim) with new brake fluid. If you somehow got your hands on DOT 5 brake fluid, do NOT use that
3. Lay the cap on top of the master (don't have to tighten it down yet)
4. Pump the brake lever until the lever drops significantly or you feel pressure. If the level dropped, go back to step 2.
5. If the lever is starting to firm up at all (still will feel squishy), now begin to bleed the system at the caliper. Attach your bleeding tool to the bleeder screw, and follow the instructions for the bleeding tool.
6. You are not done until the brake fluid coming through the bleeding tool hose is CLEAR of air bubbles AND the brake lever feels firm.
7. Tighten the bleeder screw, remove bleeding tool, tighten master cylinder cap.
8. Maybe bleed the caliper again in a week, to see if any bubbles have been dislodged.
To re-fill your now drained braking system:
1. Properly re-attach any hoses you have disconnected. To do this 100% by the book you would use new washers and torque the union bolts to I think 25lb-ft, but I don't have a service manual for a CBR 125.
2. Top up the master cylinder reservoir to full (to the full mark, not to the brim) with new brake fluid. If you somehow got your hands on DOT 5 brake fluid, do NOT use that
3. Lay the cap on top of the master (don't have to tighten it down yet)
4. Pump the brake lever until the lever drops significantly or you feel pressure. If the level dropped, go back to step 2.
5. If the lever is starting to firm up at all (still will feel squishy), now begin to bleed the system at the caliper. Attach your bleeding tool to the bleeder screw, and follow the instructions for the bleeding tool.
6. You are not done until the brake fluid coming through the bleeding tool hose is CLEAR of air bubbles AND the brake lever feels firm.
7. Tighten the bleeder screw, remove bleeding tool, tighten master cylinder cap.
8. Maybe bleed the caliper again in a week, to see if any bubbles have been dislodged.
Last edited:
If you are seeing bubbles coming up in the reservoir when you move the brake lever, air is getting out and brake fluid is getting in. Keep doing that.
Spilled brake fluid eats paint. Spread out a greasy towel underneath the vicinity of the master cylinder throughout all of what follows.
Now, keep in mind that air bubbles want to go UP. Before doing what follows, set the cover of the master cylinder back in place so that brake fluid doesn't spurt up and splash everywhere when you do this. Take your brake caliper off the fork, hold it oriented so that the connection point to the brake hose is the highest point, and push the pads and pistons back all the way. You are now pushing air bubbles out of the brake caliper. Re-install and repeat your wiggling deal. You may have to do this a couple of times.
After you have gotten air bubbles out of the caliper, you will have some remaining in the master cylinder. Carefully tilt the bike and turn the handlebars so that the vent hole from the master cylinder inside the reservoir is at the highest spot, and wiggle again.
To get the last little bit of air bubbles out of the caliper, there is a bleed screw on the caliper - but if you do the above steps carefully, you might not have to use it.
Spilled brake fluid eats paint. Spread out a greasy towel underneath the vicinity of the master cylinder throughout all of what follows.
Now, keep in mind that air bubbles want to go UP. Before doing what follows, set the cover of the master cylinder back in place so that brake fluid doesn't spurt up and splash everywhere when you do this. Take your brake caliper off the fork, hold it oriented so that the connection point to the brake hose is the highest point, and push the pads and pistons back all the way. You are now pushing air bubbles out of the brake caliper. Re-install and repeat your wiggling deal. You may have to do this a couple of times.
After you have gotten air bubbles out of the caliper, you will have some remaining in the master cylinder. Carefully tilt the bike and turn the handlebars so that the vent hole from the master cylinder inside the reservoir is at the highest spot, and wiggle again.
To get the last little bit of air bubbles out of the caliper, there is a bleed screw on the caliper - but if you do the above steps carefully, you might not have to use it.
Trials
Well-known member
Well you could push the pads all the way back (being careful not to damage the pistons or pads) and then back fill the system through the bleeder screw with fresh brake fluid. You will need a length of clear plastic hose and a big plastic medical syringe.
That will take about 5 minutes once you get good at it.
Some things are so much easier once you seen somebody do it once. You need a mentor.
Bleeding brakes from the bottom is a b*tch because air inherently rises.
