Brake pedal delay issue, sinks way down on first hit

[DSGWhippedSnake]

I've noticed over the past couple of days that the pedal seems to sink down more than usual on the first hit of the brakes. If I'm in traffic or going from stoplight to stoplight it's fine. But if I'm cruising for a little bit and then go to hit the brakes, the pedal sinks down noticeably more than usual on the first push but if I let off quick and hit the brakes again it's fine. I'm thinking maybe there's an air pocket in the lines somewhere? I haven't touched the brakes at all other than pulling the caliper off the bracket when I put my iso's back in. No lines have been touched etc. After I put them in is when I noticed the issue. The front calipers have been on and off the brackets many times for suspension/spring changes and adjustments with no issues at all, this is the first time this has happened. Any thoughts?

 

[DSG2NV03]

Any loss of fluid or anything? Maybe try a quick bleed to see if an air bubble moved from the removal of the caliper?

 

[Jimmysidecarr]

First look for leak evidence follow ALL the lines and hoses.

If no leaks bleed the brakes, including the master cylinder.

Still does it? Then it's likely an internal bleed inside a bad master cylinder.

 

[DSGWhippedSnake]

Any loss of fluid or anything? Maybe try a quick bleed to see if an air bubble moved from the removal of the caliper?

First look for leak evidence follow ALL the lines and hoses.

If no leaks bleed the brakes, including the master cylinder.

Still does it? Then it's likely an internal bleed inside a bad master cylinder.

From what I can see there are no leaks, and there has never been any loss of fluid. But tomorrow I'll put the car up in the air and take a better look and report back with my findings

 

[keith89]

Notice any change in the steering at all? Brake boosters are known to fail as well. I would try bleeding the master cylinder first though. When was the last brake fluid flush?

 

[jrgoffin]

Three words for you: Motive Power Bleeder...

 

[racebronco2]

Sounds like you have air in the system.

 

[SVT_Troy]

Which motive system are y'all going with because I want to buy one

 

[Silver TT]

Notice any change in the steering at all? Brake boosters are known to fail as well. I would try bleeding the master cylinder first though. When was the last brake fluid flush?

Can anyone explain the procedure to bleed the master cylinder?

 

[Blk04Snake]

Believe it or not it may be the hydrobooster system too. When your pedal is sinking check to see what the steering effort is like. If your steering fluid is breaking down or pump not making good pressure it's possible for this to happen. Seen it first hand on many 1.5 ton trucks at work with hydroboost brakes.

Also maybe one of your brake hoses is bad and expanding when you first hit the brakes

 

[jrgoffin]

Which motive system are y'all going with because I want to buy one

#0107 - works on many Ford vehicles. Once you use this you'll never waste your time doing it the old-school way again.

 

[DSGWhippedSnake]

Just put the car up in the air, no signs of leaks anywhere and no signs of any weak lines/hoses. Everything checks out ok as far as I can see :shrug:

Believe it or not it may be the hydrobooster system too. When your pedal is sinking check to see what the steering effort is like. If your steering fluid is breaking down or pump not making good pressure it's possible for this to happen. Seen it first hand on many 1.5 ton trucks at work with hydroboost brakes.

Also maybe one of your brake hoses is bad and expanding when you first hit the brakes

Notice any change in the steering at all? Brake boosters are known to fail as well. I would try bleeding the master cylinder first though. When was the last brake fluid flush?

I haven't noticed any difference in the steering when it happens, I'll be messing with the car today to test it some more. I have no idea when the last flush was. I've had the car for a year, it just turned 62k on the clock. I'm going to assume it was never changed but your guess is as good as mine :shrug:

Three words for you: Motive Power Bleeder...

Good to know. I'll be buying one of these if the problem persists :beer:

Sounds like you have air in the system.

Seems like it to me

Can anyone explain the procedure to bleed the master cylinder?

+1

 

[Anabolic]

i would buy a set of speed bleeders and bleed the entire system yourself with some DOT 5, check again and check the seals on the pistons in the calipers, check the master like jimmy said.

brakes hoses do colapse too..

so check to be sure you're getting good fluid at all corners maybe even upgrade brakes hoses wile you're at it.. they're inexpensive


ok guys and flame my advice!

