Here's a post I made on the local forum about tips & tricks for bleeding brakes
most important - BE PATIENT !
getting air out of hydraulics requires patience.
Getting the big bubbles out is easy...the micro bubbles require time & patience & repeated bleedings
If you can use a clear line you can watch the teeny tiny 'micro' bubbles migrate in the clear tube
Those micro bubbles are the ones you have to get out for a rock solid firm brake lever
Use a good bright light so you can see the micro bubbles
Lately, after full bleed with fresh fluid thru out the system I have used the clear tube from the bleeder nipple back to the MC reservoir to finally eliminate the micro bubbles
(I zip tie the bleeder hose near the MC so it doesn't flop out of the reservoir- not too tight - just enough to hold the tube)
Also take the time to wait (patience) for ALL
the micro bubbles to rise in the MC reservoir before you pump up the lever for the next bleed
Look in the reservoir with a good light or flash light to see those little MF'g micro bubbles
If you have ever seen a master cylinder apart you will notice the piston has a hollow portion that the spring fits into.
That is a good place to trap air bubbles
I tilt the MC down (lever pointed more towards the ground) to allow the air bubbles to get out of the spring cavity. Some light tapping on the MC with the plastic handle of a screw driver seems to help move those air bubbles out so they can be bleed out of system
Did I say be patient?
time here is well spent
Brake Bleeding - Tips & Tricks Thread
Add your tips & tricks here !
Was talking to Adam tonight about brake bleeding & thought I'd share some tips & tricks I've learned over the years.
If you have your own tips & tricks please share them here !
Besides using a Mity Vac....here's some tricks I learned from people over the years for bleeding the brakes.
Push the caliper pistons all the way back inside the caliper & hold them open with a block of wood (leave old pads in place)
Pistons should be clean before pushing back into caliper to avoid damaging the seals !
I used a couple of 1/4" drive deep sockets cause I didn't have any wood that fit.
Leave the old brake pads in to keep all 4 pistons pushed back & in place.
Make sure the wood or sockets are in deep enough to keep the caliper pistons from pushing out crooked.
This way you have less air in the caliper to bleed out
Once you get the air out remove the wood (or sockets)
Pump SLOWLY so the pistons don't get hung up or come out crooked.
WATCH THE FLUID LEVEL in the resevoir - this is NOT the time to run out of fluid!!
I have done it 2 ways with the pistons pushed back.
1st with the calipers not installed (kinda of a pain in the a$$)
2nd time with the front wheel off & calipers installed
Bleed from the top to the bottom
1) bleed M/C
2) bleed furthest caliper
3) bleed nearest caliper
If you don't have a good hard feel to it repeat the process.
I have even bled at the M/C where the lines bolt up at the banjo bolt.
(this gets messy - put down plastic with rags on top to catch the fluid)
Have some rags ready to wipe up any spills FAST.
Use a wet rag followed by a dry one as the last clean.
Flush area with water after finished just in case you missed some brake fluid.
Do NOT get any water in the brake system - That would be BAD !!!
Brake fluid will destroy the paint ! Gotta get if off quick !
Oh almost forgot....
Pour the brake fluid SLOWLY into the reservoir.
If you pour fast it gets tiny bubbles in it.
(look very closely & you will see them)
bubbles will make the lever feel soft.
If you get bubbles in the reservoir just wait for them to rise.
Patience here is a good thing.
You should get a good hard lever when you do it right !
I have also held the brake lever pulled down snug with a bungee overnight to get bubbles out of the system.
(after repeated bleedings didn't get me a good hard lever)
Tapped the lines from caliper to M/C to help bubbles travel up to M/C.
Then re-bled entire system.
(there is some debate if this bungee trick works or not - seemed to help for me but maybe it was the re-bleed)
Time invested here will really help at the track.
You don't want a soft lever or any brake fade when you need your brakes the most !
The final bleed I did it the old school way - no mity vac
Pump lever 3 times pausing a moment at each out stroke of the lever
pull & hold tight the lever
Crack bleeder nipple valve just enough to get a good flow (spurt) of fluid but don't let the lever bottom out for more than a mili second.
DO NOT RELEASE THE LEVER until the bleeder nipple is fully closed.
Ideally you will close the nipple just as the lever reaches bottom.
releasing the lever sucks air back in the system (BAD)
The mity vac seems to suck a little air around the threads of the nipple
Some people teflon tape the threads but I have not have good luck with that - tape doesn't last with brake fluid
Want to try the liquid teflon & let it dry on the bleeder nipple threads to see how that holds up over repeated bleedings.
Something else you should do - clean your rotors.
With a clean rag use wet an area of the rag with brake cleaner
(try not to get it on the wheel paint or any other paint - might damage it )
clean each rotor repeatedly til the rag wetted with brake cleaner comes out clean
Then scuff your rotors - just the surface where the pad meets the rotor.
Be careful not to scratch the carrier or floating rivets.
They say to use a heavy scotch bright pad but I usually don't have any & use 100 grit sand paper.
What you are trying to do is put some light scratches on the rotor surface.
The rotors are pretty dang hard so you will not be taking metal off - just scratching the surface
This will help the new pads seat to the rotor.
Most likely your rotors have a shiny almost polished finish.
Scuffing the rotor surface will break the glaze, remove any left over pad residue, & allow the new pads to seat properly.
You can do this with the rotors on the wheel and the wheel in the forks.
Do both the inside and outside of both rotors.
Clean one last time with brake cleaner on rag, remove any lint & install new pads.
With new pads & scuffed rotors allow about 50 miles of street riding for break-in. (lots of light/medium stopping)
The goal is not to get them overly hot during break-in
After that you should be ready for 'performance' braking.
BTW when I change tires/wheels I will scuff both the rotors & pads to break the glaze & reseat them (some say it's not necessary)
I figure I have moved the pads/rotor placement ever so slightly they will have to re-seat so I scuff them to help speed the process
Helps them have a better 'bite'
The pros remove the rotors & bead blast them
Too bad I don't have a bead blaster !
Saw a guy at the track that used the concrete to scuff his pads
Crude but it works