No brake pedal pressure after bleeding

I replaced pads and rotors on my 2013 prerunner. When removing one of the calipers I didn’t pay attention and removed the wrong bolts to the caliper instead of the bracket bolts thus opening the caliper and letting air into the system but the master cylinder was never less than half full. I replaced the calipers and bled the system twice. A lot of air came out and no air was in the tube after bleeding but when I start the truck the pedal goes to the floor and will only build up minor pressure. Did I miss a step or overlook something? Any ideas or suggestions are appreciated

 

Did you bleed the other 3 brakes as well, or just the offending corner?

It's likely you need a full bleed if that wasn't done. Starting in the back corner furthest from the master.

 

Oh yes I did rr, lr, rf, lf refilling the master cylinder after each wheel. There was normal pedal pressure before starting the truck then the pedal goes to the floor and there’s only minor pressure after pumping 5-6 times.

 

Just keep at it.

When I induce air to the system I do full strokes rather than holding with the bleeder open.

If you have loads of time, just leave the bleeders open and let them gravity bleed for a bit.

You'll get it, just takes a ton of work.

 

I ran through 2 large bottles of brake fluid and it looks like only clear fluid with no bubbles in the tubing now. I kept the master topped off after doing each wheel so I’m hoping that the master didn’t draw any air but it’s possible I guess. Thanks for the help!

 

Re-bleed, as others have suggested, furthest from MC to closest. Attach a length of hose to the caliper and send it to a small container to collect the used for fluid. Use ONLY BRAND NEW FLUID! If you didn't have to cut the foil off the bottle, then it's not new (dot fluid is hygroscopic, which means it absorbs water from the atmosphere, which contaminates your fluid and introduces air). Wear rubber gloves and eye protection, and avoid touching dot fluid, it's nasty stuff.

This is how I bleed:
Get a helper, and do the following. One person in the cab pumps the brake until it is firm, and then pushes hard to the floor, hold the pedal there, and shouts to the person at the caliper being bled, "open". The person at the caliper opens the bleeder, then says "open". Now, the person on the brake pedal feels that the pressure was let off and yells to the caliper person, "close". The person at the caliper closes the bleed port and says "closed". When "closed" is heard, the brake pedal person can release the pedal, and pump the brake again until firm.

Repeat those steps until no air is coming out of the caliper. A third person is helpful to keep an eye on the fluid reservoir.

Good luck

 

Thanks that’s exactly what I did with a helper. Everything went as I expected. I bleed the system with the engine off. Should I try it with the engine running?

 

Someone with a second gen will have to weigh in - but on my first gen, I do the brake work with the key on the off position with no issue. The only other thing I can think of, is that sometimes it's a good idea to completely push the pistons in by removing the pads and pushing the pistons back manually. This could knock loose a small air bubble hiding behind the back side of the piston, which even with brand new pads, is slightly pushed out of the caliper body when at rest. In extreme cases, like when chasing a problematic system or when replacing lines/calipers, etc, I'll bleed the system, then remove pads, pump until pistons are sticking out to the depth of the new pad's meat thickness, then manually push them back again, then replace pads and bleed again. Might be worth a shot.

 

That’s a good idea I’ll try that tomorrow thanks I appreciate the help!

 

Let me know how it goes

 

You replaced both calipers? Are the bleeder screws on top?

 

Yes the calipers had new bleeders installed

 

When you start the engine, now your getting the boosted power from the brake booster. Keep pumping with the engine running, it’ll build up and pedal feel will return. The first time I had this happen it puzzled me too. Once pedal feel returns, recheck & top off the master cylinder.

I’m not sure why you replaced the calipers. Were they leaking?

I like the yell open and close method Just_tombo. Whenever I do it it’s me who knows how and someone else who owns a foot.

Don’t forget to do the, bed in break in procedure, whatever it’s called.

 

Are the bleeder screws on top?

 

Are you pumping up the brakes then opening the bleeder?

 

My Haynes manual says to bleed with engine off, keys in the on position for vehicles with vsc and atrac. Something to do with keeping the channels open in the abs module
09+, I believe. I am having a similar issue after changing struts; even though all I did was unbolt and suspend the front calipers while the struts were out. If air gets into the master, it needs to be bled, which may be a dealer job. I do like a firm brake pedal.

 

Yes the bleeders are on the top. I chose to replace after I removed the wrong bolts and the caliper split open and the o rings inside the caliper came out. I opted to just replace instead of replacing o rings and risking more issues.
I get firm pedal after bleeding with the key off like I have in the past. After starting and pumping the pedal about 30-40 times I get only minor pressure stopping the pedal before it hits the floor. No leaks at the bleeders and the master fluid level stays constant when I pump the pedal with the engine running. I’ll try bleeding again tomorrow with my helper and the key in the on position.

Thanks again everyone for all the advice and help!!

 

It’s possible to put the right caliper on the left and left caliper on the right. Which would put the bleeders on the bottom leaving an air pocket at the top of the caliper.

I recently worked in a strange machine, the bleeder for the single disc brake mounted on the electric drive motor was a couple feet away from the master cylinder reservoir. So I was able to run clear tubing from the bleeder directly back into the reservoir. With the bleeder cracked open I pumped the pedal until no air bubbles came out. You could try something similar but run the tube into a bottle with a little clean fluid. When you press down on the pedal, fluid and air will push out and into the bottle. When the pedal comes up a little fluid will draw back up the tube. It will still take 2 people. One with a foot to pump, one to hold the tube in the bottle and watch for when the bubbles stop. The pressure will make the tube jump a bit

 

Some of the second gens have a vacuum booster, some are electric. I believe key on turns on the electric booster. If you bleed with the booster on, it’ll probably squirt out pretty hard.

If air got in the abs, it’s something the dealership and their special thing is needed to fix.

 

You seem have air in the ABS Unit. It needs techstream software to cycle the ABS Valves to get the air out.