Hello FTE, I have a 2005 FX4 114K and I am about to do a complete brake job. Calipers, Rotors and Pads and I was wondering if it makes sense to flush the system before I replace the calipers and then bleed after replacement? I don't believe the system has ever been flushed and my thinking to flush first is not to introduce old fluid in new calipers. Thought's?

 

I think that's an excellent idea for the very reason you stated.

 

I am about to change front brake rubber lines and flush fluid then put new rotors and new pads on fronts . I already removed old fluid from reservoir with turkey baster . I exercise the emerg brake on rear all the time to keep it working ..
I had a terrible time on first brake job ,the pistons were pushed out and absorbed moisture so after I pushed them back in they would intermittently stick over some weeks . The only fix was rebuilt calipers both sides .
So yes I think you are doing the right thing .

 

If you are flushing, then it won't matter. Old fluid will go straight out the bleeders. Just turkey baste the reservoir and refill before you replace the calipers and top off as needed from fluid loss (which should not be hardly any), then flush as normal. You are going to go through a lot of fluid anyways, no need to flush before hand. I am all for doing a job right, and doing it once, but when it comes to fluid flushes, that is like saying changing oil then letting it run then draining and refilling it again. Really not necessary. I just did ALL my fluids, and I know my brakes were never flushed either (new calipers, pads and rotors), and the fluid is crystal clear now. I went through about 3 or 4 bottles (bigger ones).

 

No it won't, the old fluid will first fill up and then circulate through the new calipers then finally go out the bleeder, depositing any contaminates along the way.

 

Psh, just did all four wheels pads, rotors, calipers this past weekend. Didn't bother to flush anything out. Just replaced and filled reservoir with new fluid as needed.

Flushing not a bad idea for peace of mind, but not necessary.

 

Agreed. Unless your brake fluid is black, it will flush just fine and contaminates depositing should not be an issue, as with any flush of fluids.

 

Thank you all for the feedback, I ended up flushing the system with a hand vacuum pump prior to replacing the calipers, rotors & pads.

I'm glad I did it because the color of the old fluid was like dirty dark green pond water vs the new clear fluid. I believe the fluid was 14 years and 114K miles old.

Also as mentioned, I did it for peace of mind.

PS: Although the vacuum pump did a good job of sucking out the fluid and filling the new calipers, I felt much more confident and the pedal felt better by having the wife pump the pedal for the final bleed routine.

 

I also use the e-brake all the time and I was surprised to find the passenger side cable unhooked and the pivoting assembly it's attached to completely rusted solid. Probably from the saltwater boat launches although its weird the drivers side looked and worked perfect.

 

I really hate it when people on a forum give the most expensive and arduous procedure as "the only right way to do it". It's easy to waste someone else's time and money. On this brake question, however, I err on the side of caution.
It isn't the little particles of rubber or whatever in the brake fluid that are dangerous, it's the dissolved water! That's right, the dissolved water lowers the boiling point of the brake fluid and when things get hot enough, the water flashes into steam. The steam takes up around 1100 TIMES the volume of the water. Bye bye brakes. I thought it was unlikely until it happened to me on a mountain pass in Montana. The brake pedal just went right to the floor, pumping the pedal did no good. Fortunately between shifting down and using the emergency brake I got the car stopped, but it was a wild ride.
That's the main reason to flush brake fluid. The other reason is to eliminate corrosion in the system. Again, the water comes out of solution when it gets cold enough and you have drops of water in the bottom of master cylinder bores and wheel cylinder bores, calipers too maybe. This leads to either failures or replacement and that means $$$.
R.

 

Brake fluid hygroscopic , means it attracts water . Don't use unsealed fluid . Flush system it should be clear . Dot 3 is not that expensive . Be careful washing engine ,cover master cly . Keep that parking brake lubed and working ,use it . Be vigilant if you are backing boat trailers in salt water, flush with soap and relube often . Better wash whole under side with soap, some car washes have this service during hurr salt water floods .

 

Plus one!
And the reason I flush brake fluid every couple of years is because any moisture in the fluid sits basically in the same spot in a brake line. Eventually it rusts the brake line from the inside out and makes a weak spot that will burst if you need to jump hard on the pedal. BTDT!