In The Shop: ABS Modulator Failure

One increasingly common issue that Harley Davidson owners have been facing is ABS module and modulator failure. Dot 4 brake fluid will absorb moisture over time. If your Harley is stored outdoors or in a humid environment, contamination of the fluid may happen even sooner. The moisture will eventually contaminate the internals of the ABS modulator. When this occurs, the front or rear brake lever becomes rock hard and actual brake function is nonexistent.

There are countless vehicles on the road, other than Harley Davidson, that utilize ABS systems and Dot 4 brake fluid. It is unsettling to us why Harley Davidson is, seemingly, the only vehicle manufacturer failing in this area. We realize that Dot 4 attracts moisture, but what is the engineering flaw that allows moisture to breach the sealed brake system? If you think about it for a minute, the answer is in a flawed brake modulator design. Harley was using Dot 4 in their brake systems, without issue, for years before Harley ABS models were produced and released to the public. When ABS was added, a module and modulator were added.

Harley ABS

The Harley ABS modulator is the only added component to the physical, working, ABS braking system (also added electrical: ABS sensor & module, and a magnetic wheel bearing). Being that the modulator is the only added component in contact with the brake fluid, it has to be the culprit. Rather than issue a recall, Harley’s solution to this issue was to send out a mass mailing to owners.

The letter stresses that owners have their brake fluid changed right away if it has not been changed within the last two years. Then, the fluid needs to be changed every two years after. The kicker, of course, is that the brake system can only be correctly bled with the dealership’s Digital Technician (or at a shop that has the Centurion Super Pro software – or the Twin Tec software).

Related Video: Bleeding ABS Brakes

Old Unit vs New Unit

A Disappointment from the American Company that We Love

If HD has not yet engineered and manufactured a correct Harley ABS modulator to replace the failing unit, it might be good business to change brake fluid for free until a recall can be issued and a replacement unit can be installed. That is, obviously, just our opinion. All that being said; we’ve been increasingly busy repairing this ABS issue. We have empty oil cases, with bad ABS modulators spilling out of the tops.

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56 Responses to “In The Shop: ABS Modulator Failure”
  1. Brad

    I had my brake fluid changed twice and brake system checked several times on my 2012 Ultra before they finally replaced the the rear brake pads and the pad material was a bit soft and spongy. The people at the dealership said they had never seen this before and that the pads must have got something corrosive on them that did that. A week later someone traveling through from out of state stopped at this same dealership to have the brakes checked. He was saying that they just all of the sudden would not work. His rear pads were soft just like mine. Has anyone else seen this problem and have any advice on how to prevent it. It is very scary when your rear brakes start to grab and just let loose and you continue to roll through intersections.

  2. doug

    if the fluid is changed when it should be, does this problem still exist? thanks for a great topic

    • Jason

      I know this is a bit old, but I wanted people to know that I created a DIY style app that allows HD owners to properly flush their ABS equipped bikes themselves. Our product does exactly what the dealership tool does at a fraction of the cost (and you don’t need to take the bike in of course). Pays for itself in one use (I flush my own bikes annually to help avoid the dreaded HCU issues mentioned in this article):

      MUCH cheaper than anything else on the market to perform the ABS flush routine.

  3. Edward Thomas

    I reported my crash due to loose of brakes to National Highway safety . Harley dealer charged for changing fluid. This might be my last Harley. Thanks for your info.

  4. Arthur Williams

    Looks as if Harley has decided not to do us owners any favors.
    Same old song, Harley will never admit to responsibility for their failures.

  5. Matt B

    I own a 2013 super guide with abs never received a letter from Harley ( was bought new )

  6. BWest

    Happened to me on a three year old Ultra. $1200 bucks later I have a new poorly designed part is installed and the bike is for sale. Sick of being raped by Harley snd their increasing efforts to produce bikes only they can repair. Checking out Induans’ rep now.

