Changing brake pads - damaging ABS. True?

neo_psy, Jun 12, 7:44am
Hey y'all,

About a million years ago, someone told me that replacing pads and discs in ABS-equipped vehicles is risky as there's the possibility of damaging the ABS system (I seem to think he said there was a sensor *in* the caliper that you can damage by pushing the piston back too far).

Any truth to this! Seems plausible enough, I guess.

thunderbolt, Jun 12, 7:46am
The sensor in generally pointed at the teeth on the CV joint behind the hub.

There is a chance you could give the sensor a decent knock as cause it to fail, but if respect the sensor, you should be OK.

supernova2, Jun 12, 8:58am
I read (so it must be right LOL)somewhere that the problem is pushing the fluid backwards through the ABS pump etc and that the safe way is to crack the bleed screw.Probably a good idea to let the fluid out as at least that way if you top up the master over about 20 pad changes you will have achieved a fluid change!

tigra, Jun 12, 9:10am
20 Pad changes!How many years is that!

bigfatmat1, Jun 12, 9:19am
The crap in the fluid is generated in the end of the line. so its a good idea. to crack the bleeders while pushing the piston back to prevent pushing this shit through the system. Chances are slim of that crap getting back through the system but if it does it can jam under the solenoids in the modulator creating sticking solenoids. Its just a preventive it pays to be careful rather than creating expensive problems.

supernova2, Jun 12, 10:55am
20 pad changes if you are that poor girl with the pug in the other thread is about 12 months.

kazbanz, Jun 12, 5:00pm
In life ANYTHINGis possible. Ive personally never encountered that problem
Then again ZIve never ridden a bike with 12psi in the rear tyre either.

paul861, Jun 12, 6:48pm
never been on a dirt bike! wont get far with much more 12 lb

kazbanz, Jun 13, 8:43pm
Paul -sorry bro its a private joke between Neo and me.Ya see there was this one time in band camp.

purple666, Jun 13, 10:27pm
12lb is about right for ridgeds

steve312, Jun 13, 10:40pm
There is definitely no sensor in the calipers of an ABS system.The wheel speed sensor is attached to the backing plate or suspension leg.As already mentioned, the concern is the crap in the hydraulic system getting forced back through the modulator block and master cylinder.It is no more risky forcing the fluid back to the master cylinder on an ABS than a non ABS brake system.The ABS side of the system is isolated from the normal braking hydraulics by solenoid valves and seals.If you have any concerns about the age and condition of the fluid (and most brake systems are not flushed as often as they should be) then I would recommend cracking a bleeder on each caliper as you force the piston back for pad replacement.

sr2, Jun 13, 11:13pm
+1, Good sound advice.

neo_psy, Jun 14, 8:49am
Aha - cheers all (even you, Kaz.)

Not actually an urgent query, as nothing needs new pads, but I was just curious.