Brake Bleeding Tips

[FjrVfr]

After replacing seals on my left front (non-linked) caliper I've still got sponginess at the hand lever (GenII w/LBS & ABS). Here's what I've tried so far:

MityVac'd fluid out the bottom bleeder. After the second bottle, I just started reusing the same clear fluid. I've put that same bottle through the system 5 or 6 times now.

MityVac'd fluid out the right, top bleeder in case air magically traveled from one caliper to the other. To my knowledge these are the only two bleeders related to the hand brake (LBS remember).

Repeated one and two with the old squeeze-loosen-hold-tighten-release method. Probably only a bottle's worth out each bleeder.

Tapped on every fluid bearing component with the handle of a screwdriver: calipers, lines, banjo bolts, reservoir, etc.

Cracked the banjo bolts at the lever and the calipers while squeezing. I know those things are notorious for hanging onto bubbles.

Bungied the lever to the throttle after adjusting it to position "1" for the highest compression and left it overnight. I've done this several nights with the bars in various positions (full left, center and full right). Even sat with it like that for about an hour wrapping on it with the screwdriver.

Cycled the ABS system using "hydraulic unit operation test #2" according to page 4-62 of the manual. If you ever need to do this, a common blade connector from Radio Shack across the sky blue and black wires (thanks Ionbeam) is your friend. I did this about a half dozen times.

After that I'm out of ideas. I'd keep bleeding it if I thought the 46th bottle of fluid would magically do the trick. After a dozen or so I'm flirting with the definition of insanity. At this point I'd be happy to take it to the butcher dealer but I couldn't live with not knowing how they fixed it.

Any advice appreciated.

 

[Geezer]

I don't know what "hydraulic unit operation test #2" is. I suspect it is a mechanism to open the ABS so it bleeds along with the lines. What I did on my old Ford was to take it out and use the brakes hard enough for the ABS to kick in a couple of times, the blead it. I repeated this a few times until the brakes felt right.

Also, since you have obviously bled that caliper thoroughly, you may want to bleed all of the calipers one more time just in case some air got into the system and worked into one of the other lines.

 

[FjrVfr]

I don't know what "hydraulic unit operation test #2" is.

It's a way to cycle the ABS pump while the bike is parked.

Also, since you have obviously bled that caliper thoroughly, you may want to bleed all of the calipers just in case some air got into the system and worked into one of the other lines.

That's what I meant by right caliper, top bleeder in the original post. On GenII's the brakes are linked so the hand lever activates all six four pistons in the left caliper and four two on the right. I've now bled all of those - repeatedly. The other front right piston is actuated by the rear brake pedal which is fine. I'm fairly certain the two brakes (lever and pedal) use independent hydraulics.

Thanks though. I put a ton of fluid through the left one before I said "this can't possibly matter but I'll bleed the right side anyway." It didn't.

Edit: four pistons per rotor up front. I'll try cutting the pills in half.

 

[ionbeam]

Sounds like you have done all the right things but didn't get the expected results. Perhaps there are other things you need to look into, these may seem a bit gonzo but what you are doing isn't producing results so I will bring them up.

Are you sure that you are not loosing small quantities of brake fluid past the new seals or at the lines where they enter the caliper? Or, for that matter at any other hose junction that may have gotten stressed during the seal replacement.

In fiddling with the master cylinder (banjo bolt & bleeding) could something have happened to the master cylinder plunger to either cause air to get trapped or the seals to leak? Did the master cylinder get run dry at any point during the bleed process?

Just have to ask, what are you using for brake fluid? Ya never know...

I have to add -- is there a possibility that the brake lever is working correctly and the problem is that the feel isn't what you remembered or expected? You may need to do a compare with another FJR and see if you brake lever really is different. Hey, we are looking in the weeds now...

I just gots ta ax, why u changing da seals?

Ben Franklin says, "Insanity is doing the same thing over and over expecting different results."

 

[jcyuhn]

I couldn't get all the air out using just a mityvac either. I resorted to using the mityvac and conventional squeeze/turn bleeding simulaneously. Put the mityvac on the bleeder and pump it down. Then put a wrench on the bleeder (10mm, right?), apply pressure to the brake lever, open the bleeder, close the bleeder, repeat until satisfaction is achieved. Using both pressure and vacuum worked quite nicely, where either method individually left a distinctly mushy feel.

Only caveat - a quick squeeze of the brake level shoots a drop of brake fluid up and out of the master cylinder. You must keep the plastic cover on the master cylinder when bleeding this way. I bled the entire master cylinder once on both the left and right calipers, and all was good.

 

[FjrVfr]

Are you sure that you are not loosing small quantities of brake fluid past the new seals or at the lines where they enter the caliper?

I'm not sure how I would check that. I can't see fluid leaking anywhere and I've been riding it a lot since doing the work (they're not awful, just not FJR worthy).

In fiddling with the master cylinder (banjo bolt & bleeding) could something have happened to the master cylinder plunger to either cause air to get trapped or the seals to leak? Did the master cylinder get run dry at any point during the bleed process?

I don't think I ran it dry this time. I did when I bled them several months ago for routine maintenance but after bleeding they came back just fine. Any suggestions for how to determine if something [could] have happened to the master cylinder plunger to either cause air to get trapped or the seals to leak? If this were the case, what would the procedure be to correct it?

Just have to ask, what are you using for brake fluid? Ya never know...

Prestone DOT4 synthetic.

I have to add -- is there a possibility that the brake lever is working correctly and the problem is that the feel isn't what you remembered or expected? You may need to do a compare with another FJR and see if you brake lever really is different. Hey, we are looking in the weeds now...

