Front calipers locked up after pistons melted
05-12-2011, 12:56 PM
#1
Burning Brakes
Thread Starter
Front calipers locked up after pistons melted
on Tuesday @ Lime Rock.
Calipers and rotors are/were OEM but pads are Carbotech 1521's. SS lines, Castrol SRF, Quantum ducts, Kuhmo Ecsta XS tires on CCW C-140s. Set up worked just fine @ same track in mid-April. Temp was about 15 - 20 degrees warmer this week though. Pads are not glazed over. Thought upgrades would prevent exactly what happened.
Had OEM pads without any of the above upgrades last year with no issues (5 track days). Not braking any harder. In fact, as experience grows, braking is becoming more smooth, less hard jabs.
Need recommendations balancing cost with effectiveness to prevent repeat.
Thanks
Calipers and rotors are/were OEM but pads are Carbotech 1521's. SS lines, Castrol SRF, Quantum ducts, Kuhmo Ecsta XS tires on CCW C-140s. Set up worked just fine @ same track in mid-April. Temp was about 15 - 20 degrees warmer this week though. Pads are not glazed over. Thought upgrades would prevent exactly what happened.
Had OEM pads without any of the above upgrades last year with no issues (5 track days). Not braking any harder. In fact, as experience grows, braking is becoming more smooth, less hard jabs.
Need recommendations balancing cost with effectiveness to prevent repeat.
Thanks
05-12-2011, 01:12 PM
#2
Team Owner
DRM stainless steel pistons is the easiest and cheapest. What lap times were you doing to melt the pistons? Stock pads won't make enough heat. If you melted the pistons your calipers can't be in good shape probably spread.
Last edited by John Shiels; 05-12-2011 at 01:15 PM.
05-12-2011, 01:40 PM
#3
Team Owner
I melted a rear piston last year and ended up tossing the caliper too.
Way too much heat and had a heck of a time getting the piston out.
Way too much heat and had a heck of a time getting the piston out.
05-12-2011, 02:14 PM
#5
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on Tuesday @ Lime Rock.
Calipers and rotors are/were OEM but pads are Carbotech 1521's. SS lines, Castrol SRF, Quantum ducts, Kuhmo Ecsta XS tires on CCW C-140s. Set up worked just fine @ same track in mid-April. Temp was about 15 - 20 degrees warmer this week though. Pads are not glazed over. Thought upgrades would prevent exactly what happened.
Had OEM pads without any of the above upgrades last year with no issues (5 track days). Not braking any harder. In fact, as experience grows, braking is becoming more smooth, less hard jabs.
Need recommendations balancing cost with effectiveness to prevent repeat.
Thanks
Calipers and rotors are/were OEM but pads are Carbotech 1521's. SS lines, Castrol SRF, Quantum ducts, Kuhmo Ecsta XS tires on CCW C-140s. Set up worked just fine @ same track in mid-April. Temp was about 15 - 20 degrees warmer this week though. Pads are not glazed over. Thought upgrades would prevent exactly what happened.
Had OEM pads without any of the above upgrades last year with no issues (5 track days). Not braking any harder. In fact, as experience grows, braking is becoming more smooth, less hard jabs.
Need recommendations balancing cost with effectiveness to prevent repeat.
Thanks
This year I updated to stainless pistons in all 4 calipers, added stainless lines, added Quantum ducts and didn't have any real issues using XP10s in the front and XP8s in the rear other than the pedal getting a little spongy during one session. A couple of laps at reduced speed gave me a hard pedal again.
If you update to stainless pistons make sure you get the Centric Seal Lubricant along with the seals. Don't bother installing the dust boots if you are going to run pads that run hotter than the 1521s.
How do you like those tires and what sizes are you using?
Bill
05-12-2011, 02:20 PM
#6
Safety Car
Geeze... I've melted a few dust boots but never the caliper piston. I do run Titanium pad shims up front and they keep everything good to go... don't melt dust boots anymore.
05-12-2011, 02:25 PM
#7
Team Owner
I ran my Z for a season and a half at WGI on stock calipers using Cobalt CSR pads, Hawk HP+ pads without any piston issues. OEM pads probably reach there max coefficient of friction a couple hundred degrees less than the Carbotechs you used.
This year I updated to stainless pistons in all 4 calipers, added stainless lines, added Quantum ducts and didn't have any real issues using XP10s in the front and XP8s in the rear other than the pedal getting a little spongy during one session. A couple of laps at reduced speed gave me a hard pedal again.
If you update to stainless pistons make sure you get the Centric Seal Lubricant along with the seals. Don't bother installing the dust boots if you are going to run pads that run hotter than the 1521s.
How do you like those tires and what sizes are you using?
