2011 FLHX w/ABS: Rear Brake Pedal Goes to Floor, Doesnt Stop. Where Do I Begin?

[DrSpencer]

2011 Street Glide w/ABS, ~30K miles.

The rear brake abruptly stopped working. Pedal goes all the way down, but nothing, no stopping power at all.

The pedal cannot be 'pumped back up' to any level of firmness, whatsoever. Nothing but mush throughout the whole range of travel.

When coasting, if I stab the pedal all the way to the floor, I can hear the ABS chattering, like it normally would.

Master cylinder is full (brake fluid was changed at 15K miles), and no signs of fluid loss at the caliper, or anywhere else along the chain.

I should mention, this bike was issued a recall for some type of rear brake switch (located near the trans cover) to be replaced. I have not yet had the recall performed by the Dealer.

Where should I start?

Thanks

[Coyote]

New abs module. 

[DrSpencer]

New abs module. 

What makes you say that?

Is an ABS module a DIY project, or is a HD Digital Technician Dealer Tool required?

Thanks

[Coyote]

http://harleytechtalk.com/htt/index.php/topic,85858.msg969489.html#msg969489

[Smarty]

Just had a friend in Alabama go thru almost the same thing. His back brakes started getting really hard to push and finally the brakes would start working. It's a 2011 CVO Roadglide. Took it to Harley. My friend works for quality control with Hyundai and as luck with have it, he was at a meeting with the company that makes all the abs systems, for Harley also. Well, Harley had his bike for almost 3 weeks. They wanted the ABS module sent back before they would give him another one. Hmmm?  Anyway, the dealership ended up replacing the whole system including brake lines and rebuilding the calipers. The ABS module problem was the valve on the back brakes. Come to find out, if any part of the ABS fails, it is supposed to shut down, throw codes and show up on the speedo with a check engine light, and all brakes are supposed to work just as normal brakes without ABS. Now, you didn't hear this from me, but rumors thru un-named sources is that sometime in August there will be a huge recall on all ABS systems prior to a certain year. Evidently the program that bypasses the ABS isn't in the system for some reason. This sounds like a big deal to me.

[rbabos]

Just had a friend in Alabama go thru almost the same thing. His back brakes started getting really hard to push and finally the brakes would start working. It's a 2011 CVO Roadglide. Took it to Harley. My friend works for quality control with Hyundai and as luck with have it, he was at a meeting with the company that makes all the abs systems, for Harley also. Well, Harley had his bike for almost 3 weeks. They wanted the ABS module sent back before they would give him another one. Hmmm?  Anyway, the dealership ended up replacing the whole system including brake lines and rebuilding the calipers. The ABS module problem was the valve on the back brakes. Come to find out, if any part of the ABS fails, it is supposed to shut down, throw codes and show up on the speedo with a check engine light, and all brakes are supposed to work just as normal brakes without ABS. Now, you didn't hear this from me, but rumors thru un-named sources is that sometime in August there will be a huge recall on all ABS systems prior to a certain year. Evidently the program that bypasses the ABS isn't in the system for some reason. This sounds like a big deal to me.

Yes but look at the money they saved.
Ron

[markymark]

If there is a recall, look at what they will spend.

[14GuineaPig]

I have a couple of questions for the OP.  Does the brake light come on when you step on the rear rake pedal?  I ask this because the rear brake light switch is a pressure activated switch and if it lights the brake light that would indicate that there is some pressure when the pedal is pressed.  Have you tried bleeding the rear brake at the rear caliper bleeder screw?  If nothing happens there, have you tried bleeding the rear master cylinder at the banjo bolt that connects the brake line to the master cylinder?  I'm just curious if you have pressure at the caliper and at the master cylinder.  If you don't have any pressure at the master cylinder, then I would replace/rebuild the master cylinder.  If the master cylinder is working follow the brake line and check for pressure (bleed) at the ABS module input from the master cylinder and output to the caliper.  From what you stated, "no leaks & fluid is full", I would think the master cylinder is at fault.