  7. Jones John Lloyd

    2009 Road King Classic, abs unit failed in second year, I don’t trust my dealer here in Houston, They left a battery wire off my led lights which caused them to acquire a ground through the engine light system. I removed all these lights only to find out Woodlands HD technician left the wire off during battery replacement, and battery was not bad just needed charging. Where and what tool do you suggest to bleed brakes myself, I am an aircraft technician??

  8. Dennis Boseley

    I have a 2010 ultra and had the rock hard brake lever so I got brake lines for a older model and bypassed the abs now I have good bra

  9. Re-Pete

    I have an ’07 Road King Police with ABS. I’ve had the bike for 7 years, and never had any brake problems. Do I have a weird system, or am I just lucky? Bike is garage kept, and I live in Florida.

  10. rhonda bowling

    hey guys
    top of the mornin’ to yah and thank you for bringing up this subject. I have a 2011 FLHTCU, I bought it 3 years ago at baton rouge HD, I never received a notification about this problem, I was heading to church at the club and all of a sudden I no longer had front brakes, I was on the freeway going the speed limit ( of course)…(LOL) imagine my surprise when I had to slam on my brakes to avoid the moron who crossed into my lane and cut me off !!!!! long story short….good thing I had good rear brakes, I thought I could maybe fix the problem by bleeding the front brakes to see if Maybe the ABS module would work
    waiting for an answer and thanks for this great website, I love the videos and all of the great advice from you guys
    keep wrenching
    Sgt. B

    • Customer Service

      A recall has recently been issued for 2008 to 2011 Harley’s with ABS.
      We highly suggest calling your dealer and insisting that they pick up your bike “that you could have died on”, so they can correct the problem (also free of charge!)
      They should pick it up for free because of the recall & circumstances.

  11. Tim

    Went to the local delaer for the saftey recall “Brake fluid flush” Had no indication of an ABS failure everything looked to be working before I went there. Now I am told the ABS selinoids are inop and of course HD will not replace the failed ABS module. So now I am told I my brakes will work normal without abs and I have an always on ABS idiot light. Before even touching my bike the Service rep says that they had one they flushed and it went bad later and parts would costv 700 but they don’t have any in stock. After trying to flush mine I get the story that mine is faulty now and I get PO’d and tell them don’t do anything don’t even order parts. Ive been rigding for 30 years and I’m finally fed up with Harley Davidson as a corporation. They have forgotten where they cam from and who made them who they are. Its all about making money of off the sheep now. I woun’t cast my shadow in a HD dealer ship againand plan to go to an independent mech. There are plenty around that still have there heart in the right place.

    How can I get a replacement ABS module without going through the dealer now. I guess they will go fast as I am not the lob]ne ranger with this problem that was a fresult of my own neglect to change brake fluid every 2 years> grrr

    • Tommy

      Got a 08 Ultra and got the letter from Harley….took it in with no problems and while waiting was told that the module is bad….said I would have to leave it, told them no, they put it back together and told me they unplugged the mod and removed the fuse for the ABS….and they would order the part that would be $650.00 I left , came home and put a fuse back in and plugged the mod back in and went out and tested…all back to working …I went by a local independent and ran it by them, he called BS as well, if there was a problem there should have been a light / code….nothing. this guy has the software ordered to do the flush and checks, will be going back to them even though I will have to pay for the flush. If and when the module is or goes bad , are there any web sites that offer after market modules. .

  12. Dan

    Received the HD brake fluid recall the week my ABS module failed on my 2009 FLHTCU. Is anyone aware of anyone having success with having HD pick up the cost associated with this repair?

    • Gary Kirkindoll

      Exact same story on my 2009 FLHTCU. Got the recall notice a few weeks ago. Got on the bike yesterday to take it to the dealership to have the recall service done and the front brake lever will not work. Almost wrecked pulling out of the driveway. The bike had always been serviced at all intervals by my Harley Dealer. Pulled the bike back into my garage and am trying to find out if they will repair whatever is going wrong. From reading the forums, this appears to be a common problem. This is scary because someone is likely to get killed. Can only hope Harley is going to make good on this.

