Severe Brake Fade after brand new pads and Rotors, and other brake gremlins.

[drome265]

Hello,

Recently purchased a 2014 3-door Euro Spec with about 65k KMs on the ODO. Knew the pads and rotors were EOL from the pre-purchase vehicle inspection, so ordered new EBC UZR slotted rotors and Yellowstuff pads to replace.

Strange phenomenon #1
After taking delivery of the car I went on a spirited drive down a mountain road (topping out around 100kmh/60mph). The brake pedal went to the floor the next day. There was however no fade during the spirited drive. From my experience on and off track, fade occurs immediately if the brake system is overwhelmed by heat. Why was there a delay in the boiling and air introduction into the lines?

Strange phenomenon #2
Car went to the mechanic for maintenance and addressing the brake issue. After installing the new rotors and pads, with brake fluid flush, went to bed in the brakes after about 400km of normal driving. After performing 3 100km/h - 0 stops (60mph - 0 in freedom units), there was SEVERE brake fade and I had to nurse the car to a parking lot to allow the system to cool. Pedal feel returned somewhat but not really to same as freshly bled.

Questions:

1. Are the stock brake sizes on this car not equipped to handle spirited driving? I run the same pads and rotors (stock size) on my NC Miata and they have not skipped a beat, even when pushed very very hard on the same mountain road.
2. What high temp brake fluid do you guys recommend? I usually go for Motul RBF600/660 but from just these 3 stops it looks like fluid alone isn't going to solve the problem.
3. My mechanic took a deep dive and said there was nothing else mechanically wrong apart from the obvious air in the lines. Could there be a different issue causing this problem?

Thanks everyone for their help.

 

[TyphoonFiST]

What type of Brake fluid was used? That's where i would start.....How was the system Bled and was the ABS controller Bled also?

 

[drome265]

What type of Brake fluid was used? That's where i would start.....How was the system Bled and was the ABS controller Bled also?

My mechanic has said it was regular street fluid, so probably not something with a very high boiling point. However it's the same stuff that went into my Miata and like I said that car has had zero brake problems, so what gives?

I can't imagine the brakes getting crazy hot after only 3 hard stops.

 

[FiestaSTdude]

The fiesta ST uses dot 4, so maybe check that dot 4 not dot 3 brake fluid was used in your car. Although I highly doubt that would cause your issue even if they were switched

 

[drome265]

The fiesta ST uses dot 4, so maybe check that dot 4 not dot 3 brake fluid was used in your car. Although I highly doubt that would cause your issue even if they were switched

My mechanic uses only DOT 4 fluid these days, but yeah I highly doubt that's the cause of the problem.

Do you guys think it's hardware related? Something failing up front in particular?

 

[akiraproject24]

When I did my rear brakes initially, I failed to line up the nubs on the outer pad backing plate with the groove in the piston face. Made the brakes feel odd and a bit soft. Could check that

 

[Dialcaliper]

Did your mechanic bleed the brakes the typical way (brake pedal, vacuum or pressure bleed), or did they bleed the ABS unit electronically? (Using an OBD tool or Forscan)

If the ABS unit was not done, there could still be air in the ABS unit, and when the air gets hot and expands, it can push fluid back up into the master cylinder between brake applications which will cause your pedal to go soft. It is different from fade and it doesn’t need to get hot enough to boil the fluid, which seems likely by how quickly it’s happening,

 

[cidsamuth]

Could be anything. But, the smart first move is a complete fluid flush and bleed with a quality Dot 4. If you plan to track, consider Motul or similar.

 

[the duke]

Master Cylinder failure?

 

[Capri to ST]

Master Cylinder failure?

I had the same thought, because this happened to my other car after a brake bleed. I had gotten some fancy new brake fluid and a mechanic had bled the system. When I got the car back, the pedal started going to the floor. I think the master cylinder was getting ready to fail, and the process of bleeding and having fluid pushed through was the last straw.

 

[drome265]

When I did my rear brakes initially, I failed to line up the nubs on the outer pad backing plate with the groove in the piston face. Made the brakes feel odd and a bit soft. Could check that

Thanks, will have a look at this when I get the chance.

