I've noticed when I ascend a mountain or high altitude pass that my brakes get really soft and less effective if I don't periodically pump them to keep pressure. I am running upgraded rotors and pads, but was wondering what I need to upgrade to eliminate that issue? I'd like to not have to worry about it, and just have them work consistently.
Brake fade at high altitude
- Thread starter JK Rocker
- Start date
No, I did not bleed the brakes when I swapped the rotors and pads. I didn't know that was necessary. I am running the stock/factory brake fluid.
TRLJNKY
New member
Ive driven anything from sea level to about 10k feet and havnt noticed any difference in my brake pedal. Something aint right imo. Maybe I need to pay more attention to the feel on my end though too. Hope you figure this out.
sipafz
Caught the Bug
It's not necessary to bleed the brakes because you replaced the rotors and pads. Resetting the caliper piston will not induce air into the system. Altitude has nothing to do with your brake performance. Heat or air in the line can diminish performance. Tire performance might be a factor (sliding). Has anyone other than you touched the brakes since 08?
jeeeep
Hooked
Bleeding isn't necessary but pushing the calipers in to get the new pads on may have pushed some of the fluid out.
Also depending on how old the fluid is that's in there may play a factor in the ability to do its job.
I tend to be overly cautious about changing fluids regularly with the way I use my jeep, one of those being brakes and will bleed the brakes just to get some new fluid in there when replacing brake pads .
Also depending on how old the fluid is that's in there may play a factor in the ability to do its job.
I tend to be overly cautious about changing fluids regularly with the way I use my jeep, one of those being brakes and will bleed the brakes just to get some new fluid in there when replacing brake pads .
Coop
Caught the Bug
^^^^This^^^^
MurderedJK
Member
If its been awhile at least flush the lines.
Brake fluid is hygroscopic meaning that it will absorb water. Brake fluid is not recirculated throughout the system on it own. When you pour new fluid in at the res that will not reach the brake lines since the old fluid is taking up that space. As brake fluid brakes down it will start to boil (higher elevations the faster fluids heat up) and the fluid will start to absorb water at a higher rate. If its been awhile I would top off the res and do a really simple brake line flush (just the lines). Can be done in in about an our using a "one man bleeder." At every brake job I at least drain the brake line fluid to recirculate the fluid in the system.
Brake fluid is hygroscopic meaning that it will absorb water. Brake fluid is not recirculated throughout the system on it own. When you pour new fluid in at the res that will not reach the brake lines since the old fluid is taking up that space. As brake fluid brakes down it will start to boil (higher elevations the faster fluids heat up) and the fluid will start to absorb water at a higher rate. If its been awhile I would top off the res and do a really simple brake line flush (just the lines). Can be done in in about an our using a "one man bleeder." At every brake job I at least drain the brake line fluid to recirculate the fluid in the system.
Bustedback
Member
Not a bad idea to flush the brake fluid every two years. The stuff does wear out and performance diminishes.
cozdude
Guy with a Red 2-Door
It's actually recommended by the manufacture that you do a brake system fluid flush every 3 years because of the hydrscopic abilities of brake fluid. No one ever does it tho lol.
QuicksilverJK
Caught the Bug
Just running with an idea here so bear with me. The smallest amount of air in the system, possibly not enough to really notice at lower elevations will expand as atmospheric pressure decreases (causing a larger volume of trapped air) I would do a full brake fluid flush before anything else. Air/ water compresses. Brake fluid doesn't. Like I said this is just my brain trying to come up with a logical explanation and not based on any first hand experience.
swampdog
New member
cav♤fighter;740717 said:
No way dude, it's a legit fact. You should see what can happen to brake fluid in high stress situations. I used to road race a Yamaha R6 racebike and we would completely drain and refill new fluid at least two times a year (keep in mind, the race bike was luck to get 1,000 miles a year). We ran Motul RBF600 (super high performance DOT4 fluid), and as the time approached for the flush, you could notice brake fade much earlier in a race.
Keeping ALL of the fluids fresh in your vehicles is a no brainer and WILL make it last longer.
Zstairlessone
New member
I though that brake systems were sealed... Otherwise we would be changing fluid all the time and would have brake fluid all over under the hood. Altitude and changing atmospheric pressure should have no effect, and brake fluid has to get EXTREMELY hot to boil over. Chances are you notice it in the mountains due to the extended usage, try flushing your brake system - replacing the fluid with new DOT4 fluid. Start with the passenger side rear, driver's side rear, passenger front then driver front.
swampdog
New member
I don't think anyone said it boiled over, and yes, they are sealed.
cozdude
Guy with a Red 2-Door
Do not switch to dot4. The seals in the system will not be able to take the different chemical compound of the fluid. You will be replacing the master cylinder if you do
WJCO
Meme King
I've heard people say that they've had no problem using either, but from what I've been taught, I would agree with cozdude. Do not use any fluid that the cap does not have printed on it.