Anti-lock brakes question

[ycartf]

I have already looked in the Toyota guide info for a Gen 2, 3, and 4 and they only mention pressing the piston in with a hammer handle or water pump pliers (don't think I have ever seen those - I use C-clamps) and if it is too hard then loosen the bleeder screw. But I thought I saw where someone mentioned that if your car has anti-lock brakes you cannot just force the fluid back into the system when you compress the piston back into place, but that you have to bleed the fluid out through the bleeder screw.

Can I get a general concensus from those of you out there who know about the anti-lock brakes stipulation? This 1997 I4 Camry is the first car we have ever owned with ABS. Thanks in advance for all replies/help.

[ASG14]

I'm a little confused with your question. Are you changing the pads and need to push the piston back to get it over them?

[ycartf]

Yes.....when forcing piston back into caliper...........is it ok to force fluid back into the system or do you have to bleed it out through the bleeder screw?

[ASG14]

Well, I've done mine 3 times in the last year, and just force it back in, and never had an issue, and never heard of any issues with it. I have a '96 with dual front pistons and ABS.

[Chunger]

You *may* damage the ABS system by forcing any debris back into the module... safer to bleed the fluid out the bleeder valves when pushing back the caliper pistons. May be worth it to you to get those one-way bleeder valves but make sure you rebleed your whole system afterwards.

[toyomoho]

On ABS systems many brake repair experts now recommend releasing the bleed screw to relieve pressure and allow the pistons to retract. They state they have experienced problems caused by the old “C” clamp method, etc.

[ycartf]

Originally Posted by toyomoho

On ABS systems many brake repair experts now recommend releasing the bleed screw to relieve pressure and allow the pistons to retract. They state they have experienced problems caused by the old “C” clamp method, etc.

I have done many brake jobs over the past 20 years (but not on ABS) and I understand brake bleeding / have a brake bleeder. If I understand you correctly - you are saying that just releasing the screw will allow the piston to retract (not needing pressure like the C-clamp) or that I should use the C-clamp but with the pressure/fluid allowed to exit via the bleeder?

[Chunger]

No... if you just loosen the bleeder valve, fluid will just leak out (and air into the system)... you still need to mechanically push in the pistons. There is no "spring" that returns the piston to the "in" position, LOL. I don't think that even a pneumatic air bleeder will draw the pistons back in but I'll let toyomoho answer that.

[ycartf]

I thought there had to still be mechanical force applied to force the piston back in - but the way he had it worded I wanted to make sure - thanks for all replies. I will bleed the pressure through the bleeder screw when I force the pistons into the caliper on this one car we have with ABS.

[toyomoho]

Thanks for pointing out the ambiguity of my answer. Toyota appears to state that opening the bleed valve to move the piston is not necessary for their ABS system.

However, have heard that forcing fluid back into the ABS system can cause contamination and issues over time with ABS systems. As such many professional mechanics recommend opening the bleed valve to allow this fluid to run out of the system.

The pistons will of course need to be physically moved back to allow the new pads to fit. The can be done with a “C” clamp or some other tool.

[marc780]

Originally Posted by ASG14

Well, I've done mine 3 times in the last year, and just force it back in, and never had an issue, and never heard of any issues with it. I have a '96 with dual front pistons and ABS.

Same goes for my 2001 V6 solara - did the front brakes, just used the c-clamp to push the piston and change the pads. No problems afterwards with the brakes

[Mike Gerber]

I have done the brakes, both front and back, on my 94 with 4 wheel disks and antilock brakes, and my 98 with front disk and rear drums and antilock brakes, numerous times just pushing the pistons back in, and have had no problems.

Mike