Gravity Brake Bleeding

I've solo bled brakes since I can't remember with a length of vinyl hose running into the bottom of a jam jar with a hole in the lid. Fashioned a piece of coat hanger to hang the jar higher than the bleeder screw. Air has no choice but to go up into the jar with the fluid. The fluid accumulating in the jar is nature's check valve. Monitoring the fluid level in the master cylinder, pump the pedal 10-15 times and then go look at the jar. It's satisfying to see old, dark fluid accumulating in the jar and clean, clear, bubble-free fluid going up in the vinyl hose. Only problem is that this way is slow and lonely. But it's worked for me for a long time.

 

Going on 8th year. Original fluid, original brake pads You don't need to replace the fluid.. I've never done on my Toyotas that I owned. I live in rainy PNW and surrounded by hills. Never had any problems with brake.

 

Water absorbed over time lowers the brake fluid's boiling point.

 

I kept my cars for 20 years on average.

 

You'll find if you don't change it frequently that braking power diminishes in heavy breaking and hot weather applications. Also, your caliper pistons and bleeder screws will rust out faster and cause issues in the future. Usually a need to replace the entire caliper.

 

Moved to Indiana since 2008, middle of rust belt with cold winters and humid summers. Never saw issues with water in brake fluid.
The only problem I've seen was people messing with the bleeder screw, either trapping air or breaking it off.

If you really want to replace the fluid, just suck some out of the reservoir with a turkey baster, refill with fresh fluid. Drive few days and repeat. Eventually, you will get most of the oil fluid out.

 

Do you have a TRD Off Road or Pro? If so gravity bleed may not work. You can still make a DIY bleeder bottle to bleed the brakes by yourself. Just make sure the hose is airtight against the bleeder nipple. Use a ziptie there if necessary.

 

When you brake aggressively (panic stop) on the freeway the brake fluid down at the wheels actually boils. Microscopic air bubbles form over time and allow the pedal to get soft.

I'm not dipping test strips in every car but when it's turning green from moisture absorption I'd say a flush is in order.

 

The brake lines actually hold quite a bit of fluid, but I have done the turkey baster method in between brake fluid flushes as a temporary solution.

 

I wouldnt gravity bleed a brake system in a newer modern vehicle....
Been a mechanic for 32 years...
Too many valves in the system, not worth the risk in not doing it right..
Find someone, shouldn't take long at all with some help...
15 minutes....

 

This afternoon did it and IMO is the easiest way to do it and I have never done any form of bleeding brake lines. I didn't need any tool (except 10 mil wrench) & no help. The whole thing cost me less than 20$. I read and watched about different ways to do it. Every single one of them had a possible downside to it and you have to buy different tools or need a helper. The gravity bleeding got no downside, except you let the master cylinder container to run out of fluid.

Didn't take the wheels off & I did all 4 wheels at the same time starting from rare passenger, rare driver, front passenger, and front driver side. It took less than 2 hours. However, I would highly recommend to do two wheels at a time. Start with rare passenger, rare driver side. Then, front passenger & front driver side. It was my first time and couldn't be easier than this. Make sure to put buckets under rotors and watch the fluid level in the master cylinder, top it off when needed. Wipe & clean the area with brake spray.

 

Air will not get in the line and no need the jar hang higher if you don't pump. Just let it drip. The most helpful video that I have watched and I have watched many.

https://www.youtube.com/watch?v=aegLRk-w0Cg&lc=Ugxn4zO-4FLre7R85DB4AaABAg.AGAnCAl4vgFAGBLRyMRhj9

 

Gravity bleeding is good for simply bleeding out air but isn't as effective at flushing out old fluid and contaminants.

 

I poured 32 Oz of brake fluid in the master cylinder. Where did it go? it came right into the brake lines by pushing the old fluid out though the open bleeders. I had doubts until I did it myself. It's the simplest way, open the bleeders and let the gravity work. If you moving the container jar above the bleeder level, you are not doing gravity bleeding. I am not saying that will not work if you know what you are doing. The downside is that you have to pump the brake and that make it possible/probable for air getting sucked in the line if you lose the vacuum in the line going into jar for any reason. For gravity you just need to take your time and only pay attention to the master cylinder's fluid level.

 

This helps, but doesn't address getting the fluid out of the calipers or wheel cylinders. Moisture(water) is heavier then brake fluid and will settle in the lowest areas. IMO, getting that first several ounces or bleed cycles out of those components is most beneficial.