That's why I always do the procedure explained in post #83 first, and reserve using the bleed screw until the very last step, to get out the last tiny stubborn air bubble out of the caliper. Frequently it's possible to bleed the whole system without ever touching a bleed screw by carefully paying attention to encouraging air bubbles to go up and helping them do so.
mistersouthpaw
Well-known member
R3s are cheap and fun as hel
Is there fluid coming out of the bleeder valve at the caliper? If so bleed the banjo bolt there is probably an air bubble at the top of the brake line and there’s isn’t a bleeder valve at the top. What you do is pump pump pump the lever and then crack the banjo bolt while holding the lever and then tighten banjo bolt at the master cylinder end of the brake line. Good trick for bikes without bleeders at the top
It's been my experience that reverse bleeding is often easier for front callipers on motorcycles. When I changed the master cylinder on my VTX last summer I spent an hour trying to bleed things the traditional way only to end up bashing my head into the wall after I could NOT even get the slightest bit of pressure at the master cylinder to even start to work the air through the system via the bleeder - even with my vacuum bleeder - it would just NOT flow past the master cylinder for some reason.
I fashioned a reverse bleeder out of a big syringe and some silicone hose that fit over the bleeder nipple perfectly and I had the system primed and done inside 10 minutes.
Should have just done it from the beginning but I was sure it was going to be a quick process with the vacuum bleeder tool. Not so much.
I fashioned a reverse bleeder out of a big syringe and some silicone hose that fit over the bleeder nipple perfectly and I had the system primed and done inside 10 minutes.
Should have just done it from the beginning but I was sure it was going to be a quick process with the vacuum bleeder tool. Not so much.
mistersouthpaw
Well-known member
Reverse bleed works good too. I duct tape my medicine syringe to my tubing because I’ve popped off the tube and made a mess in the past
mistersouthpaw
Well-known member
You can use acetone or nail polish remover on a q-tip with the caliper off the rotor to clean the caliper pistons. Keep an eye on the fluid level in the reservoir if you’re moving the *cleaned* pistons back in so it doesn’t overflow
I've used simple green and a tooth brush to clean them with good results...spray it, let it soak a minute, brush it up and thoroughly rinse the whole caliper by pouring clean water on it.
Taking the piston out if it isn't leaking is a whole lot of extra unnecessary work.
Taking the piston out if it isn't leaking is a whole lot of extra unnecessary work.
Trials
Well-known member
Tried that once, it melted the tooth brush.
Haha, I was using a scrubbing pad on some electronics* on the weekend and briefly used it with some cleaning chemical** that wasn't too specific about what was in it, but it's something that is clearly trying to dissolve the plastic bottle it came in. I remembered the problem with that when a bit of the cleaning pad started to melt
*bare GPU die with residue of gallium based thermal paste
**thermal paste softener & emulsifier
TK4
Well-known member
Sometimes the easiest thing to do is tie off the brake lever ( or pedal) so the piston is open and let it sit overnight.
That will let a lot of the trapped air escape on its own, and then you can commence the normal bleeding process.
I've done that a few times on especially stubborn cases, it saves a lot of yelling.
That will let a lot of the trapped air escape on its own, and then you can commence the normal bleeding process.
I've done that a few times on especially stubborn cases, it saves a lot of yelling.
I don't think you should use brake cleaner, and certainly not acetone, on the pistons as some of this will get to the seals and is not good for them. Use clean brake fluid instead, a toothbrush, a shoelace that you loop around and then saw and and forth or something similar etc....... You can get 99% of the crap off of pistons by doing this.
If the pistons can be pushed in by hand or with a lever using moderate force there is really no reason to remove them as it then just a make work project and then you have to refill an empty system.
mistersouthpaw
Well-known member
Non-chlorinated brake cleaner is acetone based. Perfectly fine for cleaning caliper pistons
bigpoppa
Well-known member
J_F
Guest
I'm thinking OP just wanted to take the caliper off to clean it
not actually get the pucks out, just an assumption
a lot of extra work but he will get a lesson in bleeding
and wouldn't surprise me if the sys needed a flush anyway
and brake clean is just fine to use on the caliper
mineral oil of any type is to be avoided
and it is the preferred cleaner to use on the pucks and inside the caliper body
to remove any mineral oil based substance and dirt
if the pucks are out you are not reusing the seals anyway
not actually get the pucks out, just an assumption
a lot of extra work but he will get a lesson in bleeding
and wouldn't surprise me if the sys needed a flush anyway
and brake clean is just fine to use on the caliper
mineral oil of any type is to be avoided
and it is the preferred cleaner to use on the pucks and inside the caliper body
to remove any mineral oil based substance and dirt
if the pucks are out you are not reusing the seals anyway
|
|
|
|
|