ABS test help needed

[jerry1]

I have a 2006 ABS fjr. Front brakes controlled by the hand lever work great. Unified brakes controlled by foot pedal don't work very well . So when I do the ABS test #2 the result is as it should be.

ABS test # 1 where both brakes are applied with key off and then turning key on, one pulse is supposed to be felt at front brake lever which it is. Then two pulses are supposed to be felt at the rear brake pedal

which they are. However rear wheel does not turn on the first pulse but does turn on the second pulse. First pulse is weak and second pulse is quite stronger. Pedal operated brakes are not very effective at all out on the road. I have bleed the brakes with speed bleeders with pistons fully retracted and moving the calipers around in various positions while bleeding. Brake fluid flow when bleeding is quite normal. Master cylinder is not leaking down. So what do you think? I am thinking about getting a reverse bleeder. Has any one had good luck with them. I really don't think I have air in the system but something is definitely wrong. Help needed and appreciated.

Jerry

 

[RossKean]

When you apply the rear brake, you say that it is not very effective. Is there a lot of pedal travel or just not very good braking? When you bled the rear brakes, did you also bleed the right front bleeder? The lower right piston pair is actuated using the rear brake pedal and an air bubble in that part of the system will make the rear brake ineffective.

I have never felt the need to reverse bleed but then I haven't had any major brake issues. Have you tried to activate the front and rear ABS while riding? Easy and reasonably safe to do in a parking lot with a bit of sand on the surface.

 

[jerry1]

Yes I did bleed the right front bleeder (the bottom one). The abs won't activate front or rear on a loose surface.

Jerry

 

[mcatrophy]

Don't expect full braking from the rear brake pedal on its own, it only activates a little of the front brake's ability. The linking is more of a stability thing (or giving HD riders a little more than rear only).

Also remember that the ABS does not operate at very low speeds (something like 5mph), so if you're trying it at walking speed, it won't operate.

 

[BkerChuck]

I had a similar issue with my '07 earlier this year. With help of 2 friends we kept repeating those tests alternated with bleeding the rear master cylinder hoping to flush any blockages out of the ABS brick. It took quite a bit of time and probably a full quart of brake fluid but something inside finally broke free because we noted a rather large discolored chunk of ? pass through the bleeder hose and suddenly all was right with the world. I believe I hadn't exercised my ABS sufficiently and it had gone relatively unused for far too long causing one of those spools in the ABS block to hang up and possibly start rusting. This all happened after a hung up rear caliper wiped out a set of rear pads in under 8k miles. Caliper and rotor both replaced and brakes now bled through several times but I really should hit the ABS a little harder.

Best of luck and keep us posted.

 

[fjrjonesing]

Hey Chuck-

Can you PM me? I'm having identical issues with my 07 and would like to know specifically what you did.

I've actuated the ABS then bled the rear (which would lock up when I did this), but no joy. Next thing I was going to try involved light tapping with a hammer...

Jim in BR

 

[fjrjonesing]

Happy camper.

Problems started months ago when I stopped suddenly and the ABS kicked. When I ran the ABS test (or stopped suddenly), the rear brake would lock. Got to the point that the bike had no rear brake, and no fluid flowing to the rear caliper.

This morning, I attached the speed bleeder and commenced to light tapping toward the front end of the module. Nothing at first, then fluid flowed. Extensive bleeding and I had a rear brake again. Ran down the street and actuated the ABS several times, more extensive bleeding, and all is well. Apparently, whatever splooge broke free and clogged the works has passed through the system.

I was about to pull the trigger on the $1300 module.

Jim

 

[Jpridesdfw]

Interesting, I didn't see this before posting a similar question a few moments ago, though on a 2013 FJR.

Chuck, I'd also be interested in any specific details/guidance that you'd be willing to share.

 

[jerry1]

I received my reverse bleeder in the mail yesterday. Hopefully this will cure brake problem which I think is air in abs unit. Have to remove the speed bleeders of course in order to reverse bleed.

Jerry

 

[jerry1]

So I reverse bled the brakes , no help I am sure as no air bubbles appeared at the reservoir actually I think I may have gotten more air in the system as pedal feels more spongy.

The reverse bleeder I got costs $25 on Ebay I don,t like it as it moves but a small quantity of fluid at a time.

Jerry

 

[Harald]

The rear brakes on my 07 have never been very strong, requiring lots of foot pressure to seriously slow the bike. The ABS does work on both ends, but it's hard to engage on dry pavement. I ride down a very steep private road daily that often has gravel or wet leaves on it, so engaging ABS is pretty easy with those slippery conditions. Note that the ABS doesn't work below like 5mph and will lock up.

Not a big deal that the rear brakes aren't very strong because the front brakes are most of the stopping power on a bike anyway. But to get the most rear braking, I change the fluid every couple years using my Mityvac. It's very important to bleed the lower/rear bleeder on the right FRONT caliper first using the rear brake pedal and then bleed the rear caliper. Of course, to change fluid you just keep bleeding until fresh fluid is in the system. Then to make sure there's no air bubbles left, I hang some weight plates from the rear brake pedal overnight. By pressurizing the brake fluid, it helps to force any air bubbles up into the master cylinder.