Issue Under Heavy Braking - Toyota GR86, 86, FR-S and Subaru BRZ Forum & Owners Community

DustinS · 02-24-2017, 02:59 PM

Having an issue with the rear end of the car wanting to swing towards the driver side under heavy braking. I have to turn the wheel to the left to keep the car straight. It's enough that I have had passengers comment on it, and it's a little unsettling when trying to make it around a track/backroads. Alignment doesn't seem to have anything to do with the issue, but I am going to take it back in for another one as I just installed RB Fenders with new wheels/tires and want to double check everything. I haven't been able to track the issue down at all as everything seems fine. Does the same on stock struts and on the coilovers. Stickier tires seem to make the issue worse.

I did find that my driver side front pads are wearing unevenly for some reason (Running wilwood calipers. Inside pad is thicker than outside. Passenger side pads are about even). Cleaned up and checked the calipers and they seem to function fine, nothing seems stuck. Think the driver side caliper could be causing the issue? Maybe Uneven pad compounds front/rear?

Any help is appreciated.

G-Man · 02-24-2017, 03:14 PM

Quote:

Maybe Uneven pad compounds front/rear?

what pad compounds are you running?

DustinS · 02-24-2017, 03:20 PM

BP-20 and Stock rear haha. Always meant to change them, never did. Both need changed at this point.

Teseo · 02-24-2017, 03:32 PM

Maybe the other side its not braking at all. Worth to check

zc06_kisstherain · 02-24-2017, 03:37 PM

maybe front left pad not grabbing like passenger? so it steers to right and you need to make it correct it turning left

DustinS · 02-24-2017, 04:08 PM

Quote:

Originally Posted by zc06_kisstherain

maybe front left pad not grabbing like passenger? so it steers to right and you need to make it correct it turning left

That was my thought. Though everything seemed to move freely. I'll replace the pads and rebuild the calipers. If it is still happening, I will replace that caliper.

guybo · 02-24-2017, 04:12 PM

A lot of times that's an issue with a bad brake line. If it ever got pinched and damaged the poor flow will cause insufficient pressure on one side.

DustinS · 02-24-2017, 04:14 PM

That I didn't really think about. I'll check the lines really well, might just go ahead and replace them.

mrk1 · 02-25-2017, 08:05 PM

I found the rear of my car was on edge under heavy braking, can't say it favored a side though. When I upgraded from the torsen LSD to a clutch type the added torque on decel really locked down the back end, almost felt like I jumped up to a huge wide tire. It gave me confidence back for sure.

02-24-2017, 02:59 PM	#1
DustinS Senior Member Join Date: Apr 2014 Drives: 2013 Ultramarine FR-S Location: Springfield, MO Posts: 1,950 Thanks: 2,539 Thanked 1,423 Times in 806 Posts Mentioned: 31 Post(s)	Issue Under Heavy Braking Having an issue with the rear end of the car wanting to swing towards the driver side under heavy braking. I have to turn the wheel to the left to keep the car straight. It's enough that I have had passengers comment on it, and it's a little unsettling when trying to make it around a track/backroads. Alignment doesn't seem to have anything to do with the issue, but I am going to take it back in for another one as I just installed RB Fenders with new wheels/tires and want to double check everything. I haven't been able to track the issue down at all as everything seems fine. Does the same on stock struts and on the coilovers. Stickier tires seem to make the issue worse. I did find that my driver side front pads are wearing unevenly for some reason (Running wilwood calipers. Inside pad is thicker than outside. Passenger side pads are about even). Cleaned up and checked the calipers and they seem to function fine, nothing seems stuck. Think the driver side caliper could be causing the issue? Maybe Uneven pad compounds front/rear? Any help is appreciated. __________________

02-24-2017, 03:20 PM	#3
DustinS Senior Member Join Date: Apr 2014 Drives: 2013 Ultramarine FR-S Location: Springfield, MO Posts: 1,950 Thanks: 2,539 Thanked 1,423 Times in 806 Posts Mentioned: 31 Post(s)	BP-20 and Stock rear haha. Always meant to change them, never did. Both need changed at this point. __________________

02-24-2017, 04:14 PM	#8
DustinS Senior Member Join Date: Apr 2014 Drives: 2013 Ultramarine FR-S Location: Springfield, MO Posts: 1,950 Thanks: 2,539 Thanked 1,423 Times in 806 Posts Mentioned: 31 Post(s)	That I didn't really think about. I'll check the lines really well, might just go ahead and replace them. __________________

02-25-2017, 08:05 PM	#9
mrk1 Senior Member Join Date: Mar 2013 Drives: Sterling BRZ Ltd Location: New England Posts: 1,702 Thanks: 403 Thanked 1,389 Times in 671 Posts Mentioned: 21 Post(s)	I found the rear of my car was on edge under heavy braking, can't say it favored a side though. When I upgraded from the torsen LSD to a clutch type the added torque on decel really locked down the back end, almost felt like I jumped up to a huge wide tire. It gave me confidence back for sure. __________________ The Build Thread GT28RS - eBoost2 - 3.91 Final Drive - Supra LSD

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02-24-2017, 03:32 PM	#4
Teseo Senior Member Join Date: Jun 2014 Drives: frs Location: Gunsai Posts: 4,957 Thanks: 7,485 Thanked 2,981 Times in 1,803 Posts Mentioned: 23 Post(s)	Maybe the other side its not braking at all. Worth to check

02-24-2017, 04:12 PM	#7
guybo Huge E85 fan! Join Date: May 2016 Drives: 2016 Scion FRS Location: Tampa, FL, USA Posts: 1,850 Thanks: 539 Thanked 1,010 Times in 605 Posts Mentioned: 32 Post(s)	A lot of times that's an issue with a bad brake line. If it ever got pinched and damaged the poor flow will cause insufficient pressure on one side.

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