Brake Fluid Reservoir - Emptying?

[rtflew]

Hey all - first post, I've been reading the archives for a while, but only just got registered successfully! Something about the image verification deal wasn't working right on my computer for the longest time, anyway... I have a2002 Tahoe LT 4x4 with the auto-4wd with about 153K on it. I've been working through the "big" services for 100K & 150K recently, and ran into a problem doing the brakes. When I tried to empty the brake fluid reservoir like I do when replacing the brake fluid on my motorcycle, it didn't work as expected. I usually just pop the cap off the reservoir, use a turkey baster to suck out all the old fluid, fill with new, then start bleeding with the vacuum bleeder. With the Tahoe, you can't get all the fluid out of the reservoir - theres that front-half that you can't get to. So I wasted almost a full bottle of the DOT3/4 Synthetic fluid I'd gotten at Napa just that morning (yesterday) when I realized that the dirty fluid kept coming out of the bleeders - peeked back at the reservoir and saw the clean fluid had mixed with the dirty fluid, so it was still blue / green.

Ideas? Suggestions? What is the trick I'm missing?

Thanks!

RT

 

[chauncey0337]

Can't you bleed the rest out by pumping the brakes?

 

[Kaotik]

+1 i would pump the brakes til it empties then fill pump again til you see clean fluid then fill and bleed it may waste alot of fluid but at least youll know theres nothing but fress fluid in the whole system

 

[Thumper8302]

+1 i would pump the brakes til it empties then fill pump again til you see clean fluid then fill and bleed it may waste alot of fluid but at least youll know theres nothing but fress fluid in the whole system

agreed

 

[taylorjm]

Wasn't there some deal about how you shouldn't completely drain the reservoir anyway? For some reason, I thought you were only supposed to take out about 3/4 of the fluid, add the new, bleed it and be good. Something about if you suck out all the fluid you would need to bleed the master cylinder or it would somehow affect the abs system if it was bled dry.

 

[sparg93]

DO NOT bleed the reservoir dry!! If you get air into your system, you then have to re-bleed the entire thing to get the air out.

There should always be some fluid in the reservoir when bleeding.

Also, when you bleed, always start from the farthest tire from the master cylinder and move closer. So if your master cylider is on the driver's side, start with the rear passenger tire...then move to rear driver's tire...then passenger tire, the, driver's tire.

 

[SunlitComet]

+1

it may just take some more time and fluid to get most of the dirt out. But it is already improving fluid quality anyway just buy doing it at least once.

 

[rtflew]

Okay - thanks guys. I'll just plan on going through lots of fluid! Thanks for the replies! RT

 

[taylorjm]

Let me know what you do and how it works. I have to do mine soon.

 

[NC_John]

Let me know what you do and how it works. I have to do mine soon.

I just did mine about a month or so ago. When I got the old fluid out (syringe) I noticed the resevoir was still filthy. I ended up removing it, washing it out with caustic (degreaser), then flushing it with water followed by lots and lots of denatured alcohol and compressed air. Finally I sloshed around a bunch of new brake fluid to make sure it was ready to go. If you don't mess with the brakes while the reservoir is empty or removed, you will not get air in the system. I'm glad I did it. I figured there was no sense in going through the hassle of exchanging the fluid and still having a filthy reservoir to contaminate the new stuff.