rob_engineer

I may have added to the confusion. I think all or most brake fluids are synthetic, which are glycol based. Separate from that, but also synthetic is the silicone based fluid.

Mark Doiron

I'd avoid DOT 5 in any vehicle that's not specifically designed for it. There could be some compatibility problems with rubber and plastic components.

MikeRM

Dot 5 is used in the collector car world because it is silicon based and doesn't harm paint if spilled or leaks. It can be difficult to bleed as it can hold tiny air bubbles. It does not absorb water, so any moisture in the system will form water bubbles that can boil at height temperature and cause a soft pedal.

Dot 3 and 4 absorb moisture so water bubbles do not form if moisture enters the system.

ronjenx

DOT 3 and 4 will absorb moisture as you say, but that moisture contaminated fluid will turn to compressible vapor when the brakes get hot, resulting in a spongy pedal. That, and corrosion are two reasons it should be flushed every couple of years.

MikeRM

I think the theory is, moisture that enters the system is less harmful if it stays dissolved, rather than forming water bubbles or pockets. I would agree that any brake fluid contaminated with moisture should be flushed for the reasons Ronjenx stated.

JoeRif

Brake fluid change aside, why do So many Jeep brake systems fail? Ive changed my calipers, pads and rotors three times in three years and only put 8,000 miles on the Jeep over that span. No offroad or wreckless driving.

toolow262

So I pulled the wheel/tire, dropped the caliper and replaced pads (only on right rear thus far). I compressed the cylinder with little effort using a c-clamp and reassembled. This fixed the issue with the right rear brake being hung up, however after a <5 mile drive it was rather hot. The wheel was warmer than other 3 to the touch but bearable. But reaching through the wheel the rotor was hot after 1-2 seconds of contact whereas the other 3 were only warm and I could maintain contact with them. I don't experience any brake fade or sponginess, so I'm thinking maybe caliper though I didn't see anything wrong visually and didn't feel any binding when compressing the cylinder.

Side note... I've heard clicking in the center console under the shifters when starting the jeep, but noticed tonight the click happens every time I press the brake but only in park. Once in gear it either doesn't click or its to low to hear. Not sure if this is related.

rob_engineer

my 2012 JKU made it easily to 70,000 miles with zero maintenance in the brakes. I changed to pads front and rear at 70,000 as preventative maintenance. Rotors still looked great. Rear pads looked pretty horrible. I have manual trans which is easier on the brakes as you can use downshifting to help slow down.

rob_engineer

when I had heating issues with my RV brakes, I bought a cheap non contact infrared thermometer from harbor freight. Gives a digital readout and prevents you from burning your fingers.

toolow262

It's been a while, but I purchased a caliper, fluid, and hoses, so with shipping and waiting for a decent day in upstate NY it's been too long. Today I replaced the caliper and hose, and most of the fluid in the system, right away I was confident that I had rectified the problem. After a >5 mile drive the brake assembly was the same temp as the other 3 corners.

Also a note on the clicking I referenced in a previous post... it only happens in park, not sure if it is now noticeably louder due to age or if I've suddenly regained some hearing but it is the gear interlock relay (automatic transmission).