Gravity bleeding brakes
- Thread starter eric8
- Start date
Yep. It just won't exchange fluid in the pump circuit unless you activate it.
Overthinking? I put a 12” hose on the bleeder and into a bottle. Pump the brake pedal some number of times and refill the MC, repeating until fresh fluid shows in the hose. Tighten the bleeder, move to the next wheel, repeat
Right rear
Left rear
Right front
Left front
I’ve been fortunate to never run dry and introduce air into the abs. The worst fluid seems to always be down low.
Right rear
Left rear
Right front
Left front
I’ve been fortunate to never run dry and introduce air into the abs. The worst fluid seems to always be down low.
No need for fresh fluid waste, run tube up from bleed screw a few inches before tube goes into empty bottle.
I normally do front left first, front right and then rear corners. Opposite to common practice but there is logic to it.
I have gravity bled for years on several vehicles. Use a small segment of clear tubing that feeds into a clear water bottle with some fluid submerging the bottom bit of tubing. Loop it up from the bleed screw and then down to the bottle. Takes time but after the fluid fills the tubing, I do slow brake pedal compressions.
Keep the master cylinder reservoir full and away you go. Never an issue as I take my time.
Keep the master cylinder reservoir full and away you go. Never an issue as I take my time.
No I was thinking that if there are any bubbles in there, a gravity bleed won't work. You have to get a reasonable flow rate going to shift bubbles. If it's just a fluid change there won't be any bubbles and so gravity bleeding does work. KrisZ said it exactly in the following post.
I haven't had an occasion to try this method on the car but on my bike if the system has been broken into and is full of air I fill it from the bottom upwards using a large syringe connected to the bleed nipple. This forces the air out upwards as it fills and any additional bleeding needed is minimal.
I only gravity bleed if I’ve replaced a caliper. I open the bleed screw (NOT the banjo fitting; you need to get the fluid INTO the caliper and removing it doesn’t do that), and allow the fluid to fill the caliper until it comes out the bleeder.
Close the bleeder and then use the brake pedal to close the gap between the pads and rotor.
Then I bleed brakes the usual method, with someone operating the pedal or preferably with my Motive brake flush tool. If I need to, I have software or my scanners to cycle the ABS.
Close the bleeder and then use the brake pedal to close the gap between the pads and rotor.
Then I bleed brakes the usual method, with someone operating the pedal or preferably with my Motive brake flush tool. If I need to, I have software or my scanners to cycle the ABS.
I had to use the syringe method on my bikes a couple of times as well to sort of “prime” the brake system, as even squeezing brake lever wasn’t getting the air out of the master cylinder. Some newer bikes have a bleeder screw right on the MC for this reason.
With cars the MC is hardly ever drained empty and if it is, you need to bench bleed it first.
I always prefer my method for brake bleeding motorcycles:
Apply brake for 12 hours.
Then you crack the bleeder on the caliper open, and out comes all the air that was pushed into the brake caliper over that 12 hours.
Having the brakes active for 12 hours pushes every last bit of air into the caliper, which is where you want it in order to get it out during the final bleeding process.
It probably would take less than 12 hours, but everyone has a different time table to keep.
Apply brake for 12 hours.
Then you crack the bleeder on the caliper open, and out comes all the air that was pushed into the brake caliper over that 12 hours.
Having the brakes active for 12 hours pushes every last bit of air into the caliper, which is where you want it in order to get it out during the final bleeding process.
It probably would take less than 12 hours, but everyone has a different time table to keep.
I gravity bled for years. I decided to use Mity Vac this time as I was also flushing lines as I was doing front and rear with wheel cylinders. Was taking too long so I used electric ac vacuum pump to create vacuum. Create vacuum then open bleeder, fill cup, dump cup and fill. Each wheel was about 2 minutes and all fluid replaced. Only way for me now.
I have gravity bled brakes enough to drive the car to a place where an assistant pushed the brake pedal to let me bleed them the proper way.
You can also bleed all 4, find a gravel road, let the ABS engauge a few times, then re-bleed if you dont have the fancy scan tools to run the abs pump.
You can also bleed all 4, find a gravel road, let the ABS engauge a few times, then re-bleed if you dont have the fancy scan tools to run the abs pump.
This hasn't worked for me. Need pressure to force fluid in and air out. Turning your key on and off cycles the ABS pump.
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- May 31, 2024
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Not always on all cars.
