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DIY Brake Bleed

46K views 78 replies 32 participants last post by  Stealthn  
#1 ·
You should bleed your brakes and refresh the fluid every two years, more often if you track you car. Brake fluid is hydroscopic, meaning it adsorbs water just sitting there and with minor use. The fluid becomes more corrosive over time and can lead to poor performance or just failed sticky brake calipers.

I rate this a 2 out of 5 bloody knuckles. You need some not-so-common tools and well.....you're dealing with brakes.
1.5hrs Total with wheel removal/installation.

Proceed at your own risk:
You're dealing with brake fluid which can wreck paint, plastic, and your eyeballs.
The most common mistake is OVER-tightening the bleeders which strips them out. The fix is a new caliper.
The next most common mistake is running the master reservoir dry.......which can be a pain to completely bleed the system.

What you Need:
Jacks, lug nut wrench, torque wrench, for removing and reinstalling wheels.
Metric box wrenches for the bleeders.
DOT 4 Brake Fluid (Porsche or other high quality)
Catch can and tube
Paper towels

What I'd recommend you get:
Pressure bleeder
(2nd Option) Vacuum bleeder
Magnetic large catch bottle
Small funnel
Rubbing alcohol for mistakes.

Procedure:
Start by jacking up your vehicle and removing the wheels. There's other threads on this.
You CAN bleed the brakes without removing the wheels, but it will make it much more difficult..... and you'll likely scratch your wheels trying to loosen the brake bleeder. Just pull them all off. You can do one by one....but again, more difficult.
Good time is when you're swapping to winter wheels.

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Take Note of the Reservoir Level
Next get your power or vacuum bleeder and verify the cap fits the reservoir.
There's two ways to use a power bleeder. You can fill it with brake fluid, which when pressurized constantly replenishes the master reservoir. Meaning you never run the risk of pushing air into the brake system. This is the fastest method as well. Since you just go around opening bleeders and flushing the system.

The downside, is if you have a leak, you get brake fluid everywhere. If you forget and open the system at the cap, brake fluid everywhere. It also trashes the brake bleeder unless you thoroughly clean it with rubbing alcohol.

The 2nd way is just to use it as a pressure vessel. You have to carefully watch the master reservoir to make sure it doesn't go empty. It takes more time, more refills, more stop/starts, but it eliminates a potentially messy mistake.

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You'll also need brake fluid. Get the large container, and get two of them. Remember, you're not just bleeding but flushing the system and you don't want to run out. I did it with one of the standard Porsche cans, but barely.

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Next you will need a catch bottle, tube, and box end wrench. This one was relatively cheap and worked like a charm. I'd highly recommend these two tools for your toolbox. Fit the wrench, remember lefty-loosen, then add the tube. You're going to have to unscrew the bleeder about 120 degrees for good flow, don't need much more than that. NOT YET. A good trick is to start the wrench at the farthest clockwise it will fit. That's a good point to STOP tightening the bleeder when done.

(Picture is with bleeder OPEN)

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Nows the point to start bleeding. Either fill the pressure bleeder with fluid or just connect it dry to the reservoir. Pressurize it to no more than 10psi and check for leaks (if you filled it). You can then move to one of your brake calipers and start bleeding. The fronts have an inner and outer. Start at the inner to flush, then the outer to final bleed/flush. The rears have a single bleeder.

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Be sure to always have pressure on the system (power bleeder) or vacuum (vacuum bleeder) before opening the bleeder. Always close the bleeder first before relieving pressure. This keeps air /dirt out of the system.

Starting at the right rear (longest run), flush the system until you see fresh fluid / refill the reservoir 2 times / or bleed a 1/2 bottle of fluid. Maintain pressure in the power bleeder above 5 psi and don't let the master reservoir drop too much below the bottle split line. It gets hard to see below that and easy to go too low.

Move to another caliper and repeat. The goal is to keep flushing until you see fresh (clear-ish) fluid at each one. This roughly takes the entire bottle of Porsche brake fluid by the time you get all 4 corners. Repeat the 1st caliper you did again at the end, checking for fluid color and any air.
When complete, make sure all bleeders are tight and caps are replaced.