 

[Silver TT]

Question on brake fluid as well. On this thread below some guys are saying to NOT run high end synthetic brake fluid because it is hydrophobic and will not mix with water. This means if you have any water anywhere in the system it will boil and cause air gaps in the lines or calipers.

Glycol based (non-synthetic) Dot 3 or 4 they are recommending as it is hydrophillic and will mix in with the small amount of water effectively reducing risk of that water ever doing any damage. Thoughts?

About to do a complete flush and bleed out the whole system and I just want to use the right fluids.

Changing brake fluid: how to/which one to get? - MustangForums.com

 

[Anabolic]

Question on brake fluid as well. On this thread below some guys are saying to NOT run high end synthetic brake fluid because it is hydrophobic and will not mix with water. This means if you have any water anywhere in the system it will boil and cause air gaps in the lines or calipers.

Glycol based (non-synthetic) Dot 3 or 4 they are recommending as it is hydrophillic and will mix in with the small amount of water effectively reducing risk of that water ever doing any damage. Thoughts?

About to do a complete flush and bleed out the whole system and I just want to use the right fluids.

Changing brake fluid: how to/which one to get? - MustangForums.com

you're not suppose to mix any brake parts with water ..... oke:

 

[jrgoffin]

i would buy a set of speed bleeders and bleed the entire system yourself with some DOT 5, check again and check the seals on the pistons in the calipers, check the master like jimmy said.

brakes hoses do colapse too..

so check to be sure you're getting good fluid at all corners maybe even upgrade brakes hoses wile you're at it.. they're inexpensive


ok guys and flame my advice!

Screw Speed-Bleeders, the last set I bought leaked like crazy. Get the POWER BLEEDER - it takes about 10 minutes to bleed the brakes and you will never screw with pedal pumping again.

Question on brake fluid as well. On this thread below some guys are saying to NOT run high end synthetic brake fluid because it is hydrophobic and will not mix with water. This means if you have any water anywhere in the system it will boil and cause air gaps in the lines or calipers.

Glycol based (non-synthetic) Dot 3 or 4 they are recommending as it is hydrophillic and will mix in with the small amount of water effectively reducing risk of that water ever doing any damage. Thoughts?

About to do a complete flush and bleed out the whole system and I just want to use the right fluids.

Changing brake fluid: how to/which one to get? - MustangForums.com

The Motorcraft brake fluid is fine for most guys, although the new formula isn't quite as good a the "old" stuff (boiling point reduced from 550 to 500). With the Power Bleeder, you can completely flush the system and replace all the fluid fast. It just doesn't get any easier.

 

[Anabolic]

iv got my speed bleeders on all four corners.. you probably bought some knock offs or installed the wrong ones in/got part #s confused... love the speed bleeders.. just open them up. pump pedal 3x then close repeat every 6months for fresh fluid.


dot 3 is what our cars call for..technically. ok ... usually import german cars are dot 4.. BUT dot 4 can be used it supercedes dot 3..
dot 5 is high temp race fluid..

NO BRAKE PARTS work with water especially fluid so none should get water involved..
don't 100% understand your question reguarding that.

 

[jrgoffin]

iv got my speed bleeders on all four corners.. you probably bought some knock offs or installed the wrong ones in/got part #s confused... love the speed bleeders.. just open them up. pump pedal 3x then close repeat every 6months for fresh fluid.

Hardly. Have used real Russell Speed Bleeders off and on for 20+ years, but their Q.C. appears to have gone down hill. Enjoy them, I'll stick with the power method.:bored:

 

[Anabolic]

Hardly. Have used real Russell Speed Bleeders off and on for 20+ years, but their Q.C. appears to have gone down hill. Enjoy them, I'll stick with the power method.:bored:

well that's probably why. russel only makes decent fuel hardware,
speedbleeder makes speedbleeders since 1997 and they work like a charm.
here's their website! http://www.speedbleeder.com/

and if you used them for apperently twenty years and they worked why bash them now :dancenana:

 

[racebronco2]

Can anyone explain the procedure to bleed the master cylinder?

Let the car sit overnight. Press on brake pedal, open up the bleeders at the master cylinder until just fluid comes out. Repeat as nessasary. Usually whenyou have bleed all the wheels and there still seems to be air in the system this precedure get the air out of the master cylinder. You must let the car sit overnight. With the abs you can try and bleed at each wheel and you will never get the air out because it gets trapped between the mc and the abs module.