 

[drome265]

Did your mechanic bleed the brakes the typical way (brake pedal, vacuum or pressure bleed), or did they bleed the ABS unit electronically? (Using an OBD tool or Forscan)

If the ABS unit was not done, there could still be air in the ABS unit, and when the air gets hot and expands, it can push fluid back up into the master cylinder between brake applications which will cause your pedal to go soft. It is different from fade and it doesn’t need to get hot enough to boil the fluid, which seems likely by how quickly it’s happening,

The ABS unit was not done, but my mechanic has used the eye test to check whether there ABS pump was still functioning. If the ABS pump fails, no fluid will exit at the faulty line. Will bring this up next time I take the car in.

 

[drome265]

I had the same thought, because this happened to my other car after a brake bleed. I had gotten some fancy new brake fluid and a mechanic had bled the system. When I got the car back, the pedal started going to the floor. I think the master cylinder was getting ready to fail, and the process of bleeding and having fluid pushed through was the last straw.

This is the next step, actually my mechanic named a new master cylinder as one of the fixes before even working on the car.

Any upgraded units you guys recommend, or Motorcraft OEM replacement is ok?

 

[drome265]

Could be anything. But, the smart first move is a complete fluid flush and bleed with a quality Dot 4. If you plan to track, consider Motul or similar.

This was already done when I had the rotors and pads changed. The issue is the severe fade that happened right afterwards with only 3 hard stops.

It's been a couple of days now and the brake has felt more normal. However, the car hasn't been pushed the same way as described in the OP. Do new pads/rotors take time to break in in terms of thermal performance?

Also noticed that the brakes get HOT on this car. On my other cars, after normal driving I don't feel the heat wafting off the rotors, but on the Fiesta it seems like the brakes are getting worked hard every drive (normal city driving).

 

[TyphoonFiST]

This was already done when I had the rotors and pads changed. The issue is the severe fade that happened right afterwards with only 3 hard stops.

It's been a couple of days now and the brake has felt more normal. However, the car hasn't been pushed the same way as described in the OP. Do new pads/rotors take time to break in in terms of thermal performance?

Also noticed that the brakes get HOT on this car. On my other cars, after normal driving I don't feel the heat wafting off the rotors, but on the Fiesta it seems like the brakes are getting worked hard every drive (normal city driving).

Pads and Rotors ideally should be bed in* I follow the bed in procedure by the Pad and rotor manufacturer and have NEVER encountered any issues. Most Bed in procedures have you drive with nice and smooth stops for about 50-100 miles. Then proceed to do a street bed in which is usually 6-10 Sops of 80-30mph but not completely stopping each time. Then when the final stop has been achieved you should be able to get out and smell the brake pads. That is good..then let the vehicle to completely cool down before driving again.

 

[cidsamuth]

It would be hard for us to truly know first your brakes are hotter than others based solely on your post. Is there a chance that the caliper is stuck and dragging the pads on the rotors?

 

[drome265]

It would be hard for us to truly know first your brakes are hotter than others based solely on your post. Is there a chance that the caliper is stuck and dragging the pads on the rotors?

It's possible but both fronts show the same behavior. I find it unlikely that both calipers would get stuck the same time. During driving I don't feel or hear significant resistance.

 

[drome265]

Pads and Rotors ideally should be bed in* I follow the bed in procedure by the Pad and rotor manufacturer and have NEVER encountered any issues. Most Bed in procedures have you drive with nice and smooth stops for about 50-100 miles. Then proceed to do a street bed in which is usually 6-10 Sops of 80-30mph but not completely stopping each time. Then when the final stop has been achieved you should be able to get out and smell the brake pads. That is good..then let the vehicle to completely cool down before driving again.

This is the exact same procedure where I'm having trouble.

The problem is at the street bed in step. At stop #3 the pedal travel has already doubled. I had to abort the bed in procedure and allow the brakes to cool.

 

[TyphoonFiST]

This is the exact same procedure where I'm having trouble.

The problem is at the street bed in step. At stop #3 the pedal travel has already doubled. I had to abort the bed in procedure and allow the brakes to cool.

Check rear pads not sitting in their Keyed spot on the pistons.

 

[drome265]

Check rear pads not sitting in their Keyed spot on the pistons.

Thanks for the tip!