emptying old brake fluid
Asked by cbbv Apr 16, 2013 at 03:36 PM about the 1990 Opel Corsa
Question type: Maintenance & Repair
The car has double master cylinder system and its is diagonal brake system.front right+rear left,front left+rear right.on the front -disk brakes and on the rear-drum brakes.i have question that related to the emptying of the brake fluid before adding new fluid.1)i begin(beginning with the front wheel as the manual said) to empty the old brake fluid with an assistant that push and release the brake pedal while i open and close the bleed nut until there is a moment,that the fluid stop to get out(in the resevoir,you can see,that one part of it is empty).after that i do the same to the other front wheel,till the fluid stop get out and the resevoir got empty.(as i said,it is diagonal system)at this moment,is it mean that all the old brake fluid that was in the system included all the lines to the all wheels from the master cylinder gotout completely?is it mean that emptying the fluid at one front wheel,also take out the fluid from the diagonal rear wheel line?(because when i continue to the rear wheels,it seems that no more fluid got out.)or the lines,after the master cylinder,are still have brake fluid,only that the master cylinder can't push the fluid out(maybe air that been compressed?) because the resevoir is empty?and is it only make me think that all the fluid got out?Please,I do not look for advise how to make the bleeding or how to proceed .i would like,only, to get answer to those specific questions that i asked.thank in advance
20 Answers
migration_judge_roy answered 11 years ago
use a rag to get all the gank out rinse with a bit of clear fluid, use a soft cotton rag, get every last bit and refill with clean fresh fluid...don't forget the little screen in there as well~ bleed with a piece of aquarium hose~
migration_judge_roy answered 11 years ago
have your assistant hold off while you refill the master three times to get all the bad stuff out~
i am sorry,but the answers are not related to my question.i didn't ask what is the process of the bleeding.please,pay attention to my questions?
migration_judge_roy answered 11 years ago
matters not drum or disc, the procedure is the same. One might note how much "meat" is left on the pads and the narrow side of the shoes (if you can get an eyeball in there) and if the disc has a worn "shoulder" like MINI's do, the general condition of the vented rotors if both sides seem to be wearing equally, and if perhaps the caliper does not squish side to side 'cause the slides grease has gone soapy~
migration_judge_roy answered 11 years ago
not quite sure why you're bustin' my chops~ I did the best I could, I've got a repurposed bicycle pump from my mechanic days 93-96, so I don't need to steal the chef's baster...you can find them at Dollar Tree~ sheeshsky why so verbose?
migration_judge_roy answered 11 years ago
air gets pushed out with three thousand PSI and do not worry about it~
migration_judge_roy answered 11 years ago
okay, I get....slow down....right. 1.) there is a little nipple on each of the brakes called a bleeder valve 2.) connect a short piece of acquarium tubing to it and the other end to a vacated drink bottle (but hold of on this for now) 3.) There is a reservoir with a rubbery cap with brake fluid in there 4.) this brake fluid is old or missing, never mind we will 5.) clean out the old brake fluid with a suction device (a soda straw is not recommended brake fluid is corrosive) 6.) get it nice and clean with a soft cotton rag. 7.) replace the screen and fill with fluid just short of the top. 8.) have an assistant at the ready on the brake pedal. 9.) bleed all four wheels starting drivers side (easier to holler up) 10.) okay press the pedal and hold 'er down 11.) while simultaneously you'll turn the bleeder and fluid will fill the bottle, when it slows turn the bleeder shut 12,) top off the reservoir with fresh fluid.....repeat until all four wheels are bled~ apologies for expecting you to know all about cars and stuff~
you said"air gets pushed out with three thousand PSI and do not worry about it~"(maybe this is part of the answer)so by that do you mean that after i don't see anymore brake fluid that go out from the bleed screw,is it mean that all the brake fluid in the system,included the pipe lines are empty from brake fluid?
"is it mean that emptying the fluid at one front wheel,also take out the fluid from the diagonal rear wheel line?" -- No, taking fluid out of the front wheel will not take fluid from the rear line. You may not see as much old fluid at the rear because you are only clearing the small line to the rear.
so can we come into conclusion,that if the resevoir is get empty and we continue pumping from all the wheels(without refill the resevoir)all the old brake fluid in the line that is in the master cylinder and between the master cylinder and the wheels will get out?
migration_judge_roy answered 11 years ago
air squishes, fluid does not squish. we need to get the squishies out of town, replace with awful paint-destroying brake fluid.~
You do not - repeat do not - run all the fluid out. If air gets into the ABS block, it takes special procedures and tools to bleed the air out. -- I did see a video once where a guy used a oil can to squirt brake fluid from the wheels back to the reservoir. He started out with the reservoir empty and pressed the oil can handle like a squirt gun. He had a piece of aquarium tubing on the oil can going into the bleeder valve nipple on the brake.
this is an old car.it doesn't have any ABS.what is going with you guys?the only thing that i want to understand is :if the resevoir is empty and there is left brake fluid only in the master cylinder chambers and in the pipes that located between the master cylinder and the wheels and my assistant keep on pumping the brake pedal,will all the brake fluid get out or from this point(the moment that the resevoir is empty)the brake pedal action will not get the rest of the brake fluid unless we refill the resevoir? this is my only question .can someone answer for that,but only for that,please.
