Soft brake pedal feel

[texasboy21]

When I purchased my MS3 about 5K miles ago from a Ford dealership I negotiated that a brake service be performed on the car, as the pads had very little life left. The dealer replaced the pads and rotors on all four corners with what I was told were Focus ST parts. The stopping power felt fine, but not as firm as I would like, so I bleed the system using my Motive power bleeder (about 5K miles/7 months ago).

Now in that last 500-1000 miles the pedal feels soft, and takes more pedal input (throw) for the car to come to a stop. If I lightly stab the brakes, then press the pedal while coming to a stop it firms up to what I would consider normal, and the distance the pedal has to travel to stop the car is shortened.

I suspect the dealership may have installed regular Focus pads instead of the (presumably) more aggressive ST pads. Further, I am not confident in the dealer's brake work as both front calipers creak like crazy, leading me to believe they did not lubricate the caliper pins.

The brake fluid level is fine.
I have inspected several times for leaks and have not found any.
The pads and rotors were in fact replaced.

Could this simply be the pads giving me a soft pedal feel?

This is my second GenPu MS3, but my first one was purchased new. The first one purchased new had great initial bite, and the pedal throw was not as long coming to a stop.

Any input is appreciated. I want to feel confident in my brakes again!

[anavrinIV]

This sounds exactly like air in your lines.

[mituc]

Replace the brake fluid and bleed the lines properly. Replace ALL brake pads and rotors at the same time if you suspect something is wrong. Brakes stop the car. Not being able to accelerate fast will not harm you, but not being able to stop may.
Maybe the ford dealer installed those new good pads (let's assume they were good) on worn rotors. You may not even want to know, just replace everything.

[texasboy21]

Originally Posted by mituc Replace the brake fluid and bleed the lines properly. Replace ALL brake pads and rotors at the same time if you suspect something is wrong. Brakes stop the car. Not being able to accelerate fast will not harm you, but not being able to stop may. Maybe the ford dealer installed those new good pads (let's assume they were good) on worn rotors. You may not even want to know, just replace everything.

The rotors and pads were both replaced, this is confirmed becuase I watched them do it - I just didnt check the part number on the pads that were installed.

The system (four corners and clutch) has been bled with a power bleeder properly.

Originally Posted by anavrinIV This sounds exactly like air in your lines.

Wouldnt this only incur if the system was 'opened'? Since the last time I bled the brakes nothing has been touched.

[mituc]

Originally Posted by texasboy21 The rotors and pads were both replaced, this is confirmed becuase I watched them do it - I just didnt check the part number on the pads that were installed. The system (four corners and clutch) has been bled with a power bleeder properly. .

The rotors or pads don't have anything to do with the soft/spongy pedal. Air/gas bubbles in the brake lines do.

[texasboy21]

Originally Posted by mituc The rotors or pads don't have anything to do with the soft/spongy pedal. Air/gas bubbles in the brake lines do.

I don’t doubt that the soft pedal feel can be related to the air in the lines, however in my case the pedal began to feel soft nearly 4000 miles after any brake work was performed. I would think that if I had air in the lines it would have become apparent immediately following the service. None the less, I plan on bleeding the brakes again this weekend to see if it resolves my issue.

I also plan on greasing the caliper guide pins to get rid of the awful creaking, however I may hold off on this as I am contemplating upgrading the pads to a more aggressive compound (I have a pile of go fast parts waiting to be installed once I get the brakes sorted). My working theory is that the calipers are not clamping down on the rotor as well as they should due to increased friction on the guide pins. Not sure how likely this is; its just a thought.

[texasboy21]

Originally Posted by mituc The rotors or pads don't have anything to do with the soft/spongy pedal. Air/gas bubbles in the brake lines do.

I wanted to show you this article Car and Driver did on various brake pads on a MX-5. It shows quantified evidence that different pads require more pedal force as well as pedal travel.

Performance Brake Pads Compared: Hawk HPS, Hawk HP Plus, EBC Yellowstuff | Car and Driver Blog

[mituc]

More pedal force to get the same braking force is different than the pedal feel. Bleed your lines.

[frothy]

Doing an aftermarket part comparison between the MS3 and Focus ST shows different part #s for front pads. The rears seem to match up. So, are the pads they put on your car even compatible? Did the dealership provide an invoice with part #s ?

[ALPINEST4RS]

Try doing a few ABS stops and see if the pedal rises up. Gravel road. Air gets trapped in the ABS module and its impossible to bleed out of the valving mechanism. After a few stops the pedal should rise.

[mituc]

This is what probably happened actually. There was air in the ABS module and was bled out after one-two more hard stops and now that air is somewhere else. I had the same problem at some point so I kind of know.

[texasboy21]

Wanted to update this thread. I bleed the brakes once again with a motive power bleeder, and the initial bleeding from the clutch bleeder valve had quite a bit of bubbles. The calipers did not appear to have any air in them.

After bleeding the system the pedal has firmed up quite a bit. I am still unsure how air entered the system over 1K miles after bleeding the the first time, but for now all is good.

I appreciate the replies and help offered by those in the thread.

[mituc]

The ABS pump is hard to bleed, or impossible. Usually when the brake fluid boils and needs to be replaced you need to do a few ABS brake stops to get it out, and bleed the brakes again.

Also, if the mechanic bled the brakes improperly (one of the common mistakes is not to top up quickly enough which results into a lot of air sucked into the system including the ABS pump) or not enough then may also cause this problem to appear after a while.

Whenever it happens go bleed the lines again. Usually it takes about 600-700ml of brake fluid for a complete change, so you have at least 300ml left for one or even two bleeds.

[texasboy21]

Bumping this thread..

The brakes are back to feeling soft. What could be going on that could allow air to enter the system? When I bled the brakes most recently, the only air bubbles were from the clutch bleeder.

