Long Brake Pedal Travel vs Soft Brakes

S

stever1000

New member
I have been trying to track down a brake issue since I bought my 2000 4runner limited.

With the car running and at a stop, I can apply the brakes and the pedal sinks as I press it down, there doesn't seem to be any resistance until near the end of the travel. I can pump the brakes and it doesn't sink as far.

Similarly, while driving I can come to a stop, but it feels like the pedal travels too far before there is brake power. If I pump the brakes a few times (in anticipation of needing to stop responsively) the pedal travel appears to be less before I get brake action.

I don't think there is air in the main lines because once the pedal travels far enough, the brakes work really well.

I did the brake booster check as per the hanes manual and it checks in good. With the car off I can pump the pedal and after 3 presses the pedal is firm and doesn't move.

I have replaced the following:

master cylinder (OEM from camelback)
flexible brake hoses (front are SS, back is rubber)
Complete brake fluid flush
New bleeders (speed bleeders to make bleeding easier)
Adjusted rear brakes (twice, first time I overadjusted and got back fuel economy with only slightly better response)

I originally thought it was the master cylinder because the previous owner replaced the brakes himself and I want to point my finger at him pushing the pedal too far and effecting the seal. So I replaced the master cylnder... it seemed to help a bit but the pedal still sinks to the floor...

I'm tempted to buy a Motive power bleeder to see if I can bleed the ABS unit to see if it makes any difference

Any thoughts on what I can do? I've read a lot of threads and it seems various people replace different things but it's never consistently the same fix...
 
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I'm going through the same exact thing (see a few threads down). I have a hunch it is air stuck in the ABS module as well. I can't seem to find any information on how to bleed it.

This is probably a bad idea, but I'm thinking about maybe cracking open the bleeder screws on the wheels very slightly and doing a ton of skids on some loose gravel or sand :pound:. If there is air in the ABS, that should move the air pocket into the brake lines. From there, I should be able to just bleed it regularly.
 
m0ist said:
I'm going through the same exact thing (see a few threads down). I have a hunch it is air stuck in the ABS module as well. I can't seem to find any information on how to bleed it.

This is probably a bad idea, but I'm thinking about maybe cracking open the bleeder screws on the wheels very slightly and doing a ton of skids on some loose gravel or sand :pound:. If there is air in the ABS, that should move the air pocket into the brake lines. From there, I should be able to just bleed it regularly.
Click to expand...

This sounds like a terrible idea... Never drive with the bleeders open.

OP - I know you said the rear brakes were adjusted, but for me 9 out of 10 times it is the rear brakes when the pedal firms up after a pump. Might want to search around for proper adjustment procedure. Either way I would vote for getting a motive power bleeder. It is one of the best tool purchases I have made.
 
it sounds to me like you have several problems.

have you considered taking it to someone who does this type of work professionally?


to your actual problems, did you bench bleed the MC prior to hooking up the lines? if yes, are you certain you got all the air out?

the next thing is the rear brakes. you said you adjusted them several times, but, I have a feeling they still aren't adjusted correctly.

assuming the MC, and system is bled and working properly, the rear DRUM brakes are singularly responsible for pedal travel. the fact you can pump the pedal a few times and bring it up makes me think there is still an issue with the rear adjustment.
 
m0ist said:
This is probably a bad idea, but I'm thinking about maybe cracking open the bleeder screws on the wheels very slightly and doing a ton of skids on some loose gravel or sand .
Click to expand...

Hope your life insurance is up to date.

:popcorn: :lookout:
 
nevada said:
it sounds to me like you have several problems.

have you considered taking it to someone who does this type of work professionally?


to your actual problems, did you bench bleed the MC prior to hooking up the lines? if yes, are you certain you got all the air out?

the next thing is the rear brakes. you said you adjusted them several times, but, I have a feeling they still aren't adjusted correctly.

assuming the MC, and system is bled and working properly, the rear DRUM brakes are singularly responsible for pedal travel. the fact you can pump the pedal a few times and bring it up makes me think there is still an issue with the rear adjustment.
Click to expand...

