2003 Chevy Avalanche. I want to change the brake fluid in my truck. Can I do this with a hand held vaccum tool then loosen the bleeder valve and suck the fluid out until I get new fluid or do I really need someone inside the truck to apply the brakes then loosen the bleeder valve to dump the old fluid. I’m not sure on these newer vechiles with ABS brakes. I don’t want to hurt the braking system.
I change brake fluid in 2 ABS vehicles. I just gravity feed each wheel one at a time and don’t let the master cylinder get too low. It is slow but I have lots of time. On one I can suck out most of the old fluid and the other I can’t so I just keep adding. I do this every 3 years, it is important on vehicles with ABS.
The vacuum pump may work but there’s no substitute for the old foot and you don’t need an assistant but it’d take less time that way. When I say the old foot I mean be gentle and don’t push the brake pedal much more than half way down each time. I did it on a '94 Plymouth Vogyager w/abs. Only had 2 drain pans so I started with the back; broke the bleeders free and started gently pumping the fluid out. MAKE
SURE THE FLUID IN THE MASTER CYL RESEVOIR DOESN’T GET NEAR THE BOTTOM. You might buy 3 quarts of brake fluid, keep reciept, and return any
unopened containers. If the bleeder screw(s) won’t unscrew heat bleeder screw w/propane torch just to cherry red. Immediately squirt water on bleeder screw. As soon as screw is cool enough to touch (while you’re squirting water), immediately turn it gently w/wrench. If NG, try again. You’ve gotta push fluid out till brake fluid coming out bleeder is same clor as new fluid. You don’t have to close bleeders
when you run up front to see if M/C is low. Took me an hour and a half. Fluid started out black but boy was it great to see that clear amber color! The internal parts of your brake system will say, “Thank you!” Maybe call the dealer first and ask to talk to foreman to be sure it won’t hurt ABS. I’ve never seen it happen.
I have bled brakes on a 1996 GM vehicle with ABS with no apparent problem. I prefer the two person method so that any debris that might be residing at the bottom of a wheel cylinder will more likely, due to turbulence, be stirred up and pumped out of the bleeder valve. Simply draining will get fresh fluid in but may not handle debris as mentioned if the bleeder valve is located at the top of the wheel cylinder.
A method to loosen stuck bleeder valves that may otherwise break off with steady applied torque is to use an impact wrench at a very low setting so that the wrench barely functions and increasing power as needed. Use a little penetrating oil, of course.