      • Danny C

        I just left Emerald Coast HD in Fort Walton Beach, FL. I took it in because I had lost my rear brakes. They diagnosed the problem, checked my records on the computer and informed me that the module was bad and it was covered under the extended warranty.

  13. Kenneth Beckham

    I too have a 2012 Road King, Classic model. I did recieve the recall but my VIN was not on the list and due to wifes extended period of illness was unable to take the motorcycle in even though it was not on the list. About a month ago I needed to get rx for my wife and decided to take the motorcycle for the 14 mile round trip. First indication of a problem was at a stop sign about 1 mile from destination when the rear brake pedal locked. I kicked it once to make sure it was in fact locked and it worked. On the return trip another lock of the rear brake pedal but this time it would not release. I made it home using the gear box and front brake. Now I am seeing the 2012 did not make the NHTSA list. My question is are the 2011 and 2012 the same exact part? I can see where a production run for the 2011 and earlier models may have resulted in excess inventory at HD and they just used them up on 2012 and possibly later models. I have talked to my mechanic and he ,like most others, agrees the flush is not a fix. The problem is corrosion which could be a dissimilar metal issue accelerated by moisture. The flush could have included a “rust remover” type fluid that would release the stuck pistons which would extend the life of the oem part but not cure the problem. Can’t believe any mfg would take that chance much less their insurance company which could be HD self insured. Long story short I now have to go through the dealer/company process which will be time consuming to say the least. I will also go through the NHTSA process to try to get the recall extended but more importantly to up grade the module itself using corrosion proof/resistant metals. I went through a similar situation with starter issues where the starter would slam internally due to lack of lubrication at a critical point , don’t recall the part name, Dealer worked on it 3 times replacing different components until HD came up with a simple lubrication fix. By that time my VIN had been flagged on the dreaded list. I imagine that is going to bite me again but we’ll see. This time I will try it without saying “legal”.

  14. Donnie

    Just took my ’08 FLHTCU in for the recall last week. My dad bought the bike with 1,200 miles from the original owner, I bought from my dad 2 years ago with 29,000 miles on it and it now has 44,500 miles. took it home from the recall (about 20 miles) with no issues. Rode it 5 miles for an inspection and rear tire, no issues. Picked it up from there and the front brake lever went all the way to the bar with no front brakes. Pumped it up and it worked for the 5 mile return trip. backed it out of the garage yesterday for the 45 mile ride to work to only find out I ad no front brakes again. Pumped it up, again, and left for work. Figured I would call the dealer that did the service and get it in for a bleed because it was on the way home. They got me in and 20 minutes later, told me that my ABS module is now bad. He said mine is the 6th bike this week that this has happened to after the flush. Only difference being, my lever is not hard like everybody else has described. He then went on to tell me that because the manual tells you to flush the brake fluid every 2 yrs that Harley is not backing the price for the repair even though it was their recall and their flush that has caused the issues. My bike has never had one issue with the brakes and as you can see by the mileage, it is a bike that is ridden quite often. He said the new part is $375 and about 2 hours of labor. So I’m easily looking at over $500. I’m assuming, the only way the repair would be covered if the flush has been done by a dealership at the proper intervals and not by your own mechanic. I can’t afford the repair at the moment so just rode it home and parked it. I also told him, had they told me what the possible result from the flush would have been, they wouldn’t have touched it. He said that whoever has had this same issue needs to call customer support and complain. I know it’s the dealer, I’ve these guys and the owner personally for many years. hay are just as frustrated as we are.

    • David Sharpe

      Yes, you can bypass the ABS by installing standard brake lines from the master cylinders to the brake calipers.

