What the inside of a bad ABS unit looks like

Nikolajsen

"Keep it simple"
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Jul 1, 2017
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2,043
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Denmark
Well I test rode it today... and got mushy brakes :(
The ABS worked perfectly and UBS worked well for a while so a bit disappointing.
It could have been trapped air in the unit so I’ll give it one more try tomorrow.

Out of 5 electroplaters throughout NZ only one has replied saying he can’t promise anything but wants me to courier them for so he can have a closer look.
Damn:mad:. To all in this post.
Hope it is air:cool:
 

MikeinNZ

Active Member
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Sep 27, 2018
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120
Is the idea to have the electroplater build up the pistons slightly oversized and then have them ground or turned back to the correct diameter?
I’m also wondering if the replating route doesn’t turn out to be an option could those pistons be turned down in a lathe and sleeves made up to bring them back up to the correct outside diameter.
I think your idea of drilling and taping the four raised points where the motor was originally swagged on, and using a spacer block and retaining band to hold the motor back on would work fine. It wouldn’t need to be a very deep threaded hole to hold the bands down and work.
All of this work falls under the heading of experimental, but often good fixes and repairs come from it that may be helpful to others in the future. Let’s hope for some good news from the electroplater.
Correct on the electroplating. Hard or industrial chrome and then ground back to original.
Your right about experimental, both times I have had it apart now I put it back in the bike and hold my breath as I turn on the key.
The first and second cycles of the ABS pumped zero pressure back to the lines and I thought I’d wrecked it.
The following cycles all felt normal though..
I better get up and go for a ride.
 

MikeinNZ

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Sep 27, 2018
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Still mushy brakes ... rode it down to the post office to get the Pistons away to Auckland and spent the first money in trying to repair this thing.
I re-measured the 5.6mm drill shank I used and it is 0.2192” minus any polishing I did so probably 0.2190”.
The undamaged part of the piston measures 0.2208” so I am 0.0018” to small.
It doesn’t sound like much but my last hope is 0.8% less diameter is not helping the seals seal.
I have asked the electroplater to add 0.001” to the finished size to allow for wear so hopefully this can be done.
I’ve come this far so may as well see it through.
I have bypassed the ABS unit and bled it up. I’m going to take it to work tonight rain hail or shine and try to get my smile back.
 

2daMax

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Jun 3, 2015
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647
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Penang, Malaysia
If it is not trapped air, it could be a internal fluid leak within the rear ABS sector. Don't make sense for an external leak since a pressurized system will squirt out fluids rather than take in air. I saw a block diagram of how a ABS system works and there are a few check valves that may have not functioned and there is a reservoir that has a spring loaded plunger/piston. A leak at such a reservoir could be where the mushy feeling or if there are air trapped there, could also be the culprit. Just some thoughts. Hope you nail it.
 

MikeinNZ

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Sep 27, 2018
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Thanks for that, have asked if it’s still available but @ 162,000 miles :eek: that’s amazing!
 

gv550

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Sep 14, 2016
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849
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Listowel, Ontario, Canada
Thanks for that, have asked if it’s still available but @ 162,000 miles :eek: that’s amazing!
162k is a lot of miles for any motorcycle component, but just for reference the 2009 Kawasaki that I recently traded for a new Tracer GT had 425k miles on it still had the original Mitsubishi ABS unit and (gasp) original hoses and seals! It also has integrated braking with power boost and never gave any trouble, ridden hard and put away wet numerous times. However, I did replace and bleed the brakes and clutch fluids 4 times a year and even though the used fluid never looked that bad in the brakes they always performed noticeably better after the fluid change. The clutch fluid was always dirty even after only a few months.
 

MikeinNZ

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Sep 27, 2018
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Finally got a phone call from the electroplaters who quoted me $500 Nz to repair the 2 pistons. Seems when they know they are made from unobtainium the price goes up :(
Not worth spending that money so have shelved it for now.
In talks with Sallydog trying to buy the used one.
 

foosyerdoos

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Nov 19, 2014
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Aberdeen, Scotland

MikeinNZ

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Sep 27, 2018
Messages
120
Have you changed the clutch basket and cam chain tensioner ? I have a gen 2 2015 Es. I believe you are a gen 1. Some of the other guys who have been around a wile can verify, but I believe those are two things that should be addressed. They can create major problems. I would hate for you to go to all this trouble just to have your bike die from a foreseeable problem.
Judging from the vibes around 3000 rpm I would say the clutch basket is original and the cam chain tensioner is on my to do list.
 

Bigbore4

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Oct 20, 2010
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828
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Andover Minnesota USA
What sort of plating do the pistons need? There is a guy over on ADVR that restores vintage bikes. He has a home canned plating rig he does zinc plating with. Might be worth a look and conversation to see if what he is doing might help? User Name is Fast Idle. Currently building a '67 Bridgestone.
 

MikeinNZ

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Sep 27, 2018
Messages
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Update: one of the guys at work machined me up some new plungers with a ground finish last week. I fitted them 3 days ago and everything is working as it should. EA1C44B4-C8AF-4D01-8969-18D2B5C0B804.jpeg
The new one on the left obviously.
I have been happily riding it with both brakes bypassed but with winter around the corner I decided to give it another nudge.
Pretty stoked.
 

Mzee

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Mar 17, 2013
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Johannesburg
My S10 is first generation. Many years ago, I checked the ABS housing and found mud and some water there. I drilled one hole in the housing and that was really a wise thing to do then. This is consistent with MikeinZD's post. After reading this post, I went to check and found it dry, very dry like it has been baked in an oven.
 
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