Completely Draining Brake Fluid
03-21-2009, 05:55 PM
#1
Instructor
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Completely Draining Brake Fluid
Long story short. Somehow my brakes got Dot 3 and Dot 5 brake fluid mixed. I want to completely drain out the system and put Dot 5 in. All the other posts I have seen involve keeping some of the fluid, which I obviously don't want to do. Any one have some suggestions? Thanks
03-22-2009, 12:56 AM
#2
Flush the system with denatured alcohol, then refill and bleed the system. I use a mighty vac it makes the job a little easier. Ron B.
03-22-2009, 06:05 AM
#3
Melting Slicks
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Hi
I think that if you want to 100 % replace all fluid, you need to remove the brake calipers for draining. The bleed srews are on top and just bleeding will not replace the fluid completely. Also, if there is water in the calipers, it will have the tendency to stay on the bottom and not find its way out the top bleed screws.
If you decide just to replace by flushing with DOT5, assure not to empty the master cylinder tank completely. This will just produce problems to bleed the system later on and the master cylinder might require bench bleeding again. Just suck out the old fluid from the tank, refill with new fluid and start bleeding one brake after the other till new fluid comes out. Watch that the master cylinder never empties and sucks air.
Rgds. Günther
I think that if you want to 100 % replace all fluid, you need to remove the brake calipers for draining. The bleed srews are on top and just bleeding will not replace the fluid completely. Also, if there is water in the calipers, it will have the tendency to stay on the bottom and not find its way out the top bleed screws.
If you decide just to replace by flushing with DOT5, assure not to empty the master cylinder tank completely. This will just produce problems to bleed the system later on and the master cylinder might require bench bleeding again. Just suck out the old fluid from the tank, refill with new fluid and start bleeding one brake after the other till new fluid comes out. Watch that the master cylinder never empties and sucks air.
Rgds. Günther
03-22-2009, 08:51 AM
#4
Drifting
I removed the lines from the M/C and from the caliper and used a rubber hose to connect the M/C side to an air compressor and cleared the lines with compressed air.
so first i pumped most of the fluid out and then forced the dregs with the compressed air.
so first i pumped most of the fluid out and then forced the dregs with the compressed air.
03-22-2009, 09:15 AM
#5
the only way i know to get the system 100% dot 5 now is to disassemble the master cylinder and calipers. 3 and 5 will work in the system together, i.e., you will have brakes, but the dot 3 needs to be completely removed.
03-22-2009, 10:39 AM
#6
Team Owner
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Hi ,
I found, as S489 did, that I had to disassemble the master and the calipers to get rid of ALL the DOT3.
Regards,
Alan
I found, as S489 did, that I had to disassemble the master and the calipers to get rid of ALL the DOT3.
Regards,
Alan
03-22-2009, 01:24 PM
#7
Race Director
There are drain plugs on the bottom end of the calipers also. Might want to drain completely, Blow it out, Fill with denatured alcohol, pump the pedal, Drain completely, blow it out, fill with DOT 5, Bleed.