Rear Brake Soft, No ABS, Gen II, WTH?

[Mackeroni]

Have not been able to find the answers I seek.

Front brakes work great. (Thank God.) Wonderful stopping power. Rear brakes have been soft with very little stopping power for a few months. I bled the rears using the front right caliper lower nipple and the rear caliper nipple. No bubbles. Several times, I ran up to 30 mph and slammed on the rear brake to activate the ABS so I could bleed the rears again, and there was still soft braking and NO ABS action at all. I have no ABS lights on the dash.

Any ideas? Thank you.

Peace... Mack

 

[RossKean]

I suspect you still have a bubble. If they won't fully deploy, the ABS won't work - brakes have to get to the point of locking up.

Rear reservoir, right?

 

[rushes]

My 08 needs the rear brake bled if it's sits for more than a month. Been that way since I bought it.

I have bled it in every way possible for 11 years and it doesn't matter. I've not held it in the air by the front wheel, but I've thought about it...

Just bleed it again and ride..

 

[FJRLoonie]

Try doing the same on a patch of gravel, albeit a bit slower.

 

[escapefjrtist]

Bleed the system some more...

~G

 

[Geezer]

Others have reported this in the past. It has always surprised them that the first, or second, or third time bleeding the system did not fix the problem; however, eventually a thorough repeated bleeding has fixed it.

 

[Fred W]

Gravity. Its not just a good idea, its the law!

Problem with getting air out of hydraulic systems is generally because we are trying to move air bubbles down to a bleed point. Or the air is trapped in a loop (like near the ABS hydraulic block) that is higher than the bleed point. It can be done, but requires a great deal of fluid velocity to get those bubbles down and out, which is hard to achieve without draining the little reservoirs on our motorcycles and introducing even more air. Its a vicious cycle.

Reverse bleeding is an option but requires additional equipment. Detaching parts and rearranging them so the flow it upward will do it, but is a royal PITA. Most folks just keep working it until they get it gud enuff.

And of course the hydraulic complications of the linked rear adds to the challenge. No magic bullet, but maybe commiseration is helpful?

 

[BigOgre]

I've balanced a brick and hung heavy objects from the foot lever overnight a few times. I think it helped.

 

[Gitbox]

Get out on a smooth dirt road, take it up to 40 MPH or so and stand on that rear brake. That will tell you pretty quick if your ABS system comes on. Plus it's a little safer than gravel or pavement.

 

[Mackeroni]

I suspect you still have a bubble. If they won't fully deploy, the ABS won't work - brakes have to get to the point of locking up.
Rear reservoir, right?

Yup. Rear reservoir. Haha.

Peace... Mack

Bleed the system some more...
~G

Will try some more. Will enlist the wife to pour fresh fluid in as fast as I suck it out.

 

[Mackeroni]

Gravity. Its not just a good idea, its the law!
Problem with getting air out of hydraulic systems is generally because we are trying to move air bubbles down to a bleed point. Or the air is trapped in a loop (like near the ABS hydraulic block) that is higher than the bleed point. It can be done, but requires a great deal of fluid velocity to get those bubbles down and out, which is hard to achieve without draining the little reservoirs on our motorcycles and introducing even more air. Its a vicious cycle.

Reverse bleeding is an option but requires additional equipment. Detaching parts and rearranging them so the flow it upward will do it, but is a royal PITA. Most folks just keep working it until they get it gud enuff.

And of course the hydraulic complications of the linked rear adds to the challenge. No magic bullet, but maybe commiseration is helpful?

Will keep trying, but let me ask you a question. I've been using a Mighty Vac. Would just pumping the brake lever by hand be better?

Peace... Mack

 

[Auburn]

Look over on the FJRiders forum. RaYazerman put together a test switch and procedure to trigger the ABS system to flush it. I believe the switch assembly costs about $12 shipped. Well worth it and makes it a lot easier to get fluid through the ABS unit.

here is the thread over there

https://www.fjriders.com/forums/viewtopic.php?f=65&t=4069

 

[RossKean]

Will keep trying, but let me ask you a question. I've been using a Mighty Vac. Would just pumping the brake lever by hand be better?