[Buffalo]

Is there a chance that somehow the brake fluid used was the wrong type? It is supposed to be Dot 4 only for ABS systems. If Dot 5 was used, it would cause all kinds of problems. Buffalo

[DrSpencer]

I have a couple of questions for the OP.  Does the brake light come on when you step on the rear rake pedal?  I ask this because the rear brake light switch is a pressure activated switch and if it lights the brake light that would indicate that there is some pressure when the pedal is pressed.  Have you tried bleeding the rear brake at the rear caliper bleeder screw?  If nothing happens there, have you tried bleeding the rear master cylinder at the banjo bolt that connects the brake line to the master cylinder?  I'm just curious if you have pressure at the caliper and at the master cylinder.  If you don't have any pressure at the master cylinder, then I would replace/rebuild the master cylinder.  If the master cylinder is working follow the brake line and check for pressure (bleed) at the ABS module input from the master cylinder and output to the caliper.  From what you stated, "no leaks & fluid is full", I would think the master cylinder is at fault.

1) Haven't seen the brake light come on (haven't really looked for it, either). I will check on this.

2) When I changed the brake fluid (15K miles ago), I used a Motive Power bleeder. All my calipers also have Speed Bleeders, so I had a nice firm pedal. Until recently.

3) How to I bleed at the master cylinder, or anywhere else, if the rear brake pedal doesn't allow me to pump up any pressure (it just flops to the floor)?

Thanks

[DrSpencer]

Is there a chance that somehow the brake fluid used was the wrong type? It is supposed to be Dot 4 only for ABS systems. If Dot 5 was used, it would cause all kinds of problems. Buffalo

No, I checked this.

Thanks

[14GuineaPig]

If you can't develop any pressure at the master cylinder then replace/rebuild the master cylinder.  That should be your starting point, not the replacing the abs module.  Also from what I have read when the abs module fails it usually causes a hard pedal or lever that does not move.  That's the opposite of what you are describing.

[Just Nick]

If you can't develop any pressure at the master cylinder then replace/rebuild the master cylinder.  That should be your starting point, not the replacing the abs module.  Also from what I have read when the abs module fails it usually causes a hard pedal or lever that does not move.  That's the opposite of what you are describing.

You Nailed it. We just changed out a bad abs module and it was a hard pedal it was rock hard then it would just brake loose then hard again put a new module on and bled the system hooked it up to the computer for a abs bleed all worked great except the abs light so had to have the dealer use digtal tech to fix the light. but it sounds to me like you need a master cylinder rebuild kit because you can not make pressure at the master cylinder so how can the abs do its job if there is no pressure from the master cylinder

[FSG]

That should be your starting point

how can the abs do its job if there is no pressure from the master cylinder

perzacly   

[DrSpencer]

If you can't develop any pressure at the master cylinder then replace/rebuild the master cylinder.  That should be your starting point, not the replacing the abs module.  Also from what I have read when the abs module fails it usually causes a hard pedal or lever that does not move.  That's the opposite of what you are describing.

You Nailed it. We just changed out a bad abs module and it was a hard pedal it was rock hard then it would just brake loose then hard again put a new module on and bled the system hooked it up to the computer for a abs bleed all worked great except the abs light so had to have the dealer use digtal tech to fix the light. but it sounds to me like you need a master cylinder rebuild kit because you can not make pressure at the master cylinder so how can the abs do its job if there is no pressure from the master cylinder

Fair enough, that's where I'll start.

You say to get a mc rebuild kit, but do they even exist? How much more $ would a new rear mc possibly cost?

Any tips/tricks for installing a new mc on an ABS equipped bike?

Thanks, once more.

[14GuineaPig]

Just one more question ... are you sure the clevis pin (#8) and the push rod (#15) are still connected to the pedal?  The way you say the pedal just flops around had me wondering.

[FSG]

42932-08A KIT,    REPAIR,MSTR CYL,TOURING   MRRP 37.05

[attach=0]

[calif phil]

Just plug the port on the end of the master cylinder to see if it will build pressure.   No need to rebuild it if it's the ABS module. 


Harleypartscheap.com

[sfmichael]

Just plug the port on the end of the master cylinder to see if it will build pressure.   No need to rebuild it if it's the ABS module. 


Harleypartscheap.com

Yes 

[FSG]

Just plug the port on the end of the master cylinder to see if it will build pressure.

by all means the easy things first, but where would the fluid under pressure be going if it was the ABS unit ?

[Coyote]

Just plug the port on the end of the master cylinder to see if it will build pressure.

by all means the easy things first, but where would the fluid under pressure be going if it was the ABS unit ?

There is a cavity but I agree, if if the fluid level never drops (and isn't leaking), then it would seem to be the MC.

