ABS

[Borsig]

Hi Guys, I am Mark and I'm new to this social media thing, it has just taken 20 minutes to work out how to post a topic.  Tthis is the first social media group I ever joined so bear with me.

I have a 2012 Stelvio and need some advice about ABS, I am hoping there is someone out there who may have had similar problems.  I am not new to bikes and have been riding since 1975, I have owned at least 40 bikes over the years, including at least 8 Guzzis but this is the first bike with ABS and its got me stumped.  I spent 25 years as a bike mechanic and I specialsed in Italian bikes, but that was before all the modern electronics got piled on.  I like to think I can get myself out of any problems and I usually can but this one is a puzzler.

After owning the Stelvio for about 5 years the front brake suddenly started pulling in an extra inch towards the handlebar, it still worked as usual but had this extra travel.  The book says that ABS will not affect normal brake operations unless activated, which it wasn't as far as I know.  I stopped and tried various pumping actions at the lever and everything went back to normal.  It did it again a few days later, and again, and again.  Sometimes it would do it the next day, somtimes I would get a week or more between bouts.  I checked the fluid level, stripped and cleaned the pads and everything seemed good but it still carried on doing it.  It only ever did it once in a day and at no time did the ABS light show activation.

A car mechanic friend suggested that it was more likely a problem with the master cylinder.  Since a rebuild kit is not an option, I bought a used one from a Norge, same item, different coloured lever.  About a month later, just when I thought it was cured, it did it again, and again.  I then tried disabling the ABS every time I went out and over the next 5 weeks riding had no issues at all.  At some point I forgot to disable it and realised a few days later that the ABS had been on for a while and still no problems, so I carried on.  It lasted about 5 months until I hit some ice a week ago, the ABS activated and I had a long pull lever again.  This time no amount of pumping helped, I forced out the pads and pumped it up again, several times and I still have a long lever.

I have run out of ideas now, changing the fluid would be pointless unless I go to a dealer and get them to do it with their computer plugged in, as manually you can't change the fluid in the ABS parts, only in the normal pipes.  In all this time I have had no errors in the error log, no ABS warnings when braking, other than the ice incident and the rear brake is unaffected.  Is it possible that the system was not bled correctly when new and there is some air in the ABS which is released now and then?  Do ABS units give problems as they are quite complex with their solenoid valves and pumps?  Do I really have to take it to a dealer and trust some oik I don't know to repair my bike?  I do have trust issues on anything I haven't done personally and have been let down several times in the past.

I would be grateful for any help as I am stuck now.  Sorry to go on for so long but it needs explaining fully as its not a normal issue.

As an aside to this, has anyone had exploding spotlight bulbs on a Stelvio?  I was getting through one every 2 months or so and it usually takes the lighting fuse with it.

Mark

[greer]

Hi Mark, welcome to the forum!  There'll be some folks along shortly to actually help you with your bike, never fear.  Where are you located?  Might be someone close enough to lend a hand.

Sarah

[Stevex]

The only bike I have with ABS is a Honda CB1300 and I've just replaced the oem hoses with braided.
Bleeding the brakes was as per a non ABS system and I had no problems.
I'm surprised you say you can't do the same without plugging into a computer; I can't see how there would be a separate, unconnected brake fluid system.

[80CX100]

The pumping up and regaining pressure sounds like some sort of bleeding issue to me.

I know there's lot's of places for sticky air bubbles to get stuck, probably even more so in an ABS system, that's all I've got fwiw

good luck

[Perazzimx14]

ABS and non-ABS fundamentally are the same do not let ABS overwhelm you. The bleed procedure is the same and the lines can age and fail the same, If you have to pump the lever to pressurize the system and fluid is not leaking anywhere either a brake line is compromised or the master cylinder is tits up.

If the Stelvio has rubber brake lines replace them with braided stainless lines. The feel will be better and braided lines last a long time.

[Kev m]

I'm with those who are thinking this might still be a bleed problem.

Yes some ABS systems can be bleed thoroughly without running the modulator, but yes some cannot (or at least on some the OEM suggests doing so to be sure).