  15. Frank

    I’ve the same problem although my Abs lights on
    Codes c1025 c1032 c1206
    Part no displayed 32836-09
    Had it at dealers who check ped front wheel issues
    They told it’s the module at fault ??
    Needs replacing
    2009 CVO ultra……no problem with breaking just the
    Light on….haven’t tried abs just in case it doesn’t work

    • Jake

      This is my LAST hd!! The big problem IS NOT being addressed by NHTSA. HD falsely advertised their abs as a fail-safe abs system. HD advertised their abs system will resume to normal, non-abs, braking if an abs failure occurs. We now know this is BS and not being discussed or researched. Instead, HD is blaming owners and NHTSA is disgracefully compliant.

  16. Cyril

    Hi to everyone.
    I have my front brake that collaps Last week on my 2017 FLSTF with 4000km on it! The front brake stops completly and was spongy. NO brake on the road! Scaring. I thought about air in the pipés and read about thé recalling to chang Dot4 fluid. So I flushed my system and replaced with à New Dot4 fluid but nothing changed. When I pump on the lever after 5 or 6 times it comes back but has soon my front wheel turns it stop working!
    I live in Tahiti and for the moment no HD dealer Just a HD qualified technician who talk to me about thé ABS module failure! Until the shop opens….in few month, he told me to cheat the ABS system on the front wheel by installing a new fluid hose directly connected to the calipster. Does anyone heard about this problems before? Tks

    • Customer Service

      Hi Cyril. We have not heard of any ABS module or modulator issues on 2017 or 2018 models. Hopefully this can be covered under warranty for you.
      Your friend gave you good advice.
      Try bypassing the ABS module by running a direct line from the master cylinder to the caliper. We have no idea what your front brake lever will feel like, but it’s worth trying. Your ABS light will stay illuminated until the correct repair is made by the dealership.

  17. Barry Valosin

    I just got a used 2015 Street Bob and the ABS isn’t working correctly at the front wheel. it has almost dumped me a couple of times because it isn’t actuating fast enough while I apply them slowing down to come to a full stop. I’m an auto tech over 30 years now and never experienced such a poorly designed system made by an American Company! Is there a way to disable the front wheel ABS while keeping the rear wheel functioning?

  18. Stephen

    Do you still have the old ABS unit in your possession? If you do, would you be willing to sell it to me. I would like to cut it open and examine the HCU. Thanks.

  19. Darrell

    My rear brake got real hard and wouldn’t work on my 2012 ultra classic, I press the brake pedal real hard and can get it to release and it works fine until I shut the bike off and restart it. So I pulled the fuse for the abs module and the brakes work fine without issue until I can get around to getting raped at the dealer.

  20. Robert Marioni

    Riding my 2012 Street Glide and a car cut into traffic in front of me. Both brakes were rock hard and I couldn’t stop. I jumped the curb and rode into a small grassy hill where the bike rolled to a stop then backed onto me and fell on me. I hurt my knee but it’s three weeks later and I’m ok now. Went to three Harley dealer and receive ZERO sympathy about nearly getting killed. I was quoted $1000, $800 and $800. I had a maintenance contract with Harley Finance and all my services were done. Brake fluid changed twice. I was a loyal Harley customer since October 1978 when I bought my first Harley. a 1979 Low Rider. Screw Harley service. My good friend is a good bike wrench but doesn’t have the software needed. We are going to replace the HCU (ABS Modulator) and front and rear brake lines. I will then tow the bike to Harley and pay them to replace the fluid and bleed the brakes using their computer. It’s the least amount of money to Harley. I will then put the bike up for sale or trade it in for an Indian.

    • Bob Marioni

      I ended up taking it to a shop and had the ABS bypassed. The brakes work great and I just rely on my experience to avoid locking them up. I kept the bike because I love it and I’m 63 years old and this will most likely be my last bike. I just put 14″ apes on it and I have fallen in love with it again. I may replace the ABS module one day.