Peace... Mack

I have never used anything except the "lightly pressurize (slight squeeze)- open bleeder - squeeze lever fully - close bleeder - (gently)release lever" method. I start by draining the reservoir, wiping out residue and fill it with fresh fluid. Usually pump a couple of reservoirs worth of fluid through and call it good for the next two years. Some people claim Speed Bleeders help but I have never found them to be necessary. Takes me less than an hour from start to cleanup to do clutch, both front brakes, linked front and rear. Try without the vac.

I only mentioned rear reservoir because one time someone (not me) couldn't figure out why they weren't getting any fluid through despite the fact that the reservoir was full. Turns out they didn't even realize that the rear brake has a separate reservoir.

 

[escapefjrtist]

<snip> Will keep trying, but let me ask you a question. I've been using a Mighty Vac. Would just pumping the brake lever by hand be better?
Peace... Mack

Oh hell yes! Throw the Mighty Vac back in the drawer and forget about it. Bleed the old fashioned way [through the linked RH caliper] for at least the equivalent of a full reservoir. After that, move to the rear caliper and put a few pumps through it.

Good luck!

~G

 

[rbentnail]

https://www.fjrforum.com/forum//index.php?showtopic=136000&st=0&p=834610&&do=findComment&comment=834610

 

[Fred W]

I’m a MityVac user too. They work fine, especially for just fluid exchanges where you aren’t trying to chase a bubble out. But to get the fluid flow velocity to clear air bubbles you need to take out the bleeder screw and wrap ONLY the threads with plumbing Teflon tape then screw it back in place. The tape will seal the threads from leaking air when you open the bleeder. There is also some thread sealants that you can buy that will do the job. You really want to open that bleeder up to get the flow you need and those threads will leak enough air to kill your velocity. Just don’t get the tape or sealant on the beveled end of the bleed screw.

 

[Intech]

Speed bleeders work best. No need for any help as you can pump away and add fluid at the same time.

 

[Mackeroni]

Rear braking is back!

I have at least 85% braking power back on the rear wheel. I am going to credit an unusual accidental process for my success. My wife kept the reservoir filled while I pumped my MityVac on the rear wheel caliper. I had everything hooked up and was laying on the garage floor to watch the progress. However, I had neglected to open the nipple fully. As I squeezed the MityVac, there was a very small flow of brake fluid coming out. After about 20 pumps, I realized my error. I had built up quite a vacuum. My first instinct was to open the nipple fully. As I turned it open, brake fluid started streaming out very quickly. My wife started pouring and within a few seconds the MityVac drain bottle was full. I buttoned everything up and went for a very pleasurable test ride. Nice to have the rear brakes and linked front brakes working again!

My theory is that the rapid inflow of fresh fluid chased the bubble through and out. I am not necessarily recommending this process. If my wife had glanced away for even just a second or two, the reservoir might have drained past empty as I opened the drain nipple.

Thanks to all for the advice, especially those who simply encouraged me to keep trying. I love to wrench on my own bike (and car), and in 42,000 miles I have done most of the routine maintenance myself. (I let someone else rebuild the front forks, adjust the valves and mount new tires.)

Thanks again, and peace to all!... Mack

 

[FJR Flyer]

Look over on the FJRiders forum. RaYazerman put together a test switch and procedure to trigger the ABS system to flush it. I believe the switch assembly costs about $12 shipped. Well worth it and makes it a lot easier to get fluid through the ABS unit.
here is the thread over there

https://www.fjriders.com/forums/viewtopic.php?f=65&t=4069

Just an FYI, a female electrical connector spade is the perfect size to jump the pins on the connect to engage the ABS test mode.