So I'm going to be replacing brake pads soon on my 2000 Jimmy, and was reading what I could on here about it. I came across the posts that say to not let the brake fluid get pushed back into the master cylinder when compressing the pistons to make room for the new pads. I should instead attach a hose to the bleeder valve at the caliper and let the fluid drain there. My question is will air get into the system if I do it that way? Or if I place the hose in brake a small container of fluid before opening the valve will that prevent the air from getting in. This isn't the first time I've done pads, but the other time was on my 95 Blazer and I just followed the Haynes and just made room in the master cylinder when compressing the pistons. Now that I'm better informed, I'd rather not risk getting any junk that could be in the fluid get shoved into anything important. Thank you.

 

i would think if you just opened the bleeder and compressed you should be fine.
there shouldn't be a vacuum there to pull air in so the fluid should be continuous in the line

 

Ok, thanks for the answer.

 

Note that if replacing read pads (assuming you have rear disk brakes) the calipers typically freeze. Be prepared to replace calipers also. Any time I replace rear pads on a Blazer/Bravada/Jimmy/S10 I always replace the calipers. Loaded calipers for the rear is often a very easy solution.

 

I have never had a problem with any of my vehicles by pushing the cylinder back in, and I have been doing it for over twenty years that way. The only time I open a bleeder it to flush the fluid out every couple of years.

 

Could you or someone else elaborate on this? Do you mean that the caliper itself freezes, or just the bolts? How will I tell if it is frozen if it's not just the bolts?

I will of course still be pushing it back in, it's just a matter of where all that extra fluid is going to go. I am only going by what I have read in a few posts here, so I am obviously not an expert. Is opening the bleeder valve to drain that extra fluid going overboard?

 

The reason for opening the bleeder before retracting the piston is to keep crud from being pushed into the ABS unit. Line lock the flex lines on the front calipers, open the bleeder, push the piston back in. When you're all done, gravity bleed until only fluid comes out of the bleeders, then bleed as usual. Don't let the master cylinder run dry. If you do, you will need an ABS capable scan tool to bleed the brakes.

S&T series rear disc brakes: as GunsOfNavarone mentioned, loaded complete calipers are the way to go. The caliper is aluminum and the piston is steel, the aluminum corrodes and causes the piston to bind. Also, the guide pins seize in the brackets. If you don't replace the assembly, the piston will bind, pads and rotors will overheat, (when they overheat, they're junk). Complete reman loaded calipers come with pads, all hardware and the brackets. Bottom line... replace the rear calipers at every rear brake job to avoid having to do it all over again in a couple of weeks.

 

Ha, so much for a quick question. So I will have to bleed the brakes after opening the bleeder valve. What do you mean by gravity bleed? Place the tube in the clean fluid and just open the valve without pressing the brake pedal and wait for the bubbles to stop? Uhh, also what about this locking the flex lines? How do I go about doing that? I wish that my piece of junk Haynes manual actually had all this info so I don't have to ask all these dumb questions.

 

Whenever the hydraulic system is opened, it needs to be bled. To gravity bleed, do not pump the pedal, remove the master cylinder cover, and fill to the "MAX" line. With the cover still removed, open one bleeder and let it drain until no bubbles appear. Close the bleeder and repeat on the next wheel. Make sure the master cylinder does not run dry while gravity bleeding. After all necessary wheels are bled, top off fluid level and install cover. Very slowly push the pedal down about half way, release slowly and repeat until the pedal is firm. Then bleed the necessary wheels as you normally would.

Line lock tools are available in a variety of styles. Some are locking pliers, similar to vice grips, with rounded edges so the rubber line is not damaged when clamping. http://www.craftsman.com/shc/s/p_101...8&blockType=L8 Other tools are a small clamp that fits over the flex line. Remove the wheel and install a line lock on the flex line, open the bleeder, push the piston back into the caliper, close the bleeder, remove the line lock. Bleed as outlined.

 

Hey Captain Hook, thanks for that info! Still haven't started the brake job, waiting for the nice weather that is supposed to come this weekend in New England. There was one thing I was wondering about, maybe someone could answer. When I had the truck jacked up to check the pad wear, I noticed some resistance when I tried to spin the wheels. How easily are they supposed to spin? I read a few posts here about frozen caliper symptoms, such as burning brake smell and truck seems to "drag". I haven't noticed any of these things when driving. The wheel definitely was able to be spun by hand, but there was a small scraping noise. Normal?

One other thing, does anybody think that I could achieve the same results as a line lock tool with a normal pair of pliers with something in the jaws to protect the brake lines? Or is this not a good idea?