Brakes and Midwest Cold....

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Aug 3, 2017
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So, as some of you may know, the Midwest is currently sitting smack in the middle of a polar vortex. 8" of snow followed by 15 below zero ambient temps reaching down to 35 below wind chills.

I'll start by giving credit where credit is due: My Jeep started an ran with little complaint, however this morning I was greeted by a bright red BRAKE warning light. The pedal felt fine, so I made my way to work. Come to find the master cylinder reservoir was just below the "MIN" mark... oh great.

I took a quick peek underneath and sure enough... BOTH front calipers are leaking from the piston seals. This is the THIRD set of reman's I've installed, and the issue always appears in sub-zero temps. The calipers came from OR, however I can't imagine they're any different than what I'd get from AZ or Napa. They're under warranty, of course, but c'mon.

I don't plan on dealing with the issue until it warms up, as I won't need the truck for the next few days. Color me annoyed, though!
 
I dodged a bullet yesterday, on the last day of work before Christmas break, I decided to bleed the rear brakes and service the fronts on my Legacy. I did a rear pad slap a few weeks ago and figured it can't hurt as I had some free time. I started by successfully cracking the rear bleeders sans heat and while those were dripping I took the LF caliper off to start the brake service. Well, it wasn't until I started reassembling the LF brakes that I realized what I had done. I had a helper pump the brakes to do the bleeding while the LF caliper was off! I don't know how the pistons didn't pop out. I thought you idiot, you know better, I grabbed my Channellocks and pushed them back in, and I know not to work on my car when the shop will be closed during the upcoming days, because something always goes wrong when you don't have access to the shop. It's -24c with the wind chill right now, this picture was taken 2 weeks ago.
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I'm always surprised with the number of vehicles on the side of the highway with steam(assuming)coming out from under the hood on really cold days. Cold days being 15F or less.
 
I'm always surprised with the number of vehicles on the side of the highway with steam(assuming)coming out from under the hood on really cold days. Cold days being 15F or less.

That's rarely due to overheating, and MUCH more likely to be some plastic cooling system component that went too quickly from -15 to +210.

Rubber hoses and metal cooling system components don't suffer from that issue. Metal castings can get colder than any human can withstand then be heated to unbearable temps without issue. Same goes for rubber hoses. Molded plastic housings bolted to metal engine castings? Good luck.

It’s not the Midwest that’s the issue.

It’s rebuilt calipers.

The cold just brings out the failures of cheap materials, lousy quality, and uncaring work.

I 75% agree with you. Rebuild calipers are definitely a gamble, however I install 5 pair a month easily and don't see this issue. My Jeep just seems to be... finnicky. When you live in MN your whole life, you quickly learn that there's "cold" and there's COLD. Most people would agree that +15 degrees is cold, which it is, however MINUS 15 degrees is a whole different ball game. That's a 30 degree difference, which to a vehicle (not to mention a human) makes a big difference.
 
That's rarely due to overheating, and MUCH more likely to be some plastic cooling system component that went too quickly from -15 to +210.

Rubber hoses and metal cooling system components don't suffer from that issue. Metal castings can get colder than any human can withstand then be heated to unbearable temps without issue. Same goes for rubber hoses. Molded plastic housings bolted to metal engine castings? Good luck.



I 75% agree with you. Rebuild calipers are definitely a gamble, however I install 5 pair a month easily and don't see this issue. My Jeep just seems to be... finnicky. When you live in MN your whole life, you quickly learn that there's "cold" and there's COLD. Most people would agree that +15 degrees is cold, which it is, however MINUS 15 degrees is a whole different ball game. That's a 30 degree difference, which to a vehicle (not to mention a human) makes a big difference.
MN seems like the warm South compared with my time in Winnipeg, but yes, extreme cold causes lots of failures.
 
Do they seal up in warmer temperatures?

I have never had an issue when ambient is over 0. Two years ago when I got the truck, it needed front calipers. I replaced them. but sure enough come December they leaked. I replaced them again, all was fine.

Last spring, the LF sprung a small leak, so I replaced it again. All fine.

That brings us to today. The once-replaced RF and twice replaced LF are both leaking, neither of which leaked some 5 days and 40 degrees ago.

I put many more miles on the truck in warmer temps than I do cold, which in theory should make no difference. The only thing I can think of is that the rebuilders just don't use piston seals that can stand up to serious sub-zero temps. As I said, the pedal feel has always been just fine, even at cold start. All I can come up with is that whatever material the piston seals are made of can't withstand prolonged sub-zero temperatures without shrinking which causes a tiny but steady leak over time.
 
MN seems like the warm South compared with my time in Winnipeg, but yes, extreme cold causes lots of failures.

Ha! While I'm sure you've experienced much worse, it can get plenty cold down here. The lowest actual ambient temperature I can recall in my 33 years was -25F. College days, driving my '94 Seville. I couldn't believe the thing started, to be honest.

I had a remote start with valet (aka police) mode, which allowed the car to stay running after removing the ignition key. I let the thing idle in the parking lot for 5 and a half hours that day!
 
I have never had an issue when ambient is over 0. Two years ago when I got the truck, it needed front calipers. I replaced them. but sure enough come December they leaked. I replaced them again, all was fine.

Last spring, the LF sprung a small leak, so I replaced it again. All fine.

That brings us to today. The once-replaced RF and twice replaced LF are both leaking, neither of which leaked some 5 days and 40 degrees ago.

I put many more miles on the truck in warmer temps than I do cold, which in theory should make no difference. The only thing I can think of is that the rebuilders just don't use piston seals that can stand up to serious sub-zero temps. As I said, the pedal feel has always been just fine, even at cold start. All I can come up with is that whatever material the piston seals are made of can't withstand prolonged sub-zero temperatures without shrinking which causes a tiny but steady leak over time.
I was wondering if the leaks stop when they warm up, thus not needing the replacement.

Lifetime replacement warranty on these?
 
I was wondering if the leaks stop when they warm up, thus not needing the replacement.

Lifetime replacement warranty on these?

Apologies, my response was long winded. Yes, they seal up just fine above 0 degrees.

They do have a lifetime warranty, I just have to dig up my paperwork.
 
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