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Discussion Starter · #1 ·
Lately I've noticed that when i brake moderate between 45 mph highway speeds my car pulls to the left. If i am hands off the wheel to diagnose, my steering wheel then turns to the right, moving my car to the right.
2013 ST2, only brake upgrade is Hawk HPS pads. I am running 17" Blizzaks on aftermarket rims. Cold tire pressures set equal all positions. It did not seem, or i did not notice this, when my summer setup was on.

If I am in neutral, it seems worse than if I am braking in a gear.

Alignment check was good, all brake hardware torqued to spec.

I measured rotor and caliper temps the other day, the left rear was slightly higher than the right rear (maybe 20+ degrees) however the front caliper and rotor (measured at same spot both sides) was around 50. I know Ford uses the brakes to mitigate torque steer, however getting the brakes warmed up was simply braking off the highway, no hard acceleration.

I've been chasing this for about a month now, and my next attempt to fix will be greasing the caliper slide pins (just did it before winter).

Has anyone else experienced this?
 

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I would start with cleaning your rotors with some 800+grit sandpaper. Sand to scuff, both sides. Just get a scuff on there.
Then also measure pads to compare left side to the right side to see if there is uneven wear.

Outside of that, do a proper bedding of your brakes.
https://www.tirerack.com/brakes/tech/techpage.jsp?techid=85

Bedding will reseat the pads properly, and may address any contamination issues you may have had, causing this issue. This is the cheapest, easiest thing you can do at the moment. You can even opt to install the old pads, or a cheap set of auto-part generic ceramic pads; and see if the issue changes, or goes away.

Outside of that, it could be a sticking caliper which will need a rebuild/replacement, or some other hydraulic issue. Which will require more time, and a lot more potential cost.
 

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Discussion Starter · #4 ·
so some backstory.

September 2016 I did a HPDE at Mid-Ohio, forgot to put it in track mode first outing, ended up with 600°F rotors and probably about that temp at the caliper too (had paint on them rated to 500°F and it turned black). Got the car home, took apart the front brakes, greased the slide pins / pad contact areas, sanded the rotors, scuffed the pads, and bedded them back in. Everything was GTG after that.

About a month or so back i drove down a flooded road, through 6-8" water. No issues after that (though for sure my horn would go out but it still works).

So I either think I got some water in the RF caliper, or whatever damage i could have done on track finally caused the caliper for malfunction.

Since I've taken everything apart and cleaned it several times, I am about to just go with the bigger rotors off a newer gen ST, 2 new calipers, and stainless lines.

I'll try one more time pulling rotors and pads, scuffing, and bedding. Also will try putting summer rubber back on, however braking was straight when i first put the WS80's on.

Thanks for the info!
 

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If you melted the seals on the pistons, which happens when things get too hot, you could have a caliper that is not functioning 100%, thus you can rebuild those calipers, putting in new seals, which is really easy to do, maybe 1hour tops per caliper to perform. Or buy new reman calipers, or buy new calipers.

Which is why I suggested the cheap/easy route before spending a bunch of money on new parts ;-)
 

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Check your caliper slide pins and make sure the caliper can slide on them smoothly. This is common symptom of slide pins being seized so clamping force on rotor isn't the same on both sides of the car. I see that you mention you greased them, make sure both sides slide equally as easy.

If it's not this issue then it's an issue with hydraulic pressure not being the same at each caliper piston. This could be do to damaged caliper piston seals, damaged brake line, ect.

Brakes are relatively easy in this sense so diagnosing and fixing the problem shouldn't be too bad.
 

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OK, no one else is saying it; Ouch! 600 degrees!!! And OUCH, burned paint!

That's all.
 

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OK, no one else is saying it; Ouch! 600 degrees!!! And OUCH, burned paint!

That's all.
If you track a car, you never worry about the color of your calipers (Function over form). Thus why most racing calipers are either black/silver/Nickle coated or anodized. All the Subaru's and their fancy gold brembo calipers turned to doodoo brown after a handful of events.
 

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If you track a car, you never worry about the color of your calipers (Function over form). Thus why most racing calipers are either black/silver/Nickle coated or anodized. All the Subaru's and their fancy gold brembo calipers turned to doodoo brown after a handful of events.
Yup, Back in the EVO world we would call them Brownbos.
 

