I've been about 5000 miles out west over the last two weeks and a couple of minor problems have shown themselves.
First off. 2002 E350 5.4 extended body. I recently put new front pads on it, not sure which pads until I get home but I usually buy the 'better' pads from Autozone or Advance. I don't think I put the 'super, heavy duty' pads on the van, but probably should've given the weight I'm loaded with when traveling.
I have never flushed out the fluid, the van has 130k on it.
The symptom is that when descending long or steep grades, after the brakes get good and hot, I get severe wobble from the front end on brake pedal application, like a severely warped rotor. This goes away after the brakes cool, and I am able to slow the van, no brake fade, but it certainly freaks the family out. What's going on? My fluid is fine, and is not boiling over or anything, I have stopped immediately to check things out when this has happened. So far, it has only happened twice, but is not something I will just live with.
Also, just to rule this out before people jump to conclusions and assume i'm an idiot (at least that's what I would do), I am pretty mechanically inclined and I drive an 18 wheeler for a living. I'm quite familiar with how to get a vehicle stopped even with a brake problem. I know how to use brakes properly, pulsing and without steady pressure, and I haven't at all felt like I was out of control or put anyone at risk. This is certainly not something I'm going to ignore though.

 

If the rotors have been replaced in the past with Steel rotors instead of Cast Iron ones and you used (Full Metalic) brake pad with Steel rotors they will warp like crazy when hot! They will settle down after a while and get real noisey with low speed braking. Let the Steel vs Cast Iron battle begin...................

 

Well I may get schooled on this. I'm not sure what the PO did rotor wise, but I have only replaced the pads once, and I'm not sure until I get home which pads I used.
Are you saying the steel ones will warp when hot and then actually smooth out when they cool and have no permanent effects, until they get hot again?
If that is possible, I think it may be my problem, because I can't for the life of me explain this wobbly feeling for anything other than a severely warped rotor, but they smooth out.
Weird.

 

Anyone? I'm still clueless on this problem.

Thx

 

Could be corrosion or pad deposits on the rotors. This would most certainly be the case if it van sits a lot, or if you had gotten the brakes hot, and stopped somewhere for a while while holding the brakes. I would have them turned by an on vehicle lathe at a decent brake shop, and hand them some nice, decent grade new pads. I like yellowstuff for vehicles that are HEAVY.