Lesabre Brake fluid capacity

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I'm NOT in Arizona; I'm in a suburb of St. Louis, MO; but it was a heat index of 102 yesterday. My garage is NOT air conditioned. I did a front pad slap; had less than 1/8" remaining on pads, I considered pad slap necessary for safe driving...then I got on my spreadsheet where I keep track of maintenance and noticed my brake fluid was last (power bled) almost 3 years 62K ago. It's too hot and I'm too lazy to jack up all 4 corners, remove wheels, hook up the Motive bleeder and go around the car twice to all 4 corners so I just used a syringe, flexible tubing and a couple 600 ml beakers. I vacuumed the master cylinder all but dry; removed 450 ml fluid and replaced 450 ml fluid. My question (which I feel only experience can answer) is; what is capacity of the total system? What percentage of total fluid did I remove? I know several places I CAN'T find the answer; I have a GM factory service manual for the 2003 Lesabre, page 0-30 maintenance and lubrication specs does NOT list BRAKE fluid capacity.

Brake fluid 7.12.20 2.jpg
 
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8,861
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Marshfield , MA
You accomplished very little. Wait until the weather is cooler. Using a syringe on the MC reservoir is working from the wrong end. The really bad stuff with water in it is right behind the bleeder screw. As for a system's capacity it is the min/ max lines. If you're gonna do a brake bleed , get a qt . For a flush get 2 BF is cheap and is virtually identical with any brand of to the spec. for the DOT #grin2
 
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In all my years of owning vehicles, I have NEVER seen the manufacturer list the brake system capacity. I have always ordered the OEM shop manual/manuals for every new vehicle I purchase and never have seen how much brake fluid a system takes. When I change my brake fluid every other year I purchase two quarts of Valvoline at AA and use it.
 
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I am assuming you have a 2003. Pad slap is about all you can do on the fronts.If the brakes weren't dragging, the calipers should be fine. Unless they were in VG shape, I would have yanked and replaced the rotors. Would take five minutes. When I bled my 97 Lesabre, I did all fours with a little more than a quart. It all depends how much bleeding is done to get it clean at the wheels. The syringe job at the master cylinder was a waste of fluid. No new fluid is going to make it out of the master cylinder. No short cuts when it comes to brake bleeds.
 
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Thanks for answers, guys; I appreciate it; my rotors are NOT in bad shape and I have a new set on shelves along with plenty of new brake fluid in unopened containers; but sometimes answers give rise to new questions, such as andyd saying "The really bad stuff with water in it is right behind the bleeder screw." OK, obviously, all the wheel cylinders are LOWER than the master cylinder, so is water heavier or lighter than brake fluid? Well, the answer is pictured below. So why are bleeder screws on TOP of the wheel cylinders?

Brake fluid & water.JPG
 
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Originally Posted by Hall
The bleeders are on top to evacuate air more easily
Thanks; this is obvious, so why aren't there bleeders both bottom & top. IF you have water in the system, it's going to REMAIN in the bottom of the wheel cylinders, no?
 
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I would start any fluid flush by doing the Reservoir first, (as you did). That way your NOT sending that dirty fluid thru the lines. Wait for cooler weather and then do a complete flush.
 
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The volume of the wheel cylinders, relative to the output of the master cylinder is such that when bleeding one cylinder at a time, you can pretty much get most of the the fluid sitting in the cylinder out in each pump. If you bleed long enough to see clear fluid coming out, then you're good to go. To understand why this is the case, you need to understand how brake fluid works. Brake fluid is naturally hygroscopic, meaning it absorbs moisture very easily and will combine with it. This is important for safety as it prevents pockets of water from forming in the brake system which can turn to highly compressible steam when heated and cause you to lose brake pedal (i.e hydraulic pressure). All cars on the road except for fresh off the assembly line will have some moisture in the brake system and this is OK (except for maybe track cars). Brake fluid has to absorb about 4% of water by volume before it becomes fully saturated and pockets of water can form. The practical effect of this is that you don't have to get every last bit of old fluid out to regain moisture control. Simply replacing most of it will get you well below that 4% threshold and any tiny pockets of water will get re-absorbed into the fluid. I don't think you wasted your fluid vacuuming out the master cylinder. That fluid will have water and contaminates in it, too, if not as much as in the lower sections of the system. I always suction the master cylinder out and replace the fluid before bleeding so I don't have to bleed as long to get clean fluid at the wheels.
 
