Will anyone in the USA rebuild the ABS control module?

[RCinNC]

I would love to see a practical demonstration by an engineer of just how far hydraulic fluid (and any included sediment) moves in a closed hydraulic system when you apply pressure, as you do when pushing brake pistons back into the caliper. I've seen this explanation before, that when you push the pistons into the caliper, the debris inside the caliper gets pushed back up into the ABS module. There's got to be 16-18 inches between the caliper and the ABS module under the seat. Any debris in the caliper is obviously denser than the fluid surrounding is, or else it wouldn't sink to the bottom of the system. How much does the piston move when you compress it? Half an inch? How does that translate into debris moving something like 16-18 inches, against the force of gravity, through a fairly dense fluid?

Every time you compress the brake lever, the pistons move in and out. Not as far as when they're compressed by hand, but still, they move in and out constantly. How is it that this constant compressing of the system doesn't create this movement of debris, yet compressing the piston by hand sends this debris all the way up to the ABS unit?

I suspect that the ABS module is the reason you're not supposed to compress the brake pistons without opening the system first, but not because it sends debris up into the module. It seems like it might be more of a function of the valves in the unit, and that they aren't designed for pressure to be exerted in the opposite direction. Naturally, I don't know the answer, not being well versed in the fields of fluid dynamics and hydraulics, but I'd love to see this theory examined by an actual engineer.

 

[Kruzzin5]

Reviving this old thread as I was following it closely while the OP and others worked to fix their ABS issues.
My ’12 was purchased 18 mos ago with a glowing ABS light and codes for Front Sensor and Pump Motor.
Front Sensor replaced (that error code gone, TC working again) but the Pump Motor code remained as expected (fault code 33: Pump Motor/No Voltage).
I had gone through the Service Manual and checked just about everything I could regarding continuities, voltages etc and there had been no used ABS pump units on Ebay for a while…
Until a few weeks ago. I got an email notice for a new posting of a very reasonably priced 2013 pump so I bought it immediately and 2 days later it arrived.
Swapped it out, bled the system but no change, pump motor not cycling, AND, I still have same Error Code. Freaky coincidence?
More poking around, checking fuses again… hmmm, the 30A pump fuse looks good but is a rather loose fit in its receptacle so I fix that and then try to cycle the pump yet again.
The pump suddenly comes to life and whirrs away for ~5 seconds just like I’d seen on Youtube, something neither pump had done before.
A test ride confirmed all was working normally and the ABS light was off so I then re-installed my original pump unit and it also works normal, no codes etc.
I’m going to leave the original unit in place and keep the ebay unit as a back-up or possibly just sell it here on the forum.
So… NO voltage had been the issue all along due to a loose-fitting fuse.
Mr. BR

Note: regarding the OP’s question of “Will anyone in the USA rebuild the ABS control module?”. A place called Module Master in Moscow, Idaho USA was mentioned in one of the FB groups and looked promising based on their website. But after reaching out to them about the Super Tenere, their reply was “This is a motor type we do not work on. Sorry”.

Great diagnostics!

 

[WJBertrand]

To determine if debris in the caliper can reach the pump, one would have to do the comparative volumetric calculations using the ID bore and stroke of each caliper piston and the ID and length of the associated line(s).
I’ll bet the volume of all 8 front caliper bores, assuming one is installing new pads in both front calipers at the same time, and the old pads were well worn, (maximizing stroke) easily exceeds the volume of the line.

 

[Jlq1969]

I would love to see a practical demonstration by an engineer of just how far hydraulic fluid (and any included sediment) moves in a closed hydraulic system when you apply pressure, as you do when pushing brake pistons back into the caliper. I've seen this explanation before, that when you push the pistons into the caliper, the debris inside the caliper gets pushed back up into the ABS module. There's got to be 16-18 inches between the caliper and the ABS module under the seat. Any debris in the caliper is obviously denser than the fluid surrounding is, or else it wouldn't sink to the bottom of the system. How much does the piston move when you compress it? Half an inch? How does that translate into debris moving something like 16-18 inches, against the force of gravity, through a fairly dense fluid?

Every time you compress the brake lever, the pistons move in and out. Not as far as when they're compressed by hand, but still, they move in and out constantly. How is it that this constant compressing of the system doesn't create this movement of debris, yet compressing the piston by hand sends this debris all the way up to the ABS unit?

I suspect that the ABS module is the reason you're not supposed to compress the brake pistons without opening the system first, but not because it sends debris up into the module. It seems like it might be more of a function of the valves in the unit, and that they aren't designed for pressure to be exerted in the opposite direction. Naturally, I don't know the answer, not being well versed in the fields of fluid dynamics and hydraulics, but I'd love to see this theory examined by an actual engineer.

