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Hey guys, wondering if someone can fill me in on the proper brake bleed procedure.
06 IS250 AWD.
Had to replace both front calipers due to them being seized and can't seem to get a pedal.
We used the software to run the ABS pump to bleed, ran 2 quarts through and still no pedal.
Swapped out the master cylinder and went through the process again but still have no pedal. No leaks of any kind. We can get a firm pedal with the vehicle off but as soon as we start it up the pedal is on the floor. The brakes barely stop the vehicle at idle.
I'm obviously missing something.... any advice is appreciated.
Are you sure u slowly floor and release the brake pedal while bleeding even you got firm feel?
My first time bleeding brake.... I thought I got firm feel as well but actually I should go even further.
Thank you, I've bled 1000+ cars, not sure why this one wants to be difficult. I've relined vehicles, replaced ABS, M/C, Calipers..... not sure why this vehicle won't give me a pedal. We'll bleed again tonight and use the abs pump software.
Thanks again, if there is anything else you can think of let me know.
Double check MC to brake booster depth. If the push rod from the booster ends up depressing MC when it is bolted down, it seals the reservoir partially and thus doesn't get a full volume of fluid to move the pistons at the calipers.
In short the piston can look the same but you need to measure the depth and verify the piston is not being depressed when tightened down.
One can do this by installing a dab of putty or clay in the MC cup. Carefully bolt MC down completely. DO NOT press brake pedal. Unbolt MC and inspect clay. If it is smashed clear through to the piston cup, the plunger from the booster is too long and needs shortening. All it needs a small gap like 0.5 to 0.75mm.
Then bench bleed MC
Install connecting lines.
Connect tubing to RR and manually bleed having helper press pedal down with bleeder open. Seal bleeder. Lift pedal. Wait a second. Press pedal down and open bleeder. **ALWAYS seal the bleeder before the pedal is allowed to come up.
Move to LR. Repeat.
Move to RF. Repeat.
Move to LF. Repeat.
For added firmness, hold pressure ( pedal down ) and Tap upwards on each caliper with a block of hardwood. This will knock small air bubbles free allowing them to combine into larger bubbles and travel up to the bleeder and escape when the bleeder is opened. Repeat 3x per caliper. << assuming you have pressure now.
Last little bit, if just doing maintenance bleeding, grab 100ml industrial luer lok syringe and 3 feet of silicone tubing. Suck the MC dry before adding new fluid and mixing. The flush will go much faster.
Thanks again for the input. We had the problem before we replaced the M/C.
We have the software to run the abs pump, we moved more than 2 quarts of fluid through the system which in my experience is excessive to say the least.
I have no pedal, goes to the floor and barely keeps the car stopped at idle.
I've escalated it to a Toyota Technician for a second opinion.
I'll update the thread when I determine the issue but this is strange for sure.
I've bled, built, rebuilt, relined entire braking systems and have not had this trouble. The calipers replaced show 0 signs of leaking, perfectly dry.
Had a guy drop the bottles sealing foil into the reservoir and it later wreaked havoc down stream.
Something to keep in mind.
PS if bench bleeding will not build pressure at the MC (no car involved) you have a problem at the MC.
Abstract but what if putting the pedal to floor ruined the aged MC? What if new MC is defective? Bench bleed to rule out. It should build pressure.
Had a guy drop the bottles sealing foil into the reservoir and it later wreaked havoc down stream.
Something to keep in mind.
PS if bench bleeding will not build pressure at the MC (no car involved) you have a problem at the MC.
Abstract but what if putting the pedal to floor ruined the aged MC? What if new MC is defective? Bench bleed to rule out. It should build pressure.
Agreed. We bench bled the new cylinder and it was clear. We ran the abs pump to put 2 qts through the system. 0 air coming out. It does pressurize enough to stop the vehicle but just not right as if air is still trapped in it. The pedal feels too soft all the way through the travel position, it is engaging the master cylinder too.
I got a Toyota tech on it. It is obviously something that I am overlooking. The only thing I can think of is the new calipers but I would see some wetness at the leaking point. Bone dry. 0 loss of fluid
Did the MC build pressure on the bench? That is what I am asking. Rarely something we test for. I get that.
As for pedal travel, as long as the caliper is floating, you could have wood pads in there and build pressure. Less so if caliper is stuck and flexing something.
We had pressure on the bench bleed. We bled it very slowly on the bench, capped it off and had pressure to a point where we couldn't even press the plunger in. I have someone looking at it now so we'll see what they find.
It doesn't make sense and I am eager to find out what I am missing.
06-09-19, 10:55 AM
Brake Bleeding Procedure.