  21. Robert Turnage

    First – Does the ABS Brake problem affect the rear brakes ? Is it safe to ride with the rear brakes working only or will the rear brakes fail?
    Second – I had my Harley Dealer ,Mike Bruno’s Harley Davidsin in Slidell LA., handle ALL of my maintenance , which they were to keep all of the service up to date. I even bought the VIP Service Plan. Now that my front brakes do not work it is my problem and expense to repair the ABS Brake System because the brake fluid that was required caused the ABS Brakes to fail. This is total bullcrap. Harley Davidson should repair these bikes at ZERO charge to the owner. I have had it with Harley Davidson , Does anyone know of a Touring Bike by a different company ?
    I have had several issues with my 2008 Ultra Classic such as Loosing power while riding down the Interstate , it does not kill but it loose all power , I have to pull over ,kill the bike and restart it and hope that it stays running with power. My Stereo system works when it wants . After one of the service the Dealer sent me home with a stripped out oil pan drain plug with the bike leaking oil. As soon as I got home I see the bike leaking oil , what kind of Master Mechanic (HA HA) does that kind of work .
    I am extremely disappointed with Harley Davidson and my Dealership . I have had other issues with the Bike and the VIP Service from Mike Bruno’s Northshore Harley Davidson. I have ridden Harleys all my Life BUT if the ABS Brakes are not fixed by Harley or the Dealership I am Through with Harley. Harley Davidson and my Dealership should have Do-Right and take care of this

  22. Kevin

    Harley-Davidson should replace the ABS module for free so we don’t get killed. If they don’t then I will move to Indian motorcycles in the future.

  23. Fabian

    Yes i have the same problem. The rear brake of my vrod stop working all of the sudden. I called harley Davidson and told me the abs system has to be replaced and it will be over $1,400.00 very disappointed because as is stated there are tons of vehicles with abs system and DOES NOT HAVE THIS KIND OF PROBLEM. It is very convenient for the harley Davidson that is a problem that happens for not doing the flush of the brake lines at the dealer with a technician. Very “convenient”. They should take ownership on these units defective and of poor quality.

  24. Walter

    Yeah, thanks for the article. I haven’t ridden for at least 6 months due to an injury but have cranked my bike a few times and noticed the right front break lever will not work. Rock hard frozen. I try to do all my work when it comes to replacing a part but now with what you mentioned above (software) I will be at the mercy of HD. Is there any way of doing this myself with out software? And your right! HD should do break fluid replacement and flush free until they fix this modulator. Seems a bit fraudulent that they know the problem, refuse to provide a replacement part, and hold us to paying them for something over and over again for something they designed to fail! Crazy. And with their rising labor rates its worst!!

  25. Robert Turnage

    Has Harley Davidson decided to have Do-Right and replace the bad ABS Modules on failed ABS Brake systems. There is an obvious problem with the design to allow moisture into the ABS Brake System .
    It is past time for Harley Davidson to accept responsibility and repair/replace damaged ABS Brake Systems. I paid to much money for the Motorcycle, additional upgrades and service for Harley Davidson to put the expense of the repair on us the owners.
    Harley Davidson , Either repair my 2008 Harley Davidson Ultra Classic damaged ABS Brakes or I will never purchase another Harley Davidson Motorcycle.I am a loyal Harley customer but not if it is a one way street, I feel as though I am getting screwed over.

  26. Turbo Seger

    I have a 2009 ultra classic I was riding down the road and my rear brake pedal would not go down it is locked into the up position and will not go down could this be part of the recall on the brakes that Harley issued for this bike?

  27. Brian J Gordon

    So I went to Brian’s HD do to the recall for the ABS issue’s. So they said they bleed the brake lines, I took my 08 touring CVO back home put in the garage and the next day went on a toy run with my son on the back and the front brakes didn’t feel right after getting back home I put the bike in the garage because how could it is now and it’s winter time so my bike sat in the garage for a while the one nice day I tried to back my bike out of the garage and I have no brakes my front brake line was hard as a rock I now have my bike at another shop fixing the problem the mechanic stated he didn’t think the mechanic from Brian’s Harley-Davidson totally flush the system out and particles remain in the ABS system causing it to break down but of course the dealership will not take fault. What are your thoughts thank you. I had no issues before.