Bill
This year I updated to stainless pistons in all 4 calipers, added stainless lines, added Quantum ducts and didn't have any real issues using XP10s in the front and XP8s in the rear other than the pedal getting a little spongy during one session. A couple of laps at reduced speed gave me a hard pedal again.
If you update to stainless pistons make sure you get the Centric Seal Lubricant along with the seals. Don't bother installing the dust boots if you are going to run pads that run hotter than the 1521s.
How do you like those tires and what sizes are you using?
Bill
05-12-2011, 03:18 PM
#8
Racer
I ran my Z for a season and a half at WGI on stock calipers using Cobalt CSR pads, Hawk HP+ pads without any piston issues. OEM pads probably reach there max coefficient of friction a couple hundred degrees less than the Carbotechs you used.
This year I updated to stainless pistons in all 4 calipers, added stainless lines, added Quantum ducts and didn't have any real issues using XP10s in the front and XP8s in the rear other than the pedal getting a little spongy during one session. A couple of laps at reduced speed gave me a hard pedal again.
If you update to stainless pistons make sure you get the Centric Seal Lubricant along with the seals. Don't bother installing the dust boots if you are going to run pads that run hotter than the 1521s.
How do you like those tires and what sizes are you using?
Bill
This year I updated to stainless pistons in all 4 calipers, added stainless lines, added Quantum ducts and didn't have any real issues using XP10s in the front and XP8s in the rear other than the pedal getting a little spongy during one session. A couple of laps at reduced speed gave me a hard pedal again.
If you update to stainless pistons make sure you get the Centric Seal Lubricant along with the seals. Don't bother installing the dust boots if you are going to run pads that run hotter than the 1521s.
How do you like those tires and what sizes are you using?
Bill
05-12-2011, 03:33 PM
#9
Team Owner
05-12-2011, 06:12 PM
#10
Burning Brakes
Thread Starter
Tires were a major improvement but I was coming from run flats. 275/35/18s up front on 18x11 wheels. 345/30/19s out back on 19x12s. Kept 18/19 split after long search of options for street tires which I plan on running for a while. Added width in rear was very noticeable going on to No Name straight - really bit well. Didn't really notice an increase an understeer. Might need a few more days to get a better sense there.
05-12-2011, 10:04 PM
#11
Burning Brakes
Thread Starter
DRM stainless steel pistons is the easiest and cheapest.
- Yep, that's what I was thinking.
What lap times were you doing to melt the pistons?
- Don't know, not set up with data acquisition yet. I ran well within my run group but with < 10 days, I am no Mario Andretti. Definitely not fast enough to cause the problem. Something else I haven't figured out was the cause.
Stock pads won't make enough heat.
- Pads were Carbo 1521s which don't operate significantly higher than OEM. 900 degrees max I think. They are street pads. They shouldn't have caused the problem.
If you melted the pistons your calipers can't be in good shape probably spread.
- Yep, that's what I was thinking.
What lap times were you doing to melt the pistons?
- Don't know, not set up with data acquisition yet. I ran well within my run group but with < 10 days, I am no Mario Andretti. Definitely not fast enough to cause the problem. Something else I haven't figured out was the cause.
Stock pads won't make enough heat.
- Pads were Carbo 1521s which don't operate significantly higher than OEM. 900 degrees max I think. They are street pads. They shouldn't have caused the problem.
If you melted the pistons your calipers can't be in good shape probably spread.
05-12-2011, 10:09 PM
#12
Burning Brakes
Thread Starter
I am surprised as well. Mods were made to prevent brake issues and no way was the braking that I was doing should have come anywhere near melting the pistons. Ran completely stock last year @ LRP 3 or 4 times without issue. Doesn't add up.
05-12-2011, 10:52 PM
#13
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I didn't use the lube the first time around and the pistons were a PIA to get in. I thought I was going to break my 10 inch C Clamp it was taking so much force to get the pistons in. As it was a couple of seals tore and I did the whole thing over again. The lube made things much easier. I was able to push most of the pistons in with my arthritic thumbs.
Centric Part No. 500.10000 made a huge difference.
Bill
Centric Part No. 500.10000 made a huge difference.
Bill
05-13-2011, 08:06 AM
#15
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FYI I've never melted a stock piston and believe me I've tried
05-13-2011, 09:03 AM
#17
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Bill
05-13-2011, 10:25 AM
#18
Race Director
then that would seem to leave a caliper dragging.. if hes driving smooth, not on the brakes much on a high speed momentum course with brake cooling upgrades and SRF fluid.. it seems to point to something mechanical.
05-13-2011, 02:29 PM
#20
Burning Brakes
Thread Starter
Piston must have stuck, certainly didn't have foot on brakes. There is only 1 spot on Lime Rock where hard braking is necessary, i.e. the end of the main straight.