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Bleeding brakes, bubbles don't stop

Hi all.
I am bleeding the brakes in my wifes car. I did the first back passenger, fine no prob, then to the back drivers side and the bubbles don’t stop. any ideas? I am using this: https://www.harborfreight.com/automotive-motorcycle/brakes/brake-fluid-bleeder-92924.html

The bleeder you’re using is a vacuum bleeder. With a vacuum bleeder, air can leak past the threads when bleeder screw is opened and you get these tiny bubbles.

This doesn’t occur with a pressure type brake bleeder.

Tester

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Agree with @Tester

I’ve never used a vacuum bleeder that worked very well. I either gravity bleed (one must have patience and some cars just won’t), pressure bleed (modified an extra brake reservoir cap with a pressure fitting for about 6 psi) or have my wife pump the pedal from in the car.

Some posters here say if they coat the threads of the bleeder valve with Vaseline that can help with vacuum bleeding. Me, I’ve never had much luck w/that method. I’ve always done it by pressing on the brake pedal. If you want to try the brake pedal method, connect a clear hose to the bleeder valve, the other end in a bottle with some brake fluid, open the bleeder, then push on the brake pedal, close the valve, etc etc. Well, you know how that works. I get the best results by pushing on the brake pedal gently and slowly with my hand, rather than forcefully with my foot, and I only press 2-3 inches, not all the way to the floor.

If you’ve recently had the calipers replaced, it is possible to install them right left reversed, which makes them impossible to bleed. Make sure the bleeders are pointing up, not down.

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Silicone paste is recommended to seal the bleeder threads, petroleum products like Vaseline should not be used on brake components.

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Pressure bleeding works great but there are too many caps to deal with.

I had a similar fluid feed pressure bleeder with a 1 gallon reservoir that was great on large older trucks with built in cast iron reservoirs but they could make a heck of a mess and it was often on the fender and DOT 3 can really do some damage to paint.

Bleeder tanks are ok with a fleet but a gallon of brake fluid sitting around absorbing moisture can be an issue.

I made this from a spare cap with the seal still in it. It can bleed on corner at a time, check the level, add, bleed the next one. About 6psi gets it done. Wrap the cap area to avoid spray or dribble. Fast and easy for a home shop.

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The only way I’ve ever done it is with someone pushing the brake pedal down, but that is not a good method now. Also I would have to check again but there is a sequence of the wheels to bleed I believe alternating front and back.

Great idea. I’ve always thought about making one like that too, used w/a compressor or just a hand-held air pump. The store-bought pressure-bleeders usually contain a rubber diaphragm between the air pressure source and the top of the brake fluid. Does yours have that feature too? Maybe you don’t need that if you keep the pressure to 6 psi or less?

I believe I had some air in one of the rear brakes on my Corolla. I was hearing a scraping sound back there during braking, which would go away after the first braking of the day and wouldn’t appear again for several weeks, and not until it had rained again. Thought it was just rust on the drums but pulled one of the drums anyway to take a look at the shoes. Shoes had plenty of material left, confirming the rust idea. But the noise started to occur more frequently, and sometimes when it hadn’t rained. So I decided to just replace the rear shoes. Sure enough, when I removed the other drum the shoe material on that side was nearly worn out. I gave both sides a bleeding as part of the shoe replacement, but I think I’ll re-bleed the non-worn side again now I think about, and try @RodKnox 's simplified no-helper-needed brake bleeding idea.

Yep! I use the factory diaphragm inside the cap. It balloons a little as the fluid is pushed through the master cylinder. I push it back to flat when I add fluid. The quick connect allows me to hook and unhook to the compressor easily. I always attach it with zero psi and increase with the regulator until the brake fluid begins to flow into the container I use to catch the old fluid.

When I do a full fluid change, I use the hand held vacuum pump and bottle to suck out as much old fluid as I can before refilling with fresh. I bleed each corner and add a little fresh before going to the next one.

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