Fill the reservoir to level when you started. This keeps it from overflowing if you back the calipers off during a brake change (and forget to suck some out of the reservoir).

BEFORE reinstalling the wheels, pump the brake pedal until it is ROCK HARD. It should take 1, maybe 2 pumps to use up the vacuum assist and verify you have good pedal feel. If it feels spongy no matter how many time you pump it, you have air in the system and need to bleed each caliper again (inner/outer in fronts). Check for air bubbles.

Reinstall wheels, check brakes again, take it for a test drive checking brakes at low speed.
 
#4 ·
Great post, thanks for taking the time. Some excellent tips and pictures!
 
#5 ·
Very nice and detailed instruction.

Alternatively, one can accomplish this by simply sucking out brake fluid from the reservoir and refilling with new brake fluid. Do this a few times with some driving/braking in between. Very easy and clean!
 
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#7 ·
I did see some air bubbles out of each front caliper and brake pedal feel was maybe improved a bit. It was worth doing the flush for piece of mind. The fluid was a shade darker so it was time for a change.

Changing the fluid in the reservoir only gets about 1/4 of what is in the system. All of the ABS valves, lines, calipers would never see new fluid.

I should have noted you can do this with a 2nd person pumping the brake pedal. But I think you'd have to pump it 500 times or so to flush the system. Opening and closing the bleeder each time. That method is best for just a quick bleed. I have a mighty vac bleeder that is slower, but I've always had issues with it pulling air next to the nipple so you can't tell 100% the brakes are bled.
 
#8 ·
Not sure if this was in the original post, but brake fluid eats paint, so be careful with it.

Vacuum bleeders generally don't work well because they suck air around the threads of the loosened bleeder screw.

All you really need is a catch bottle and tube. I have a fancy one with a magnet, like the one shown in the photo. I think it was $7. Then you can use the two person method, which is foolproof and does not take a lot of pumps. Maybe 20 per caliper to be safe. Or you can just start with some fluid in the catch bottle, immersing the tube in the catch bottle into that fluid. Then you pump with one person and the fluid will be drawn from the reservoir. One more thing, don't pump the pedal too fast, and don't go all the way down to the stop. Just go most of the way down at a medium rate. It's super easy.
 
#10 ·
Brake fluid is circulated when you apply the brakes. If you do the sucking and refilling a few times with driving in between you can get most of the old fluid out.

I have used this method on my BMW for the past 6 years. Usually after doing this for 3 times the fluid gets clear like new. It works well and you don't really need to get 100% of old fluid out. It is all relative.

Just another alternative for those who are not comfortable doing the flush themselves.
 
#11 ·
Brake fluid is circulated when you apply the brakes.
Are you sure? It gets circulated back to the master cylinder? I can't say I'm an expert, but I've never heard of this. How does it get back to the master cylinder?
 
#12 ·
Below is an answer to the brake fluid circulation question I found online. From my own experience, I have seen new fluid refilled in the reservoir gets dirty quickly, which seems to validate the claim too.

"Yes. There is a lot of movement.
Some more than others, and an ABS system isn't certain.
At the shop we have performed and recommended turkey baster type flushes for people with economic restrictions. It usually helps or fixes some problems, and is certainly good maintainance.
My latest experience was a Chevy work truck. We had the owner suck out his master cyl and clean it, then refill with fresh fluid every couple of days. It would get black rapidly, then started to clear up, and his rear brakes started working properly again.
Of course bleeding the system is faster and better. But we have to deal with people with no money and broken off rusted bleeders.
I turkey baster my personal vehicles as a regular maintainance procedure
-quick and clean for PS and brakes."
 
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#14 ·
I guess it's better than doing nothing, but I'll stick to the method that every mechanic I know of has used for decades. I can't see the logic of circulating contaminated brake fluid through the system when it's relatively easy to avoid doing so.
 
#18 ·
You certainly got a valid point. This is still debatable.
 
