How to Do a Brake Fluid Flush Yourself
A brake fluid flush swaps old fluid for fresh fluid at each bleeder screw, and a one-way valve hose or a pressure bleeder kit makes it a one-person job in the home garage.
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A soft pedal after a brake job, dark fluid in the reservoir, or a manual that calls for fresh fluid all point to the same afternoon in the garage. How to do a brake fluid flush comes down to pushing old fluid out at each bleeder screw and letting fresh fluid take its place, without letting air into the lines. A one-way valve hose or a pressure bleeder kit does the pushing.
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Below: the flush in plain steps, when old fluid needs to go, and the gear for the job.
Mityvac MV8500 Silverline Elite Automotive
A zinc-aluminum die-cast vacuum and pressure kit for brake and clutch bleeding, with an MV8510 pump and a 4.5oz fluid reservoir.
Pros
- Vacuum and pressure bleeding in one kit
- Zinc-aluminum die-cast MV8510 pump
- 4.5oz reservoir catches fluid during bleeding
- 1 yr warranty on material and workmanship
Cons
- 4.9 pounds to move around the car
- 4.5oz reservoir fills fast on a full flush
- No master cylinder adapters in the kit list
- No gloves or bleeder caps in the kit list
3L Brake Fluid Bleeder Kit with 1L Brake Fluid
A manual 3L pressure bleeder pump with a 1L waste bottle, 4 master cylinder adapters and a dual-scale pressure gauge, built for one-person brake and clutch flushes.
Pros
- 3L pump and 1L waste bottle in one kit
- 4 adapters: 43.5mm, 45mm, 49.5mm and 50.7mm
- Dual-scale PSI/Bar gauge shows pressure while you work
- One-person operation, with gloves and a wrench included
Cons
- Main components are plastic, not metal
- Adapters fit up to 95% of vehicle applications, so some cars need a different adapter
- No one-way valve in the kit list
- Wrench size is not stated
Liramera 2PCS Brake Bleeder Hose with Gloves
A hose and one-way valve kit with 2 inlet hoses, 2 outlet hoses, clamps, bleeder caps and gloves for bleeding hydraulic brakes on cars, motorcycles and bicycles.
Pros
- One-way valves stop air getting back in
- 2 inlet hoses and 2 outlet hoses in the kit
- Aluminum valves resist rust and corrosion
- Gloves and 4 bleeder caps included
Cons
- Listing calls it 2PCS while the kit holds hoses, valves, clamps, caps and gloves
- No waste bottle in the kit
- No pressure gauge or pump
- Spec table spells the color Sliver
How to do a brake fluid flush
A flush swaps the fluid in the lines, calipers and master cylinder reservoir for fresh fluid. Most brake fluid absorbs moisture over time, and moisture lowers the boiling point and feeds corrosion inside the system. Work on level ground with the car held the way the manual describes, and never rely on a jack alone to hold a car.
Before you start, check the manual for the fluid type and the bleed order for your car, and look at the reservoir cap, which often names the fluid type. Keep the reservoir topped up: if it runs dry, air gets in and the flush starts over.
- Top up the reservoir with fresh fluid before you open any bleeder screw.
- Fit the bleeder tool at the wheel the manual lists, hose on the bleeder screw and the far end in a waste bottle or the tool reservoir.
- Open the bleeder screw and move fluid through, by pedal, vacuum or pressure, until clean fluid comes through, then close the screw.
- Move to the next wheel in the order the manual gives, topping up the reservoir between wheels.
- Check the pedal when every wheel is done: it should feel firm.
- Cap the reservoir, wipe up spills, and put old fluid in a sealed container for disposal under local rules.
With a pressure bleeder, the maker instruction for the SGT kit is to pump to 10 PSI and watch the gauge. With a vacuum kit, the pump pulls fluid through the bleeder screw into the reservoir on the tool. With a one-way valve hose, the valve stops air and old fluid from flowing back while you work the pedal.
When old fluid needs to go
Fluid darkens as it ages, and a pedal that feels soft can mean air or moisture in the lines. A flush also follows brake work that opened the system, such as a caliper or line change. The manual gives the schedule for your car, so follow that rather than guessing.
Use rated jack stands on solid ground, wear eye protection with power and air tools, keep fuel-burning equipment out of a closed garage, and follow the manual for every tool. Read our Safety Disclaimer.
The gear for a brake fluid flush
Each step above needs a way to move fluid out of the bleeder screw without letting air in: a one-way valve hose for simple bleeding, a vacuum and pressure kit for brakes and clutches, and a pressure pump with adapters for a solo flush.
FAQ: garage tools
Can I do a brake fluid flush alone?
Yes, with the right kit. A pressure bleeder with a master cylinder adapter lets one person push fluid through the system, and a one-way valve hose stops air from flowing back while you work the pedal. A vacuum kit also works alone.
What fluid does my car need?
The type your vehicle manual lists, and often the type named on the reservoir cap. Do not mix types, and do not reuse fluid that has been bled out of the system.
How do I know when the old fluid is out?
Watch the fluid at the bleeder screw: old fluid runs dark, and fresh fluid runs clear. When clean fluid comes through with no bubbles, close the screw.
Do I need to bleed the clutch as well?
Some cars share fluid between the brakes and the clutch. Check the manual: if the clutch has its own bleeder screw, bleed it the same way as a brake bleeder screw.
What do I do with the old fluid?
Put it in a sealed container and take it to a local collection point for waste oil and fluids. Never pour it on the ground or down a drain, and keep it away from paint.
Can I just top up the reservoir instead of flushing?
Topping up fixes a low level, but it leaves old fluid in the lines and calipers.
Related: the best brake bleeder kit roundup, gravity vs pressure brake bleeder, the best brake bleeder for solo mechanics and the engine and shop equipment hub.