I'm not an engineer, but the distance between the caliper and the ABS wouldn't be important. The important thing would be the cubic capacity of the caliper vs the cubic capacity of that “distance”... It would also be important in the movement of fluids, the diameter of the master and slave cylinders (in the case of the caliper, when pushing the piston inward, This becomes a master, and since it is much larger in diameter than the pipe, the speed and pressure of the liquid (circulating in reverse) is much greater than the movement you exert to push it. But cubing (by eye), it would be more or less:.
.piston 5cm diameter x 2 cm stroke…(r2xpi)x height=39cm3 in the caliper……..
pipe to the abs (using your data 17 “=42cm) and assuming that the inside of the pipe is 5mm thick diameter…..
(r2xpi)x42cm….8cm3 in the pipe
but trust more in what WJ said
Regarding the valves inside the module, you are right, surely some valve is blocked and causes the rear brake to fail. Why?…I think no one knows.
We have assumed that the “incorrect processing” of changing the rear pads causes the failure, but for an obvious reason, the module fails after manipulating the rear pads (and it did not always happen after the first change of pads)..
How does the air come in to the rear circuit without loss of liquid?….it is also not known, only by “assumption” and assuming that a valve is blocked at 99.95%…”could” a normal phenomenon be occurring in hydraulic circuits under pressure… (the liquid under pressure, which tries to pass through a hole that is too small for the structural tension of the liquid 0.05%), its structure breaks, and any liquid whose structure breaks, tends to transform into a gas (bubbles)

 

[Jlq1969]

But there is another very particular characteristic of the failure…”the combined brake”.
If you search on the internet, you will see that many users of motorcycles with a combined brake (of any brand and model) complain about the failure of the rear brake. Which makes it “suppose” that in the case of ABS modules that serve as a pump for the combined brake, there is one (or more than one) valve that tends to block.
In cars I have not read reports of rear brake failure, but there is one obvious thing: the braking in cars is always “combined”, the ABS did not “act” as a pump to brake, the ABS only “pumped fluid” in emergency situations likr the TCS and ESP….I say “acted” and “pumped”, because that was before. Now. With adaptive cruise systems, and emergency brake system, the ABS “pumps” fluid to the calipers to brake…..

 

[Mr. BR]

@Mr. BR - An interesting outcome for sure. Of note is that it was a common farkle among some S10 riders to add a switch to the ABS circuit by tapping in at one of the ABS fuses in order to be able to disable ABS on the fly by cutting power to the ABS with a bar mounted switch. It was just a bit of wire, a fuse holder and a switch. (some used a relay as well, IIRC) Makes me wonder if some previous owner of your bike messed with that, then removed it later, causing the looseness in the fuse holder?

Hey Eric,
Good question and perhaps one of the previous owners did have an ABS ON/OFF setup as I do have an un-used rocker switch on the dash AND... it has a 30A rating. I was told the orignal owner had a long commute (put 70K+ miles on it) and perhaps he did do some off-roading where there ON/OFF was needed. Anyway, all is well for now and I'm happy to get the ABS functioning and no more glowing light on the dash.
Regards,
Mr. BR

 

[EricV]

I think you've found your smoking gun with that toggle switch. FYI, while you can just turn the ABS off by cutting power with the switch, (wired inline with the OEM fuse location), you can't turn it back on by just flipping the switch again. You have to flip the switch to power the circuit, then cycle the ignition by shutting down the bike, key off, key back on. Otherwise you just get the ABS warning light and no functioning ABS until you cycle the keyswitch.

 

[Checkswrecks]

I would love to see a practical demonstration by an engineer of just how far hydraulic fluid (and any included sediment) moves in a closed hydraulic system when you apply pressure, as you do when pushing brake pistons back into the caliper. ...

It's easy to calculate how debris in the piston cavity gets flushed up to the master cylinder when the lever is squeezed.

Motorcycle line = 4.75mm ID
Area = pi R2 = 29.85 mm2
Length 20" = 508 mm (This is way more than actual)
Volume in line 30mm2 x 510 mm = 1530 mm3

Piston roughly 30mm diameter
Area = pi R2 = 2827 mm2
Times 4(?) mm travel = 11,309 cubic mm
Times 2 pistons in rear = 22,618 cubic mm fluid movement
(Two for rear, eight for front)

So the rear line contains less than 7% of the fluid in the system.

Carbon, dirt, and anything else is going to collect at the lowest point - the caliper. Of course brake fluid is hygroscopic, meaning it traps and carries moisture which can collect at the lowest point - the caliper. This results in all the trapped crap and water being flushed through the ABS module when the brakes are used with some inevitably getting hung up in all the teeny things that make it function.

 

[SkunkWorks]

Mine only has a single-piston Rear Caliper........................