I don't know if Guzzi advises this on the Stelvio. One DIY method is to bleed, test ride (which actuates the modulator when it initializes), then bleed again. Repeat until you think you've got it. It's no guarantee but potentially saves you giving it to someone you do not trust.

[Perazzimx14]

To activate the ABS pump feet down, 1st gear and maybe 5 or 10 mph on wet grass or gravel road.....apply the brakes.

[Kev m]

To activate the ABS pump feet down, 1st gear and maybe 5 or 10 mph on wet grass or gravel road.....apply the brakes.

I wonder if you could get it to work on the lift with the wheel roller in place? Maybe not because the front wouldn't be moving or maybe that would help because it would freak out because of the difference in wheel spin. Would hate for it to go wrong though.

[egschade]

Warped rotor(s) pushing the pads back and creating extra lever take-up? Could also be the rotors are good but not moving on the bobbins freely causing the same problem.

[Perazzimx14]

I wonder if you could get it to work on the lift with the wheel roller in place? Maybe not because the front wouldn't be moving or maybe that would help because it would freak out because of the difference in wheel spin. Would hate for it to go wrong though.

Even the wet grass or gravel option is not w/o potential for it to go sideways. Extreme caution needs to be exercised if doing it this way.

The wheel roller may work but it would only activate the rear circuit.

[lucian]

Welcome Mark, like Kev mentioned sounds like air in the system, although the ABS system does a system check on startup it doesn't actually move fluid and thus air out of the pump. The brakes and ABS would have to be activated for that to happen. Any sensor fault with the system would result in the yellow abs light on the dash staying lit so I doubt it.s a system control issue, likely air or a pump issue.  You can bleed the system as usual but you will need to turn on the abs and take to a dirt road and at slow speed lock the rear brake hard enough to enact the abs pump.If you feel the brake let go and modulate the pump is working. Repeat a few times and then bleed the brakes again as normal. You may need to repeat the process a couple of times to ensure all the air is ejected from the abs pump.  Also when you park the bike for the night wrap a bungee around the front and rear brake levers to keep the system under pressure. It will help to squeeze the air out and let it  rise up to the master cylinders.  The abs pumps seldom if ever get activated and the pistons can get gummed up. The best method to avoid it is to manually activate them on occasion. There are outfits that will rebuild the pumps for cheaper than a replacement.  The BMW forums will have lots of info on them.  Best of luck .

[Kev m]

Welcome Mark, like Kev mentioned sounds like air in the system, although the ABS system does a system check on startup it doesn't actually move fluid and thus air out of the pump. The brakes and ABS would have to be activated for that to happen.

Are we sure of this? I thought the modulator quickly cycled all the pumps as part of the quick check on most systems? But I could be wrong.

[Don G]

I have an 09 Norge that the rear brake develops the same problem as the OP describes , all that can be done is hang a weight on the pedal over night and in the morning it works as its supposed to. Perhaps try pulling your front brake lever in and securing it overnight with a bungie or ty-rap and see if this cures it.  DonG

[Perazzimx14]

I wonder why motorcycles ABS are so susceptible to gumming up if not flushed every 2 years ? For example I have never flushed the brake fluid on any of my personal automobiles. My Tacoma was 17 years old when I sold it and the ABS/brakes functioned fine. I've had other vehicles with well over 100K on them and 4 or 5 years old that were never flushed??

For the record the ABS pump is no different on some automobiles than on motorcycles. The 2012+ Ford Festiva ABS unit is almost identical to the 2007 R1200GS ABS unit.   

[Borsig]

Thanks for all the suggestions, here is a response to most of them - the brake rotors are not warped, the hoses are braided and when the brake works, the feel is solid.  The inside of the ABS unit is sealed off from the main pipe unless activated, this was why I wonderred if there may be a little air trapped in it.  I replaced the master cylinder with a used one which was exactly the same, when this occurs it is always the same amount of extra travel, worn seals in the master cylinder tend to be erratic and can often be pinpointed by very slowly puling the brake as the seals don't expand and the fluid poasses, a quick pull and it works normally.

