Changing brake fluid

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texasmike

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I haven't had the top off of my brake fluid reservoir for four years so I decided to take a look. The level was fine but the fluid is very dark. It would probably be a good idea to change it so can anyone tell me the best way to do that without getting air into the system? Thanks for your time, and I don't take it lightly because I realize it's one of the most important items we have to offer/sell.
 

Ricko1966

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If you are creative you can make a brake fluid exchanger out of a garden sprayer. Brb with details and pics. One is pressure one is vacuum. I've used both at work. I like pressure better. Made one for home use I'll find a pic. Home made a piece of scrap aluminum plate with rubber glued to it some all thread a fitting and a 4 dollar garden sprayer. Internet search motive products 0105 and 1105. If you better pics of my home brewed rig. Let me know.
 

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75gmck25

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If you have a newer design brake booster with a screw-on reservoir cap, it’s easy to connect a pressure bleeder and just bleed each wheel, one at a time. The bleeder both provides pressure and ensures you don’t introduce any air.
Older trucks like mine have a flat brake booster cap with a wire bail retainer, so you have to use a different type of adapter to seal to the booster.

You can do the same bleeding process without the pressure tank if you have a helper who makes sure the reservoir stays full and you don’t pull in any air.
For the manual process, take it easy with the brake pedal when you are bleeding, and just press the pedal about 1/3-1/2 way down to get pressure. There is a temptation to press the pedal until it goes to the floor, but this pushes the piston way beyond its normal travel. Old piston seals don’t like that abuse.
 
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Redfish

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Mitey Vac. I love this thing. I wasted my money on a cheap Harbor Freight pneumatic brake bleeder and ended up buying the Mitey Vac to replace it. It works, it's clean, and you don't need two people to bleed the brakes.

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texasmike

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I also have one of the Mitey Vacs. Should I suck the reservoir dry, refill it and then start with the right rear wheel, then the left rear , with left front last, making sure to refill after each wheel.
 

WFO

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I still do it the old fashioned way. Have someone pump the brakes up while I bleed from the furthest brake first, and working my way to the closest brake to the master cylinder.
Occasionally refilling the master before it gets low.

I like to use a clear hose on the bleeder nipple to more easily see the air bubbles.
 

Craig Nedrow

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I use the same exact method as WFO, except that I use a mighty vac, as most of the time I am alone in the shop. Do the longest run first and progress to the shortest, usually RR,LR,RF,LF. Don't run it dry, or you get to do it again.
 

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