Ford Focus Brake Fluid Replacement / Bleeding

I had no idea when this had last been changed and it didn't look very fresh so I decided to change it. The fluid in my car is dot4 fluid but I replaced it with dot5.1 which is compatible. Be careful though, dot5 is different and mixing dot5 with any other brake fluid will result in a sludgy mess within your braking system.

The way it works is you unscrew a bleed nipple at each brake. As you depress the brake pedal, the fluid runs from the tank in the engine bay through the system and out of the bleed nipple. Further evidence that the brake fluid had not been touched for a while was found when locating the nipples. They were in a state and took some delicate work and lots of WD40 before they would budge. Here's one at the rear drum brake soaked in WD40:


I bought a brake bleeding kit that fits over the nipple like thus:


You undo the nipple 1/2 turn and then push the brake pedal. It is a good idea to tighten the nipple again before releasing the brake pedal so you do not suck air into the system. For this very reason, I recommend you get yourself an atomicpanda to help push the brake pedal as you loosen and tighten the bleed nipple.


You start on the wheel furthest from the brake fluid reservoir and gradually work towards the closest to the reservoir. As the fluid level in the reservoir decreases, top it up with fresh fluid. This should be done before the fluid level goes below the min mark otherwise you'll need to bleed the system again. You continue on each wheel until the browny fluid goes clear, a sign that the system is now filled with new fluid. Here is the front brake being done:


There was a little bit of air came out with the old fluid. Too much air leads to a spongey feeling pedal. As such, my brakes now feel a little bit more solid, which is a good thing. A quick test drive shows that the brakes still work. Success. Oily, manky success.