[DrSpencer]

Just one more question ... are you sure the clevis pin (#8) and the push rod (#15) are still connected to the pedal?  The way you say the pedal just flops around had me wondering.

Perhaps 'flop' was too strong a description. The linkage you illustrated is intact, but the pedal sinks to the very bottom of its travel, with minimal effort.

(nice pic, BTW).

Thanks

[DrSpencer]

Just plug the port on the end of the master cylinder to see if it will build pressure.   No need to rebuild it if it's the ABS module. 


Harleypartscheap.com

I like your thinking.

I know it's a long shot, but does anyone know what size bolt/thread I would use to plug the mc (saves me a trip to the hardware store)?

Thanks

[FSG]

Pretty sure it's 12mm, but don't use a plug to block the MC, use the banjo bolt with the sealing washers either side of a block of plastic/cutting board the same thickness as the brake line.

[14GuineaPig]

The way you describe what's happening there isn't any pressure.  Remove the banjo bolt completely and hold your finger over the hole and pump the pedal.  If you can't feel any pressure, enough to push the brake fluid past your  finger, replace/rebuild the master.

[Jaycee1964]

One question.  If the bike is turned off and battery disconnected does the brake pedal still go all the way down?  I too think it's a bad brake master....  But....

[Karl H.]

...When coasting, if I stab the pedal all the way to the floor, I can hear the ABS chattering, like it normally would...

I bet it's a faulty ABS unit! Otherwise why would the ABS valves chatter while the rear wheel rotates freely? What you describe seems to be the typical behavior of the brake pedal when the ABS unit is switched into service/bleeding mode by my Twin Scan III (or likely any other service computer). The complete volume of the master cylinder is taken by the accumulator 2 while valve V4 is open. Whenever the pedal is released (in order to press it again) the accumulator gets drawn empty by the rotating pump and the pedal can be stabbed to the floor again.



Karl

[14GuineaPig]

...When coasting, if I stab the pedal all the way to the floor, I can hear the ABS chattering, like it normally would...

I bet it's a faulty ABS unit! Otherwise why would the ABS valves chatter while the rear wheel rotates freely? What you describe seems to be the typical behavior of the brake pedal when the ABS unit is switched into service/bleeding mode by the Twin Scan III (or DigiTec). The complete volume of the master cylinder is taken by the accumulator 2 while valve V4 is open. Whenever the pedal is released (in order to press it again) the accumulator gets drawn empty by the rotating pump and the pedal can be stabbed to the floor again.



Karl

First, thanks for posting the diagram and an explanation of how the abs module works.  Do you think V4 could be stuck in an open position?  If the bike was OFF and the main fuse removed do you think that would allow the rear brake to work?  I'm asking because I'm trying to understand how the abs works.
If it is a failure of the abs module it would be the first failure that I have read about where the pedal/lever was not "frozen" or "rock hard".  If the abs failed it also did not revert to standard braking as it should and it did not light the abs indicator light according to the OP.  If the abs was serviced as recommended and it failed in this manner it should be reported to the NHTSA.  I'm waiting to hear what the OP finds.

[wholehog]

   I don't understand how Harley can get away with an ABS failure affecting the proper operation of the foundation braking system......that is like dangling a bloody body in front of a plaintiff's lawyer

somebody explain that.....

[Karl H.]

...If the bike was OFF and the main fuse removed do you think that would allow the rear brake to work?...

That's a good idea! It seems to be an electronical fault for me (not a stuck valve) because the pulsation can be heard. The hydraulic unit itself is basically fale safe. If the ABS-ECU ist off 12V power, the hydraulic valves - if not stuck - should allow a normal brake operation. So drawing the fuse should be a good test here! When the pedal is firm after drawing the fuse it's definitely a fault in the ABS-ECU.

Karl

[DrSpencer]

Finally got a chance to get back to the bike today.

Before turning on the ignition, I verified that the rear brake pedal linkage was properly connected (it was).

I then gave the rear brake pedal a few quick pumps with my hand, and I felt some slight pressure building. The pedal didn't go straight to the floor, as previously.

I then decided to check for any codes, and found the following:

C1094 [H] ABS: 'Front brake switch always on'
C1095 [H] ABS: 'Front brake switch open'
C1314 [H] ABS: 'Rear brake switch always on'
C1216 [H] ABS: 'Rear brake switch open'
B1155 [H] TSSM: 'Neutral switch input shorted to ground'

I cleared the codes and let the bike warm up.

