Brake Pedal goes 2 inches from floor before engaging

[Steven Caplinger]

Good day to you all. I’m gonna try this because I’ve run out of options on what to do. I have an issue with my brakes where the pedal goes to about 2 inches from the floor before the brakes engage to slow the car. I have a 2010 Toyota Corolla, S 1.8L 1798CC L4 FI VIN: L-2ZRFE engine. This is what I have done so far…..

· Replaced Master Cylinder

· Replaced back brake shoes

· Rear Drums, smooth

· Replaced rear brake cylinders

· Replaced Brake Booster

· Replaced Vacuum hoses from booster to engine

· Bled brake lines, 5 times per wheel

Each time I drive, it takes almost the full travel to approximately 2 inches from the floor before the brakes engage to slow car. When car is turned off, brakes feel solid, takes effort to press down.

NOTE: Front brakes pads, rotors and calipers are all in new(ish) condition.

I have done the reverse, hitting the brakes, pulling the emergency brake to make sure the back brakes are adjusted. When back brakes were replaced, drum was placed on and there was little friction when turning. I also found a gravel parking lot and slammed on the brakes to initiate the ABS system.

I am gonna try a re-bleed once more tonight, but any other advice would be greatly appreciated as I have exhausted any and all resources in determining the cause of this issue.

NOTE 2: When pressing the brake, I hear a very shot hiss coming from the underside of the hood. I cannot pinpoint it directly, but it is only when the engine is on and the brake pedal is pushed.

 

[CorollaTom]

Sounds like you have essentially rebuilt almost all your entire brake system so it is not hard to envision your frustration. At this point, I suggest you carefully recheck the replacement items (e.g., brake booster, master cylinder, rear brake cylinders) - did you use new, brand-name parts versus rebuilt or used (junk-yard) parts? Also, every now and then a new part will be found to be faulty. (If the brakes feel solid when the car is just turned off, then the booster is probably okay; this leaves the master cylinder and air in the lines as suspects though you sound like you have ruled them out.)

Finally, when you bled the brake lines, did you use an assistant to depress the brake pedal or did you use one of the "one man" bleeding procedures which can introduce air back into the line if one is not very, very careful? In spite of what you hear, the two person method is the better way to keep air out during bleeding.

If I guessed, I'd say to consider replacing the brake cylinder again, with a new brand-name type (return the other one if you bought it). With my 91 Camry, I had a similar problem as yours, then after a few weeks it sank to the floor. Scary. I replaced the master cylinder with a "rebuilt" OEM part from Cardone but the problem returned after a few trips. It was hard for me to imagine that a Cardone product could be faulty. After great frustration and difficulty in stopping, I replaced my rebuilt unit with a new (not rebuilt) Raybestos part (made in Taiwan!) which worked perfectly and that was two years ago.

 

[CorollaTom]

Just another thought occurred to me about the installing of a replacement master cylinder that was not mentioned in the original posting. The master cylinder must be correctly bled before it is installed - this is not the same as bleeding the brake lines. There are several videos on YouTube on how to bleed this part before it is installed and there are one or two on bleeding it after it is installed. The instructions included with the my master cylinders on how to bleed them were quite different from the videos but turned out to be correct in my case. If the master cylinder bleeding procedure is not done or is not done correctly, air will be left in the master cylinder (that line bleeding cannot easily purge) and "spongy" brake pedal will most probably result.

 

[John K]

Hi I'm here to learn and problem solve. I have almost the same vehicle with same engine, Pontiac Vibe 2010 1.8 L.

Just did rear brakes, new calipers, rotors and pads. Bled entire system at all 4 wheels using 2 man system. Can get pressure at brake pedal with engine off, but on starting engine it drops to within an inch (likely less) of the floor.

If I hold the brake pedal down fully, shut off the engine and wait 30 seconds then pump the brake 2 - 4 times the system re-presuures.

Once I've got pressure, I can hold the pedal firmly and it maintains pressure - doesn't sink back down. This makes me think that the master cyclinder is good.

I wonder if it might be the check valve on the master cylinder. I think the system creates vacuum assist to help pull the brake pedal down, but I don't understand fully the role of the check valve and maintaining pressure on both sides of the brake booster diaphram.

PS - Here is where I might have screwed up. Normally the brake bleeding procedure at each wheel is press and hold the brake pedal. Open bleed valve at caliper, bleed a second or two and then close bleed valve and finally release the brakes. Then repeat until no more bubbles.

It was getting dark and we were a hurry and I think for a few iterations we got it wrong. Opening bleed valve with the brake up - pushing pedal and and then closing valve.

Appreciate any ideas - Again I think it maybe the check valve or if not that then the brake booster. If I take out the check valve and test it for airflow - will it reseal with the old grommet?

Thanks, John

 

[CorollaTom]

John,
First, did you have this problem before you installed new rear brakes, new calipers, rotors and pads?

If proper re-bleeding does not solve the problem and you can see no leaks or loss of fluid in the brake fluid reservoir, then the master cylinder is high on the suspect list. If you do replace the master cylinder yourself, remember that it requires a separate bleeding of its own before installing.

Let us know how things turn out.
Tom

 

[John K]

No problems before installing new calipers, rotors, pads.

Thanks for input. Will try another bleed all the way around.

 

[John K]

No problems before installing new calipers, rotors, pads.

Thanks for input. Will try another bleed all the way around.

Hi again Tom (and others)
I just went out and tried to test the check valve on the brake booster, as per instructions found here >>> itstillruns.
then test-brake-booster-check-valve.

After removing the hose from the check valve where it attaches to engine. I had to insert a small flexible tube to reach the hose to blow into it. I found that I could not blow or suck through the hose and check valve. According the link posted just above, it means my check valve is not up to snuff.

I couldn't find one at my local parts store or either a GM (because it's a vibe with Toyota Corolla / Matrix 1.8 L engine) or local Toyota dealer. GM dealer searched and found part discontinued, Toyota Canada wanted $79 (Can) for it but it would take two weeks to come from US as all Canadian warehouses were out.

Found one on line for $35 (Can) plus shipping of $21 to get it within 3 business days. I did this yesterday because I suspected the check valve.
My reasoning was since I can get pressure with engine off 1) master cylinder is ok - and 2) vacuum brake booster works to bring pedal close to floor with extra vacuum pressure.

Since I have to wait for parts I will re-bleed in case extra vacuum pressure is compressing air locked in the system.

Question - Might the check valve be okay - just seems to fail because I have notgot enough pressure from my lungs?

 

[CorollaTom]

John,
I could not access the link you cited, but I surmised that it required a person to blow into the booster or suck air from it. Either way, it would be surprising that any person would have lungs powerful enough to simulate enough vacuum (or atmospheric pressure) in a brake booster and hold it long enough to functionally test it.

However, on YouTube there is a valid in-car test easily performed using the right foot. Just search for "HARD Brake Pedal - How to check if your BRAKE BOOSTER is GOOD or BAD". This is a simple, but quite valid demonstration that functionally tests the booster, including the check valve. Perhaps you might want to try this before replacing the check valve.

If you ascertain the brake booster is okay per the YouTube test, then you might re-consider the master brake cylinder again.

Tom

 

[Sunamer]

I was able to fix the problem by adjusting rear brakes with a screwdriver. Basically, you adjust them so that wheels just have a bit of drag and do not spin freely (no parking brake) engaged. That removed that “slack” from the pedal.

Watch this video starting 7:10 mark. You will see how to adjust the brakes.