I am intending to change the fluid which I can do without disturbing the ABS by pumping fresh in as the old comes out, I will do it next week and put new pads in at the same time.  I have just wrapped a bungee around the lever, I've not heard that one before but I'll give it a shot.  I know that the ABS can be activated at will by choosing wet or loose surfaces but its a bit hairy doing that.  I have friends that live on a boat and the track leading to it is nasty enough to work, to get back I have to disable the traction control or I get stuck halfway.

Thanks again, I will report back on progress.
Mark

[Moparnut72]

I tested the ABS on a Harley I owned a couple of years ago. It was easy for the rear, but for the front I had to build up my intestinal fortitude to attempt to lock the front wheel. I was pleasantly surprised in that it was ultimately no big deal. Harley ABS systems need to be bled every two years. Has to be done with special equipment generally only available at the dealerships. I believe some of the bigger independent shops can do it. My small indy down the street says he can do it. He also says humidity has a lot to do with it. It isn't required as often in low humidity locales.
kk

[Huzo]

I have an 09 Norge that the rear brake develops the same problem as the OP describes , all that can be done is hang a weight on the pedal over night and in the morning it works as its supposed to. Perhaps try pulling your front brake lever in and securing it overnight with a bungie or ty-rap and see if this cures it.  DonG

I have not had that with my ‘07 Norge.
While performing the trick you mention may well work, it is only masking the real issue.

[Kev m]

I tested the ABS on a Harley I owned a couple of years ago. It was easy for the rear, but for the front I had to build up my intestinal fortitude to attempt to lock the front wheel. I was pleasantly surprised in that it was ultimately no big deal. Harley ABS systems need to be bled every two years. Has to be done with special equipment generally only available at the dealerships. I believe some of the bigger independent shops can do it. My small indy down the street says he can do it. He also says humidity has a lot to do with it. It isn't required as often in low humidity locales.
kk

"Has to" is a matter of potential disagreement (like you said, ambient conditions matter).

And there's an aftermarket tool to run the ABS, but it's not cheap (probably why the bigger shops you've found can and smaller can't).

[Borsig]

I tried leaving it overnight with the lever bungeed to the grip and it made no difference, I must admit I hadn't heard of that after 25 years as a mechanic so I was a bit sceptical.  Just ordered a litre of fluid to change both brakes, the clutch has been a bit variable lately so I'll do that as well.  Deliberately locking the front brake is not too bad so long as you are prepared for it and going in a straight line and upright, the ice incident I had a few days ago was not upright and not straight but I corrected and coasted to a halt with my front wheel against a parked car, it was only at around 15mph so I didn't need to change my pants afterwards.

What is the tool available to activate the ABS, I have looked but I am obviously not searching with the right words.  It might be worth it as my mechanic friend does bikes and might go halves with me.

I also mentioned exploding spotlight bulbs, I got through about 4 in the first year and stopped replacing them.  The headlights are insulated from vibration in the fairing mount but the spots are bolted to the engine bars and get the full force of the engine vibes.  My solution was to throw out the spotlight innards and silicone in 2 12v LED GU10 bulbs.  I had no idea if they would work out as all sources say that they work from about 10v to 13.6v and the Guzzi gets higher than that on a run.  It turns out that to get 9w bulbs I had to buy dimmable ones which I think are more tolerant of voltage variations.  They work really well, take very little power and are still going after at least 6 years.

[Guzzi Gal]

I’m chiming in just to add my welcome. As you’ve already noticed, we’re a friendly and helpful bunch. Don’t be a stranger once your bike is sorted, visit and post pics. Often!

[Kev m]

What is the tool available to activate the ABS, I have looked but I am obviously not searching with the right words.  It might be worth it as my mechanic friend does bikes and might go halves with me.

Sorry, no. I was talking about an aftermarket scan tool for Harleys.

Though it makes me wonder if GuzziDiag could be made to perform it.