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Small amounts of water will mix with brake fluid. If you have so much water that it phase separates you have a big problem. Someone did a test of adding dye to the fluid in one wheel cylinder then returned the car to service. Within a short time it was evenly distributed to the master cylinder and all the wheels. Brake fluid moves around.
 
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In the shop
Originally Posted by Ihatetochangeoil
Originally Posted by Hall
The bleeders are on top to evacuate air more easily
Thanks; this is obvious, so why aren't there bleeders both bottom & top. IF you have water in the system, it's going to REMAIN in the bottom of the wheel cylinders, no?
I don't know why to be honest. If you have any water in a brake system you have more problems than where the bleeder screw is. Sorry, but it's maybe not practical to have 2 bleeder screws on a small wheel cylinder. Just my dumb, redneck 2cents
 
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You did better than not doing anything. My MC reservoir doesn't look as bad as yours but thankfully it's only deathly muggy six weeks a year here.
 
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Originally Posted by mk378
Small amounts of water will mix with brake fluid. If you have so much water that it phase separates you have a big problem. Someone did a test of adding dye to the fluid in one wheel cylinder then returned the car to service. Within a short time it was evenly distributed to the master cylinder and all the wheels. Brake fluid moves around.
Diffusion is different than mixing. The dye may have diffused from the high concentrated caliper to the other areas, but I can't imagine that the fluid itself moved around so that the new fluid in the master cylinder circulated to the calipers. After your experiment was over, they ended up with dyed new fluid still in the master cylinder and less dyed old fluid in the calipers. I suppose this could reduce the percent of moisture in the calipers, but you would be contaminating your new fluid with moisture at the same time. It seems much more prudent to do a proper brake fluid exchange. As elge stated, its better than nothing.
 
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Originally Posted by mk378
Small amounts of water will mix with brake fluid. If you have so much water that it phase separates you have a big problem. Someone did a test of adding dye to the fluid in one wheel cylinder then returned the car to service. Within a short time it was evenly distributed to the master cylinder and all the wheels. Brake fluid moves around.
I'm not buying this. Not calling the poster a liar, I simply do not believe the claim of putting dye in brake fluid. https://www.ecfr.gov/cgi-bin/text-i...ue&node=se49.6.571_1116&rgn=div8 Electronic copy Code of Federal Regulations; scroll down the page; S5.1.14 Fluid color. Brake fluid and hydraulic system mineral oil shall be of the color indicated: DOT 3, DOT 4, and DOT 5.1 non-SBBF—colorless to amber. DOT 5 SBBF—purple. Hydraulic system mineral oil—green. Data is current as of July 9, 2020
 
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Originally Posted by eljefino
You did better than not doing anything. My MC reservoir doesn't look as bad as yours but thankfully it's only deathly muggy six weeks a year here.
His brake fluid has been in there three years, I doubt that the fluid is in really bad shape where this is that critical now. I have had no problems going longer than that.
 
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8,861
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Marshfield , MA
ATE used to make a blue colored BF. It was supposed to be alternated with the amber BF as a quick way to know when the used fluid was expelled. Track rats change BF all the time. That ended when DOT 5 came out. Noticed OP was using AMSOIL BF. Wondered if the dry boiling point was higher than the VV from auto parts stores? I spent way too long one day reading different brands for their dry boiling points. Not enough difference to make any difference. Oh, and all BF is synthesized from methane, IIRC grin2
 
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