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Discussion Starter · #10 ·
So i replaced both front calipers, went with the 2014.5+ larger rotors (had them zinc coated so hopefully the vane's don't rust as bad), brackets, and stainless lines all around. Running Hawk HP+ pads with titanium shims. Motul 600 fluid.

Had issues bleeding the brakes, getting the RR to start with a power bleeder. So in a late night fit of rage i pumped the sh!t out of the brake pedal to start getting fluid back there so i could start getting the air out. I was planning on replacing all the fluid with Motul so I wasn't worried about the amount i would have to bleed.

So, everything back together, bedded the pads per instructions (6-8 medium speed passes, braking to slow but not stop, then 6-8 high speed). Brakes bite amazingly hard, even with Blizzak WS-80's on. Way more mu even with cold brakes compared to HPS.

Anyway, I have another question / potential issue.

The car still feels like it may be pulling to the left. Tire pressures are set to placard + a few PSI because marshmallow like snow tires. It feels like it pulls a little left, but if i brake shortly after or on a different road it feels straight.

My question is should I look at the master cylinder now? It's not leaking at all, however in my frustration in pumping the brakes I am wondering if i could have damaged the master seal?
The car has 40k on it and I've never had the reservoir even open, so I am not really concerned that I had any dirt in there, just throwing out if anyone has any experience damaging a master seal and what symptoms point that direction.

Is it possible to fail a master cylinder seal by pumping the brakes after a caliper / brake line change?
 

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If your seal was broken, it would be leaking. I had issues with the Motul brake fluid too. Changing to Redline fluid solved the problem. I have no idea why using Motul felt like the master cylinder was leaking...
 

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2013 early production? Had the same type of problems but ended up having to do nothing with the brakes or alignment. There were problems with the internal torque sensors in the PCM (wiring shorts....Ford's electrical work is priceless) and other problems related to very early model epas.

Essentially the entire steering rack had to be replaced since the problem is not serviceable. It's a long frustrating story dealing with Ford on this when I was under warranty. There are two class action lawsuits last I read against Ford with the early epas. I had to get a lawyer involved myself to get it fixed under warranty.

If you've exhausted all the brake troubleshooting, then you may be one of the few early focus production models with this nifty feature. You either live with the odd behavior or replace the rack which is not cheap out of warranty.

The troubleshooting is really difficult because it mimics problems more rationally associated with brakes, alignment, etc.

I hope you don't have the epas issue.
 

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So i replaced both front calipers, went with the 2014.5+ larger rotors (had them zinc coated so hopefully the vane's don't rust as bad), brackets, and stainless lines all around. Running Hawk HP+ pads with titanium shims. Motul 600 fluid.

Had issues bleeding the brakes, getting the RR to start with a power bleeder. So in a late night fit of rage i pumped the sh!t out of the brake pedal to start getting fluid back there so i could start getting the air out. I was planning on replacing all the fluid with Motul so I wasn't worried about the amount i would have to bleed.

So, everything back together, bedded the pads per instructions (6-8 medium speed passes, braking to slow but not stop, then 6-8 high speed). Brakes bite amazingly hard, even with Blizzak WS-80's on. Way more mu even with cold brakes compared to HPS.

Anyway, I have another question / potential issue.

The car still feels like it may be pulling to the left. Tire pressures are set to placard + a few PSI because marshmallow like snow tires. It feels like it pulls a little left, but if i brake shortly after or on a different road it feels straight.

My question is should I look at the master cylinder now? It's not leaking at all, however in my frustration in pumping the brakes I am wondering if i could have damaged the master seal?
The car has 40k on it and I've never had the reservoir even open, so I am not really concerned that I had any dirt in there, just throwing out if anyone has any experience damaging a master seal and what symptoms point that direction.

Is it possible to fail a master cylinder seal by pumping the brakes after a caliper / brake line change?
If you're paranoid that the calipers aren't getting equal pressure, pick yourself up 2 brake pressure gauges. Thread them onto both front caliper bleeders and start your car. Hold the brake pedal steady and have another person check each caliper's pressure gauge. Don't use a fuel pressure gauge or trans pressure gauge, it must be brake pressure gauge as your brake system uses brake pressure in excess of 1500 psi.
 
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