[lucian]

I have read that the Bosch / conti scan tool will work on the abs function ,you will need the three pin  can bus adapter. For under one hundred bucks it would be worth it for this function alone. I have not used one personally . I change the fluid annually on the two bikes I have with abs, ( Aprilia Tuono  and a 1400 MG)  After replacing and bleeding the fluid I lock both front and rear brakes at 10 to 15 mph on a dirt road to activate and test the abs. No drama , if the system is functioning the bike will not lock up and skid. Everyone with or without abs should practices panic stops occasionally .  Repeat a couple times and then re bleed the system when you get back home. The problem with this method is that very little fluid is actually  moved through the abs unit. It  basically is pushed out and then drawn back in when the solenoid valves open and close. By repeated activation of the abs pump the stale fluid within the valves eventually gets diluted with fresh fluid from the inlet side if you continue to bleed off fluid from the caliper side. 

[Borsig]

Its worth a try when my fluid arrives, I'll just go carefully until then.

I notice that a lot of you have some blurb about the bikes you have owned bottom left of all posts, how do you add this?  There won't be room for all the bikes I have owned but I could just add the Guzzi highlights.

[Kev m]

Its worth a try when my fluid arrives, I'll just go carefully until then.

I notice that a lot of you have some blurb about the bikes you have owned bottom left of all posts, how do you add this?  There won't be room for all the bikes I have owned but I could just add the Guzzi highlights.

I think most of us just post the current ones.

But either way it's the signature field in your user profile.

[Bulldog9]

ABS Systems can be a pain to flush and bleed, especially if you are trying to flush old gunk out. Here is a tactic I have used.

1. Fush and bleed as normal. I use a vacuum bleeder that pulls through the open bleeder. I keep topping off MC till the brake fluid is clean running into the catch bottle. The old pump the lever method works too, but bleeders are cheap ($25).
2. Close bleeder and then pump lever, bleed any bubbles, etc as normal.
3. Go out, find gravel/dirt roads and repeatedly engage the circuit, getting the ABS plungers to spin, etc. This will help flush new clean fluid into the ABS unit.

I'll do this 2-3 times. Usually the first will show some darkening from the loosened spooge, by third round, is relatively clean. YMMV.

[Bulldog9]

I have read that the Bosch / conti scan tool will work on the abs function ,you will need the three pin  can bus adapter. For under one hundred bucks it would be worth it for this function alone. I have not used one personally . I change the fluid annually on the two bikes I have with abs, ( Aprilia Tuono  and a 1400 MG)  After replacing and bleeding the fluid I lock both front and rear brakes at 10 to 15 mph on a dirt road to activate and test the abs. No drama , if the system is functioning the bike will not lock up and skid. Everyone with or without abs should practices panic stops occasionally .  Repeat a couple times and then re bleed the system when you get back home. The problem with this method is that very little fluid is actually  moved through the abs unit. It  basically is pushed out and then drawn back in when the solenoid valves open and close. By repeated activation of the abs pump the stale fluid within the valves eventually gets diluted with fresh fluid from the inlet side if you continue to bleed off fluid from the caliper side.

Annually? man now I feel Lazy doing it every 2-3 years... I use (just posted) the same method to clean out the ABS pump. Works a trick.

[lucian]

Annually? man now I feel Lazy doing it every 2-3 years... I use (just posted) the same method to clean out the ABS pump. Works a trick.

  Not much else to do up here in the winter months besides consume fluids of all types. 

[Borsig]

Ordered some fluid yesterday which will be here during the week but I have had weeping fork seals for the last 2 months or so, got the replacements but have been too busy with work to fit them.  As the left one got really bad 2 days ago I should combine fork seals, pads and brake fluid in one mammoth session, the customers will have to wait another day.

Just for interest I have had quite a few electrical glitches over the years, the exploding spotlight bulbs, the key code reader stopped working, the lights went out (on an unlit road of course) and corroded connections.  My Stelvio was the 8 valve version, not the NTX, I wanted the fitted panniers, not the camera boxes that the NTX came with, and they came with the bike.  I bought the engine bars, spotlights and hand covers later and about 2 weeks into ownership I got caught in a downpour, the 25 yards visibility type.  I noticed that the high beam warning light was flickering, as I was following a van close enough to see but far enough away to stop, I saw that it was high beam flasking on and off.  As I got wetter the light stayed on more and I did the last 15 miles with both high and low beams on.  A check when I got home showed several cc of water in the switch cluster, a hairdryer and WD40 cured it forever.  The cables on the left of the tank coroded, lack of protection, WD40 fixed it again.  The key reader has a very stiff cable that snapped the wires at the reader end as they couldn't take the turning of the bars, fixed by removing some plastic around the wires an soldering longer fleixible wires in.

