Feels like brakes are dragging...

Chandler

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Hi all,

I've posted this issue in a few other places and haven't gotten many replies - figured I'd post it here since this is a forum dedicated to the S197 platform. I have a 2012 GT 6-speed with 21K miles and a few mods - Airaid CAI, Bama 93 tune, LTH over-axle pipes, Roush axle-back exhaust, Ford Performance sway bars, Koni yellow adjustable struts and shocks, H&R Super Sport springs, J&M caster/camber plates, Stoptech Cryo rotors and G-loc R8 pads all the way around, and Nitto 555 G2s (stock size). I did a Track Night in America event at Road Atlanta at the end of last month, and during the last session, I got the "Service Advancetrac" warning and all the dash lights associated with the error. After some forum searching and digging I found out that the RR wheel speed sensor wire had gotten against the exhaust and melted, causing the error to pop up on hard RH turns. I had the car on my friend's lift the other day and we cut out the damaged portion and spliced the wires and tucked them up out of the way. The REAL issue I'm having is that since I got the warning during my session and the wires got burned, my car feels like the e-brake is on all the time or the brakes are dragging...except they're not. I've spent a few drives now closely monitoring the brakes and none are getting hotter than the others and I don't have any of the other symptoms of a dragging brake. I've got an email in to Bama so I can try to send them a datalog to rule out any engine issues, and the only other thing I can think that might be wrong is something in the clutch or that the ABS module itself is damaged. I know people have had issues where the clutch won't fully disengage, and that could be this issue, but I don't have the RPM increase with no speed increase that comes with a slipping clutch. I'm sort of at a loss here and very tired of my car feeling like it's pulling a trailer. Has anyone else had a similar issue? If you need any other info I'll be happy to provide it. FYI, I did do brakes before the TNiA event and couldn't push the rear caliper pistons in but it wound up being a tool issue - I couldn't get enough pressure to push inward on the piston. It would turn but not retract. At my friend's house the other day I was able to use the correct tool (thanks Advance Auto Parts) and pushed the pistons in with no problems. Everything brake-wise seems to function as it should.

-Mark
 

JEWC_Motorsports

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If you didn't solder the wires back together you will have an issue. The signal is low voltage and must be soldered.
 

Chandler

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Well...that could be my issue then. I did not solder them back together, we used butt connectors and heat shrink tubing to insulate. I'm not an electronics expert by any means, but is there a way to test the voltage at the wheel speed sensor connector so I can confirm before I tear it all out again? Could I compare driver's side to passenger's since the driver's side was intact?
 

JEWC_Motorsports

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Well...that could be my issue then. I did not solder them back together, we used butt connectors and heat shrink tubing to insulate. I'm not an electronics expert by any means, but is there a way to test the voltage at the wheel speed sensor connector so I can confirm before I tear it all out again? Could I compare driver's side to passenger's since the driver's side was intact?
Youd be better off pulling it apart, soldering, and shrink wrapping them again. Butt connectors are a bandaid but in this case an issue.
 

Juice

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There is a very simple test I do for brakes dragging. As I had them actually drag.
When stopped at a light with the slightest grade, car in neutral, I let go of the brakes. Car starts to roll, no drag.

Track days melt front caliper seals. I had a shattered piston after an event. Would not have known it if it wasnt for brakes dragging.
I had the caliper slides, the pins, rust and hang twice. Guess what the symptom is? lol
If your abs/advance track is now working, its not that repair you did thats an issue. (I have 2 good used rear abs sensors that came with my 8.8)
My car had one stuck ebrake cable when I bought it. The Ford dealer disconnected it on that side. So I had one wheel ebrake. Nice hub?
 

Chandler

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Thanks for the replies, all. @jewc75 you're right about the butt connectors being a Band-Aid, but I thought for this it would be OK, sort of an ignorance is bliss thing. I am going to take it apart again and solder the connection just so I can be sure. Again, not an expert but I would imagine the increased resistance in the circuit could cause it to activate the ABS and make it feel like the brakes are on, technically because they are?

@Juice I've done the grade test and the car rolls fine. I've had the rear brakes off since the track day and everything looked fine - I tested them before I removed the caliper and rotor and everything spun freely. I haven't had the front apart but I did spin each front wheel individually and nothing was stuck. I also had my friend get in and pump the brakes while I turned the wheels to make sure none of the hoses are collapsing.

Thanks again for replying. I'm finding very little about this issue but the fact that it just started happening after the wires burned is too coincidental for me.
 

Juice

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If the car rolls freely, what makes you feel the brakes are dragging?
 

Chandler

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I don’t necessarily think the brakes are dragging, I just don’t know how else to describe the feeling. It’s not like it’s down on power, but it feels almost like I’m pulling a trailer or like the e-brake is engaged, like I said in the first post.
 

Juice

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I don’t necessarily think the brakes are dragging, I just don’t know how else to describe the feeling. It’s not like it’s down on power, but it feels almost like I’m pulling a trailer or like the e-brake is engaged, like I said in the first post.
Gotcha.
One thing that comes to mind is if there is some type of an issue, sounds like you would notice a drop in fuel economy. But with such low miles, you may not know or care. lol
 

LarryJM

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Back brakes on the 2011-14 Mustangs with low use can freeze by just sitting. They can look new but will be as solid as a rock.
 

Chandler

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Yes, the back brakes have been verified and aren't sticking.

I think the point @jewc75 made is valid. If it's not getting the correct wave form from the wheel speed sensor then it could be making the TC system go crazy and apply the brakes. Separate but related, does anyone know of a good OBD scanner that will also read ABS module codes? My SCT X4 will not, apparently.
 

Juice

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Forscan + usb elm 327 with HS/MS can switch.
Software is free, no license needed to read/reset codes, and view live data from each module (where applicable)
Elm is about $25.
Need a windows laptop.

There are android and iphone versions of Forscan, those are not free and have limited capbility. No programming functions I believe. Never tried those.
 
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Chandler

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Thanks @Juice, I did some research and picked one up on Amazon. Maybe I can get some info from the system using this scanner and see if I can tell what's going on.
 

Juice

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I would look at live data from the abs module.
Select the 4 wheel speed channels.
Go for a drive. All 4 wheels should read the same going in a straight line.

Ps: Forscan is a great tool. If you need help with it, just ask.
 

Chandler

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Awesome, thanks for the offer. I may hit you up once it get it all set up so I can confirm what I’m looking at.
 

Chandler

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Hey all, wanted to give an update on this. I got the ELM327 in the mail yesterday and downloaded FORScan, and hooked it up to the car this morning. I ran the codes and came up with a stored ABS module code (RR wheel speed sensor, right where the wire was damaged), and PSCM code which I attributed to the ABS code, and one other Sync code. I cleared them all, went for a drive and it's fixed! I drove it for about half an hour, approximately 20 miles, checked the codes again and didn't have anything. While I was stopped I grabbed some lunch and let the car cool off, then drove 20 more mins home and checked it again, no codes! It feels as peppy as ever and stops on a dime now with the G-locs. @Juice thanks for the recommendation for this tool, I never would have been able to fix it without it. I didn't get into the live data analysis because the cable on the OBD tool is a little short and I was having trouble finding a comfortable place for the laptop - I have a USB extender at work that I'll bring home tomorrow and I'll do some more analysis this week just to make sure. But all-in-all I'm very pleased. @jewc75, I'm still going to rip out the butt connectors and solder the joint for my own sanity, but for right now I'm happy to have my car back to 100%. Thanks again!
 

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