The rear brake pedal responded positively to being 'pumped up'. It didn't seem to be as firm as it once might have been, but maybe I'm now being critical.

Went for a ride, and the rear brake operated as it should. ABS engaged when it was supposed to, brake light did not come on when brakes (front or rear) were applied, and it seemed to stop fine.

Rear brake pedal still seems a little softer than I remember..........

I should mention, the only thing that was done to this bike before the rear brake failed was I put on a new Fuel Moto 2-1-2 Jackpot head pipe (which replaced an identical FM head pipe that was cracked). I can't see how this would have any bearing on the rear brake failure, but I thought I should mention it.

Can anyone comment on today's discovery?

Thanks

[Karl H.]

Four inconsistent/conflicting ABS ECU related electrical failure codes! The ABS ECU monitors the brake switch inputs and sets the codes if required. It also uses the brake signals "to enhance the ABS performance and operation" (according to the manual). I still think it was a the ABS ECU not working correctly. 

Karl

[moose]

just happened to my buds bike a few weeks ago no rear pedal right down

wound up an abs unit replaced by the dealer.   we cut the old one apart and sure enough one of the pistons was jammed.  and it did not by pass the abs and work manually

[wholehog]

just happened to my buds bike a few weeks ago no rear pedal right down

wound up an abs unit replaced by the dealer.   we cut the old one apart and sure enough one of the pistons was jammed.  and it did not by pass the abs and work manually

gee....I thought the ABS was supposed to save your life, not kill you 

[DrSpencer]

I need some advice.

Should I install a new ABS ECU myself, then bring it to the Dealer and have hem bleed it with the Digital tech?

or

Should I just drop it off at the Dealer and have them do everything?

What would you do?

Thanks

[Coyote]

You can change the module easy enough. Then bleed it the best you can and take it to someone with the ability to do a digital bleed on it. There are several tools now to do this beside the dig tech.

[DrSpencer]

You can change the module easy enough. Then bleed it the best you can and take it to someone with the ability to do a digital bleed on it. There are several tools now to do this beside the dig tech.

Besides the ABS ECU module, are there any other parts I should order for this project?

Thanks

[Coyote]

You can change the module easy enough. Then bleed it the best you can and take it to someone with the ability to do a digital bleed on it. There are several tools now to do this beside the dig tech.

Besides the ABS ECU module, are there any other parts I should order for this project?

Thanks

No it's straight forward. you need to unbolt all 4 banjos. Then remove the rubber isolated mounting bolts. Remove the entire assemble and swap out the electronics on the bench. Assembly is just the reverse.  I made sure to have my vacuum hose next to each banjo as I removed them to clean up any fluid left from emptying the lines. Kept things neater that way.

[Smarty]

2011 Street Glide w/ABS, ~30K miles.

The rear brake abruptly stopped working. Pedal goes all the way down, but nothing, no stopping power at all.

The pedal cannot be 'pumped back up' to any level of firmness, whatsoever. Nothing but mush throughout the whole range of travel.

When coasting, if I stab the pedal all the way to the floor, I can hear the ABS chattering, like it normally would.

Master cylinder is full (brake fluid was changed at 15K miles), and no signs of fluid loss at the caliper, or anywhere else along the chain.

I should mention, this bike was issued a recall for some type of rear brake switch (located near the trans cover) to be replaced. I have not yet had the recall performed by the Dealer.

Where should I start?

Thanks

Just had a buddy in Alabama have close to the same thing happen to him. After an indy looked at it, he took it to Harley. Harley ended up covering everything since it was the abs. My understanding is the abs is supposed to be built where if it fails, you still have regular brakes. This was not the case with his bike. It's worth a shot. If need be, I can give you his number and name in an pm and get you two together on what happened exactly.

[rbabos]

Only a matter of time before MoCo get's sued over this. Not having a bypass for braking is clear negligence, any lawyer can have a field day with the design short cut. Plenty of internet reference material to prove the point also.  Like, who in their right mind designs a braking system like that, where if the ABS fails, so could braking. Sadly in some cases the flaw will show up when stopping is a matter of life and death.
Ron

[Ohio HD]

I know there are mixed players on the ABS / non ABS subject. The fact that HD's system is less than optimum, and in a few cases seen to be unsafe, I decided that one of the changes for my '09 will be removing the ABS. As they function today, I'm not sure there is much benefit to them being on there at all.


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