The best was the lights, just hi and lo, I still had side lights.  I carried on to where I was going and looked at the fuses but nothing there, so I followed a friend back to the city lights to get home.  The wiring diagram of a modern Guzzi is scary, a quick look didn't show up anything likely to be a problem so I went through all the fuses, relays and checked all the connections.  Running a jump wire from the battery to the lights feed wire got them working, but permanantly, so I had to leave a link I could unplug.  I printed off the wiring chart on 2 sheets of A4 and traced the wires in the lighting circuit then tried to track the wires on the bike and test them at various points.  It turned out to be a broken wire in the loom that feeds 2 of the relays, it still fed one but not the other.  The fix was a bridging wire between the relay terminals as taking the loom apart is never a good idea as I had no idea where the actual link was between the 2 wires.

I would have thought that greasing connectors and switches would be a good idea on any bike when assembled in the factory, they get a lot of rain in Italy but leave it to the riders to sort out.  I also thought that things had improved wiring wise over the years, but obvoiusly not.  On the old 80s Guzzis, of which I had 5, I used to throw away the original naff switches and replace them with after market Suzuki ones with the mass of wiring plugged into the back of the headlight reouted to connect up under the tank.  Much more reliable as the old switches would regularly melt.

[Borsig]

OK, next installment

I rebuilt the forks yesterday with new seals, cleaned the calipers while they were off but didn't replace the pads as they still have a fair way to go.  I left the calipers off and forced the pistons back and wedged a piece of wood in each caliper.  This ensures that most of the fluid is now in the pipe or reservoir, then I pumpud about 200cc of fresh fluid through until it was running clean.  It was all reassembled and tested and nothing has changed, I still have a long front brake, not what I was hoping for.  I went out for a ride to bed things in and look for a gravel/rough road to activate the front ABS a few times and despite riding round for 15 minutes, I couldn't find anything suitable, all the off road bits have barriers and all the accesible bits have tarmac.  The brake didn't change, still long although it still works well when it bites.

This is becoming a real pain.  Friends live on a boat and they have a gravel carpark so I might pop down there to do a few front wheel slides, and I had better take some tools in case I need to bleed things again.  If that produces no results i will book it in with the nearest dealer, about 35 miles away, if they are open as we are in lockdown here.

Mark

[Borsig]

A week on since new fluid, I have managed to activate the ABS several times and it has activated on its own a few times.  I have bled it through twice more and forced the pads into the calipers and re pumped the brake at least 4 times, still no improvement.  What worries me most is that the ABS has activated under gentle braking in the dry on tarmac roads twice now, with no obvious reason.  Has anyone had this before?  A friend sold his Kia car for a similar reason, it would activate quite often when stopping at junctions under moderate braking but he never found the problem.  My dealer says he is willing to bleed the brakes with Navigator connected but says that it is unlikely to fix the problem as air should never get in the ABS without serious dismantling, which has not happened, he suggests that the ABS unit might be faulty (as in an internal leak) and this also will not show up during tests.  He won't even give me a price without doing the job first.

The only thing I haven't done is replace the pads, which I will do today just to eliminate them from the equation.  Here's a question, does anyone know what might happen if I reroute the front brake to bypass the ABS unit?  I can have a new hose made to connect the master cylinder directly to the front splitter on the lower yoke, the brake will then not be connected at all to the ABS.  The ABS does not react to pressure in the pipes and is triggered by the sensors, will it know that the hoses have been rerouted?  When setting off, the computer will still receive signals from the sensors and will think all is normal, obviously there may be some leakage from the ABS unit if it activates but that can be soaked up by a rag tied round the connections and the rear brake is a separate system and should not be affected at all.  Any thoughts and has anyone tried this?

Its been over 3 weeks now with a shit front brake and the bike is only suitable for local runs, I can't trust it at speed or for any distance, desperation is setting in here and any more suggestions would be good.  The bypass option is looking better by the day.

Mark