    • jim

      Brian, Brians Harley Davidson like many other Stealerships SUCK ! I have had several issues with Brians In peticular. I have been charged for things that where never done. Recently bought a bike from someone who had Brians do service and winter storage. When i went over the bike, none of the service or maintenance had been performed that previous owner was charged for. I stopped going here for service YEARS ago and i was hesitent on even buying a bike that was bought or serviced there.Have not had any ABS Issues yet (knock on wood). But if i do, i will bypass the ABS and run new lines from the master cylinders. HD Should be accountable for making faulty products. Seems like they stop making decent stuff for over a decade now. SMH.

  28. Darron

    I think I have this problem. My front brake lever is hard as a rock and does not move when I squeeze it. I’ve check the master cylinder hardware by loosing the banjo fitting at the master cylinder while squeezing the brake and it moves and fluid comes out. I did the same test by loosing the line at the ABS module and the same thing, but nothing comes out of the return line at the Abs module leading to the front brakes. I’m guessing the clog or stoppage is within the ABS module. Can this be taken apart or rebuilt to clear the clog/stoppage?

  29. Ricky Loureiro

    Dear fellows,
    I am a brazilian and my bike was bouth in Rio de Janeiro, 2010, despeite it is a 2009 model FLRHC Road King Classic. I have moved with my familiy to Portugal and we carry our bike with us. I have stop the bike for moving procedures in April 2018 and i have naver received any email or letter from HD in Brazil – except for marketing purposes – talking about this issue.

    This year, in january 2019, I restart my bike from a long sleeping time and: SURPRISE. My ABS system has fail and the HD in Lisbon tells me to pay 1500€ (almost US$ 1700) to change it!!

    I am very angry and disappointed with this situation and I think HD should take care of it for the reasons you tell on your post and other.

    If you can help me with contacts, any solution or other ideas, please, let me know.
    I really need help.

    Many thanks,
    Lisbon Aug, 1st 2019.

  30. Dennis Holbrook

    Had recall done no problems before next morning brake pedal like a rock!! Now they say I need a new modulator and computer because good ole H-D discontinued 08 modulators and I have to upgrade to 09 WOW HOW CONVENIENT!

  31. Brian

    I have a 2010 FLHP and I went to ride and the front break is solid as a rock. I called dealer for the recall and was informed it would cosy over $700. This is crazy !! …. I have services my bike regularly and have only 11,000 miles on it. If I had known of the issue I would have had it checked during the service. This is a faulty part issue. It is sad that someone will have to die before Harley will address the issue.

  32. Kirk sanders

    Just recently purchased 2009 FLHX from a friend of mine because he not able to ride . He had a recall that he had received to flush brake fluid said he was unable to take care of it for medical reasons.So I called my local dealer made appointment to have recall taken care off .While recall was performed abs module locked up and I was informed it was going to be a 1000.00 to fix really on there recall I have to pay to replace there defective part .Cant understand why Harley Davidson not taking care of defective product leaving it to the consumer.Not good.

  33. Jeff Bates

    I have a 2010 ultra classic limited, at this time it has no rear brakes the brake peddle will not move. I located the problem it is the ABS system. I contacted my local dealer they advised they would change the fluid due to a recall. That will not fix the problem, is there anywhere to get a ABS system repaired or is a rebuild kit available ?

    • Customer Service

      Hi there Jeff!

      That’s a great question!

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  34. MadD

    I swapped my front ABS Master Cylinder from a DOT4 to 5 and stupidly flushed and replaced with DOT5. Does the ABS unit separate the front and rear fluids, so I can flush only the front and swap back to DOT4? Or do they cross contaminate?

    • Customer Service


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