I loosen the bleeder screw, then with a C-clamp push the piston back into the caliper. This way I'm not forcing old fluid back into the ABS.
sevicing disk brakes with ABS?
- Thread starter cousincletus
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I haven't had any problems from just pushing the piston back.
ABS system is basically "closed" when it's not in-use anyway. Fluid will be pushed back into the master cylinder if the bleeder screw is closed.
Keep in mind rear disc brakes usually need a special tool to "turn" the piston back into the bore so it dosen't ruin the parking brake mechanisms.
Keep in mind rear disc brakes usually need a special tool to "turn" the piston back into the bore so it dosen't ruin the parking brake mechanisms.
A 3rd for cracking open the bleeder. I do not want dirty/water laden fluid being pushed back anywhere in the vicinity of my expensive valve body. Fluid still has to go though the valve block even with the key off.
Unless you plan to frequently mess with the hydraulic system, don't open the bleeder on a reline job. If it sets until the next reline job with brake fluid in the threads, getting it loose without breaking it may exceed your skills.
I never touch mine until I decide it is time for preventative rebuilding of the caliper. Then it is slathered with Sil-Glyde insuring it comes loose the next time.
I never touch mine until I decide it is time for preventative rebuilding of the caliper. Then it is slathered with Sil-Glyde insuring it comes loose the next time.
do no under any circumstances clamp off brake hoses! it will collapse the internal structure/lining of the hose and you will have comprimised brakes!
I got bogged down on the bleed screw and left this important point to Chris. Amazing the disinformation on brakes.
Do i need to clamp the caliper hose before pushing the piston back in? If so how to do it and why?
Not in my experience on my GMs.
You'll need a tool that will let you "screw" the piston back in on the rears. They will not simply push back in. Believe me, I wasted a whole evening trying to figure that one out. Depending on the piston itself, you may be able to use a real wide flat screw driver and do the push and turn method to get the piston in. With Honda's, I would not loosen the bleeder valve, especially if you are doing it yourself. Bleeding the rears takes at least two people. Get the turkey baster out and suck out some of the brake fluid from the reservoir first, and then push the piston back in. At this point, before you put it all back together, suck out some more of the brake fluid with the turkey baster and replace it with new fluid since you got to re-add anyway. You won't get all new fluid, but you'll get quite a bit of new fluid in the brake system.
you can gravity bleed the brakes just fine. if theres no air in the system just gravity bleed it. its the easiest way to get new fluid in but maybe takes a lil longer.
Makes me glad I don't live in the rust belt (anymore) where I have to worry about snapping bleeder screws off. Forgot about that being a problem in some areas.
Ditto on loosening the bleeder valve on the caliper before compressing the piston. Some pistons compress with only a c-clamp, others need to be turned as they are pushed.
I bought a complete kit on sale for $10 at Harbor Freight that works great on the push and thread in type of calipers.
I bought a complete kit on sale for $10 at Harbor Freight that works great on the push and thread in type of calipers.
ChrisW writes:
They gave the tool number (J-blah blah blah) and it looks like a miniature wringer off an old-fashioned washing machine. In fact GM says to use this tool when servicing ABS -- clamp the hose and open the bleeder valve. I've seen plastic jawed pliers which were designed to do this too.
I'm not doubting your advice, ChrisW. But I just had to point out that there are always exceptions out there! It is probably wise to avoid clamping off a brake hose unless someone has a darn good reason to do it.
Actually, according to one of GM's recent training videos on hard to diagnose pulsation and noise concernts, it is perfectly OK to clamp off a brake hose provided that you use the correct tool. But GM says never use vise grips.
They gave the tool number (J-blah blah blah) and it looks like a miniature wringer off an old-fashioned washing machine. In fact GM says to use this tool when servicing ABS -- clamp the hose and open the bleeder valve. I've seen plastic jawed pliers which were designed to do this too.
I'm not doubting your advice, ChrisW. But I just had to point out that there are always exceptions out there! It is probably wise to avoid clamping off a brake hose unless someone has a darn good reason to do it.
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