[roguemazda]

unless they got dirt in the brake fluid and its not sealing properly, meaning bits are floating about in the system?? or your master cylinder is failing or there's a very small leak some where

[mituc]

Originally Posted by texasboy21 Bumping this thread.. The brakes are back to feeling soft. What could be going on that could allow air to enter the system? When I bled the brakes most recently, the only air bubbles were from the clutch bleeder.

If you didn't boil the brake fluid in the meanwhile when bleed the system again and top it up. Then see where that goes. There's a chance you had some air in the ABS pump and hopefully it went all out, finally.

[texasboy21]

Originally Posted by mituc If you didn't boil the brake fluid in the meanwhile when bleed the system again and top it up. Then see where that goes.

Not sure what you are saying.

I will bleed the system again. One thing to note, the brake pedal stiffens up (feels right) when braking with the clutch engaged. Seeing as I had some air bubbles come out of the clutch bleeder screw last time, I think is safe to presume the clutch is somehow involved. Thoughts?

[mituc]

Originally Posted by texasboy21 Not sure what you are saying. I will bleed the system again. One thing to note, the brake pedal stiffens up (feels right) when braking with the clutch engaged. Seeing as I had some air bubbles come out of the clutch bleeder screw last time, I think is safe to presume the clutch is somehow involved. Thoughts?

The clutch and brake fluid circuits meet only at the top of the brake fluid fill hole, they have nothing in common otherwise and the exchange of fluid between the two under normal conditions is non-existent.
However, if the fluid boils you may see some exchange.

[texasboy21]

Originally Posted by mituc The clutch and brake fluid circuits meet only at the top of the brake fluid fill hole, they have nothing in common otherwise and the exchange of fluid between the two under normal conditions is non-existent. However, if the fluid boils you may see some exchange.

The fluid has not boiled - no track days or hard driving, just to and from work + errands. I did have one "panic stop" but at a low speed ~10mph. The pedal felt better afterwards, but within a few days it became as soft as before.

Sound like air in the ABS?

[mituc]

Originally Posted by texasboy21 Sound like air in the ABS?

Yes, it does. Do a panic stop just before you enter the shop for bleeding the brakes. Replacing the brake lines may also be a good idea if you didn't do that in the last few years. I used to get a spongy pedal with GoodRidge stainless lines until I replaced them with the StopTech lines.

[texasboy21]

Bumping this thread again. I think I found the culprit. My clutch slave bleeder screw seems to be leaking even when tightened.

So the question is, can I replace just the bleeder valve, or is the entire slave toast?

MazdaSpeed Forums Presents: YouTube

MazdaSpeed Forums Presents: YouTube

[texasboy21]

Bump - clutch bleeder looks to be the culprit - replace the bleeder valve?

Does anyone know the thread pitch and size of the bleeder?

[Tomas]

Yes replace bleeder valve.
No that will not help your soggy brake pedal feel.

[texasboy21]

Originally Posted by Tomas Yes replace bleeder valve. No that will not help your soggy brake pedal feel.

What WILL help the soggy pedal feel? I have tested, inspected, and bleed the system countless times. Its good for a week or two, then back to mush.

[mituc]

Then probably it draws air through from somewhere. How old are your brake lines?

[texasboy21]

Originally Posted by mituc Then probably it draws air through from somewhere. How old are your brake lines?

Stock lines - car was built in late 2012.

[ChaunceyM]

Check for leaks inside the calipers, too. I know a Focus ST guy that had fluid leaking around the piston seals which lead to him sucking air into the system.

[texasboy21]

Originally Posted by ChaunceyM Check for leaks inside the calipers, too. I know a Focus ST guy that had fluid leaking around the piston seals which lead to him sucking air into the system.

I have inspected the brakes numerous time, but will take a closer look at the calipers.

There has to be something allowing air to get in, but without fluid escaping.

[sheston]

Have you looked to see if the brake bleeders are doing the same thing as the clutch? I assume that was torqued down correctly

I'll also add that I tried one of those vacuum bleeders and it's really hard to see what's going on. It will pull air thru the bleeder screw and look like air in the system. Finally did it the old fashioned way with some help from a pedal pusher

[texasboy21]

Originally Posted by sheston Have you looked to see if the brake bleeders are doing the same thing as the clutch? I assume that was torqued down correctly I'll also add that I tried one of those vacuum bleeders and it's really hard to see what's going on. It will pull air thru the bleeder screw and look like air in the system. Finally did it the old fashioned way with some help from a pedal pusher

I have not noticed the same thing from the brake calipers.

I am not using a vacuum bleeder, I am using a power (pressure) bleeder. It attaches to the brake fluid reservoir and pressurizes the system to force the air and fluid out of the bleeder. There is no way to push air back through the bleeder with the pressure bleeder.

https://www.motiveproducts.com/colle...ropean-bleeder

[roguemazda]

Throw that thing in the bin and get a friend who can take simple instructions ,in bleeding the brakes in the traditional way

[ihamzeh]

have you fixed the issue ?? i have a 2013 mazda 3, and i have soft brake pedal, i bled the system twice, and when i bled it, the pedal were firm for 2 weeks, and then it got soft again, and as i said i bled it twice with the same issue coming back in 2 weeks, any suggestions?

[Db09ms3]

Take it to a mechanic

[mituc]

Originally Posted by ihamzeh have you fixed the issue ?? i have a 2013 mazda 3, and i have soft brake pedal, i bled the system twice, and when i bled it, the pedal were firm for 2 weeks, and then it got soft again, and as i said i bled it twice with the same issue coming back in 2 weeks, any suggestions?

You have a leak. You need to find where that leak is. Usually it's the lines. Usually...