We think a lot alike (which is at least making me feel better). There's a kid at work with an AE and I finally went over and - well there's no gracious way to say this - compared mine to his. On mine you can make contact with the throttle if you really lean into it. His is like Gibraltar. I don't think Godzilla could pull his back to the bar. Thank god today isn't Friday.

I just gots ta ax, why u changing da seals?

Longer part of the story: This started when I changed clutch and brake fluids at about 50K miles. No problems but I did notice uneven wear on the front pads. One was close to the metal. I think McAtrophy experienced a similar phenomenon. I ordered up new pads and installed them. Sometime later I had the wheel up and noticed it wasn't spinning freely. Also noticed the left rotor heating up a lot more than the right. My guess was that I didn't clean the pistons sufficiently when I pushed them in to replace the pads and introduced dirt. Much as I tried the toothbrush/soapy water/brake cleaner thing I couldn't get them to stop dragging. They don't drag now!

Ben Franklin says, "Insanity is doing the same thing over and over expecting different results."

Brother, don't I know it.

ps - seriously Alan, thanks for your help. Your posts are some of the most helpful on this forum and that's saying something.

Mark

 

[exskibum]

Well, I recall another procedure used by shops for really difficult bleed jobs. I had a similar problem on my old '97 Honda Blackbird, which didn't have ABS, but did have a linked brake system (with a known affinity for trapping bubbles somewhere obscure) and a shop did this:

They actually pumped clean fluid up through the bleeder valve on the caliper and then evacuated the accumulating excess from the master cylinder reservoir before it overflowed. I'd heard of the prrocedure before, but after trying almost everything myself and having them try to bleed the system the conventional way, this was what finally worked on that bike as I was getting ready to sell it almost exactly 4 years ago.

 

[FjrVfr]

I resorted to using the mityvac and conventional squeeze/turn bleeding simultaneously.

Now that's an interesting idea. Suck and blow at the same time. How can that not be fun?

How can today NOT be Friday?

...a quick squeeze of the brake level shoots a drop of brake fluid up...

You betcha. Hit the ceiling the first time I tried it.

Thanks!

 

[FjrVfr]

They actually pumped clean fluid up through the bleeder valve on the caliper and then evacuated the accumulating excess from the master cylinder reservoir before it overflowed.

Huh. That sounds like a smart way to go since you'd expect bubbles to want to go up more than down. Any idea what kind of pump can do this (and survive exposure to brake fluid)?

 

[wfooshee]

Hit the ceiling the first time I tried it.

I don't remember if I hit the ceiling the first time, but I did have the top bunk . . . . .

 

[exskibum]

They actually pumped clean fluid up through the bleeder valve on the caliper and then evacuated the accumulating excess from the master cylinder reservoir before it overflowed.

Huh. That sounds like a smart way to go since you'd expect bubbles to want to go up more than down. Any idea what kind of pump can do this (and survive exposure to brake fluid)?

Yeah, I believe that's the theory with the bubbles. Sorry I didn't stick around to watch them do what they did, or with what. I ASSumed they rigged a MityVac backwards like you would with a vacuum cleaner to blow air with the hose hooked up to the exhaust (picture an Electrolux canister vac with hose attached to opposite end), but to tell the truth, I've never gotten my MityVac (actually, I have a different brand) out to see if that could be done with it.

 

[Bustanut joker]

Hey buzznutts? Ya can't hook the Mity vac up backwards.. I just looked.

Damned sheepjumper. [SIZE=8pt]Just noticed the new av[/SIZE]..

:jester:

 

[TownsendsFJR1300]

On my aluminum Mity Vac, the port that is right is front of the gauge (capped with a rubber cap) is a positive pressure port.

It will not register on the gauge but when working the pump with the cap off it will put pressure out... Not much, maybe 5-10 psi...

 

[FjrVfr]

On my aluminum Mity Vac, the port that is right is front of the gauge (capped with a rubber cap) is a positive pressure port.

Mine's one of the low end plastic versions. I don't see a positive pressure port. Probably have to shell out some more quatloos for a fancy gizmo that I'll use exactly once in my life. Damn, it sure is frustrating.

 

[exskibum]

On my aluminum Mity Vac, the port that is right is front of the gauge (capped with a rubber cap) is a positive pressure port.

Mine's one of the low end plastic versions. I don't see a positive pressure port. Probably have to shell out some more quatloos for a fancy gizmo that I'll use exactly once in my life. Damn, it sure is frustrating.

Well, I suppose that gives you the old one to suck the excess outta the reservoir whilst the new one is pumping fluid from the bottom. (Now watch Bust make sumthin outta that. ) Sounds like it might best be a 2 person operation, but I'll sure be interested to read how you end up solving the problem.

 

[Bustanut joker]

Well, I suppose that gives you the old one to suck the excess outta the reservoir whilst the new one is pumping fluid from the bottom.

Intriguing.... I gotta admit I'm getting all tingly

:jester:

 

[PhilJet09]

We used to pump fluid up through the bleeder on small airplane brake systems, worked great. I used a metal oil pump can/oiler that you can get from most hardware stores. This one from HF looks similar: https://www.harborfreight.com/catalogsearch/result/?q=oiler

 

[scmagna]

I just watched part of a show this past weekend on the speed channel - those guys that build from the ground up and have every tool known to mankind. He showed a pressure bleeder that you connect to the caliper. I wish I could remember the brand, but he said it is the best way to bleed brakes. Makes sense to me.

 

[Peter Murray]

ALL caliper pistons must be fully retracted to insure all air pockets are removed.

This past weekend while adjusting my steering head bearings,, I introduced air into the clutch and front break resivors. The bars were laid over, as in upside down. Bled the clutch without problem. The front break lever still felt soft. At this point I pulled the calipers and seated the pistons , bled the system again with success.

Used the mityvac to bleed.

Hope this helps