#19 ·
I would add a word of caution to those w/o a pressure bleeder who use the two-man (or man-woman) system of bleeding by one pressing on the brake pedal while the other operates the bleed nipple. You should not allow the brake pedal to go completely to the floorboard and that can be accomplished by the operator on the bleed nipple opening and closing quickly. Once closed, the pedal travel stops and the pedal can be allowed to return to the top. The reason is simple: If the pedal is given full travel, the master cylinder piston goes completely into the bore. In doing so, it can roughen the piston seals, leading to premature failure.
 
#22 ·
I concur...and 1 bar (approximately 15 psi) is more than sufficient.
 
#30 ·
I think Porsche presumes that its cars are driven hard, so maintenance requirements are set up accordingly.

If your brake fluid tests out good, you don't really need to change it so soon.
 
#31 ·
#32 ·
Brake fluid tester. You can find it on amazon.
 
#35 ·
Some good info here. Thanks!

From talking to other gearheads over the years, my 2 cents on the brake fluid circulation is this....it’s a function of heat. As the fluid gets hot from use in the calipers, it expands. This pushes some fluid into the reservoir. Once cooled it draws fluid down. This would mean that pulling old fluid from the reservoir and replacing it with new will have some impact on the quality of the overall system. A flush at the caliper is always better, but man is the turkey baster easier.

Back when I had cars that ran on Dino oil and needed changed every 5k miles, I would also suck the brake fluid in the reservoir and refill. This seemed to keep the quality at at constant “ok” level. I would apply this method to many fluids... PS, transmission, transfer cases. Heck, I even had a car for a while that leaked and burned enough oil to never need an oil change-just add a quart every couple gas fill ups. I sure don’t miss that car.
 
#36 ·
Heck, I even had a car for a while that leaked and burned enough oil to never need an oil change-just add a quart every couple gas fill ups. I sure don’t miss that car.
With my car in high school when I pulled into a gas station I would tell the attendant (I live in NJ, no self serve gas) to "fill it up and check the gas":D
 
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#38 ·
Agreed that speed bleeders are easier than the pressure bleeder method. I have the pressure bleeder for my Toyota/Lexus vehicles, but prefer speed bleeders and eventually converted them to speed bleeders.



At Rockauto site when looking up Calipers for the 2015 Macan, the Centric 14233299 kit for the 345mm rotors has a thumbnail of the specs. It says they're Brembo brand calipers and use 10x1.0 bleeders. For the rear Centric 14233675 kit, it says TRW brand calipers with 10x1.0 bleeders. I don't know how accurate this information is. I'll try and verify this when I get underneath the car. If there are enough threads showing, I might be able to measure it. The Macan S uses 350mm rotors while the Turbo uses 360mm front rotors. I'm guessing Centric is referring to the 350mm Macan S rotors when they say 345mm.
 
#40 ·
Getting this back from the past only to add some information.

Changing the fluid in the reservoir doesn't help at all, the fluid in the reservoir is not exposed at the same temperature changes than the fluid on the calipers, this fluid stays on the calipers and does not recirculate back, so the only way to do it is by opening the bleeder.

The best cleaner for brake fluid is WATER, not alcohol, not brake cleaner fluid (which by the way cleans everything but the brakes)

The new DOT 4 fluid will affect the paint if exposed for a long period, the new generation of fluids is not like the old ones, the formula changed substantially and now even if you pour a quart of brake fluid in the hood of your car it will drip and not even affect the clear coat, just rinse it with water and it will be fine.

Considering the money you can save by doing this on your own I recommend a power bleeder, it's a MUST for this job, no matter what happens, if you have fresh fluid coming into the system and the system is pressurized nothing bad can happen.


For under $60 you can do the job like a pro.
 
#41 ·
Considering the money you can save by doing this on your own I recommend a power bleeder, it's a MUST for this job, no matter what happens, if you have fresh fluid coming into the system and the system is pressurized nothing bad can happen.


For under $60 you can do the job like a pro.
+1 on the power bleeder
 
#43 ·
There's no easy way to remove it, it has 3 clips around so when you manage to bend two the third gets stuck in, take your time and eventually it will come out.
Can I ask why you want to remove it?
You can flush your brakes with the screen installed.