I bench bled the master cylinder using a kit and clear hose. The M/C was perfectly flat and I tapped the body as well as declined it (to untrap any air in high spots). I bled several times each side as well as together until there were no bubbles in the lines. Even the tiniest little bubble I bled out. The resivoir was always full so that air couldn't get sucked in. Bleeding took a long time because the plunger can only move so much fluid so I carefully and slowly pressed it, held it, and very slowly released so the bubbles could travel upwards and out

If any air was introduced it was at the outlet of the mastercylinder which would get pushed into the hardlines anyway. I would highly highly doubt there is air in my M/C as I did it very carefully following directions

The brakelines were drained since the master cylinder was removed for a few nights, so bleeding the brakes took a long time until all the bubbles were removed. I used speed bleeders with clear hose into clean fluid so that the small chance the speed bleeder malfunctioned, I wouldn't get air back into the line.

There sure could be human error, so I will look at getting a motive bleeder to cross that off my list...

I will re-adjust the rear brakes. I'm sure they could be part of the culprit, especially reading that pumping the brakes moves the cylinder closer so that makes sense why pumping would increase the brake action. The more I read, the more I think they could be a factor.

I also adjusted my parking brake without removing the spring so the autoajuster may not be working or could be hindering my adjustment
 
Last edited:
Ok so the only fix is slamming on the brakes to activate the ABS, bleed and repeat OR get the dealership to activate the ABS with the special tool?
 
stever1000 said:
Would this also get the air out of the ABS module?
Click to expand...



If the ABS was never activated then to me there isn't any air in it if it wasn't active with the system open.

The pressure bleeder is the end all for bleeding brake systems. Screw the speed bleeders. I've used it on two different vehicles with brake lines rusted through and a empty master cylinder. Never needed to do a bench bleed using a pressure bleeder.

Plus it totally eliminates the need for two people. If your pre pumping your brakes to me you still got air.


Sent from my iPhone using Tapatalk
 
Ok I will breakdown and get the pressure bleeder - fingers crossed this improves things some more along with checking the rear brake adjustment another time
 
19963.4lsr5 said:
Remember to pump it up to the 15psi recommended pressure.


Sent from my iPhone using Tapatalk
Click to expand...

Thanks - I hope to tackle this soon. The bleeder is sitting in the 4runner begging to be used, I just moved and can't work on the vehicle in the new parkade, so I need to wait for a dry day to do it on the street.
 
em

stever1000 said:
Thanks - I hope to tackle this soon. The bleeder is sitting in the 4runner begging to be used, I just moved and can't work on the vehicle in the new parkade, so I need to wait for a dry day to do it on the street.
Click to expand...



I'm having a similar issue...did you use the pressure bleeder and did it fix your problem?
 
Other folks have said it....if your brake pedal travels too far but firms up, this is typically a rear brake adjustment issue. If the pedal is soft but pumps up, it is usually a hydraulic issue - air in the lines or bad MC.

Buckaroo
 
Buckaroo said:
Other folks have said it....if your brake pedal travels too far but firms up, this is typically a rear brake adjustment issue. If the pedal is soft but pumps up, it is usually a hydraulic issue - air in the lines or bad MC.

Buckaroo
Click to expand...

I’m at a loss on mine
I had the back brakes adjusted and they firmed up more, but the pedal is still soft and has some travel before the brakes engage. I replaced the MC and bled the brakes with the motive bleeder at 15 psi. I also engaged the ABS when it snowed hoping to get air out from there if it exists

Still don’t have a firm, responsive pedal
 
I have had the same issue on my 4runner for a while now as well. New MC (ADVICS) and 5 bleeding cycles with Mityvac. I mean I ran like 54oz of fluid through the thing. Did pads and rotors in the front in January.

When I was inspecting the rear brakes last week I found that my rear brakes are soaked in gear oil from the axle seals. That has now taken the priority for repairs, but also is likely playing a role in the way the brakes feel so I'm hoping I will see a difference after the seals are fixed and new rear brakes installed/adjusted.

How do you bleed the ABS module?
 
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