Look up Death Wobble it's a common issue with Ford and Dodge. I had this with my 06 F250 and it turned out to be a 5 lbs difference in tire pressure. Scared the crap out of me and called AAA, the driver look over the front end checked tire pressure and said that was the problem I had no more issues with it after that but I always check now. There are other reasons for the wobble.

 

This is something different. The death wobble isn't restricted to when you are braking under load.

 

5lbs too high or too low?

 

Death wobble is just a name given for reference to a common problem with any solid front end suspension and was something to look up to get some ideas. There are so many things that can cause this that I don't think anybody will be able diagnose this particular problem without laying hands on the truck themselves. The only thing I will say with confidence it's not warped rotors you can feel that in your foot under any breaking for sure if you have the trailer brakes adjusted properly IMO. I don't no jack about suspensions but brakes I get. Also I know of a few guys that have found no issues with the front ends but took a suggestion of installing air bags and that eliminated there issues.

 

To low on the left side.

 

I knew that could happen on the old iron rotors under hard use, but my buddies over on the road racing circuit were telling me they solved it by chamfering the holes on both sides of the rotor...also the early rotors had the holes drilled at right angles to the rotor (the cheap and quick way) then they started drilling at a slight angle along with the chamfering solved the problem???? Have you heard of any of this? I could be way out of date on my info...

 

Warped rotors will not always present pedal feel. Fronts will present steering wheel feel, rears pedal feel. Sometimes only under certain loads will it be felt. Sometimes only hot, only hard braking, or only light braking. I'm 100% confident in that, but I only work on brakes everyday...

 

this

as in this is proven feedback that I have personally experienced and believe.

 

Don't go with drilled rotors.

Purpose built race cars or production cars with upgraded brakes (bigger rotors, etc) do it because the rotors are big enough (have enough material) to allow the 'heat sink'. When you apply the brakes, the pads & rotors contact with the resulting friction causing heat. The rotor mass needs to 'absorb' and then dissipate that heat. While the argument can be made that you will have more surface area with the holes, it won't be enough to make up for the material loss.

Using the same size rotor, but drilling holes, removes mass. That is why a older and/or resurfaced rotor seems to warp more quickly/easily.

Speaking of the ability to absorb heat, that brings us to brake fade. Basically, if you overcome the rotors (or drums) ability to shed & then absorb heat again, you will experience brake fade. Brake fade associated to pad/shoes 'off gassing' (green fade) is largely a thing of the past. That is because the synthetic friction materials & specifically binding agents (resins) of today typically won't off gas like pads/shoes of the past.

When I used to race (production based cars), we would go through rotors often. This is even with purpose built ducting to the front rotors.

 

Have cross drilled, slotted rotors on mine. So far with no issues. Was aware of the potential cracking on drilling but was assured if it did, it would be warranted.....we'll see.

 

Spot on...
I've raced SCCA (GT1/SPO, AS, IT) and know this as fact...
The cross drilling of rotors is mostly a feel-good throw back to the days before carbon-metallic and ceramic friction compounds. Those old organic / asbestos brake shoes and pads would outgas terribly and that gas would build up a boundary layer between the rotor and the pad. That led companies like Ferrari, Lamborghini, Porsche, et al, to drill their rotors in order to expell that gas to the inside of the vented rotors. We've not needed drilled rotors ever since VelvetTouch introduced the metallic brake pad in the early 70's..

As far as keeping the drilled rotors and staying safe - I would monitor them closely and watch for hairline cracks radiating outward from the holes in all directions. The toughest surface to monitor is the inside of the rotor (toward the center of the vehicle). This is the hottest side of the rotor and is likely to start cracking first.
One other point to consider is thermal shock. If you can avoid going through water when your brakes are hot, I would do so.

One other thing to do to maintain really good brakes is to bleed your brakes every couple of years. The boiling point of the fluid reduces over time and can lead to a soft pedal right when you need it the most. In racing, we would bleed our brakes after every session on the track. I used some of the highest boiling point fluids available like Castrol SRF and Performance Friction fluid..

 

Thanks for the tips Big-Foot...I will be monitoring closely.

 

Lots of great info here.

Randy's brake flush/bleed advice is excellent and something I feel is important as well, and very easy to do (use dot 3 or 4 fluid-the cap says 3 but they are interchangeable/mixable). Also take the opportunity to grease the slide pins at the same time, dragging pads preheating the brakes doesn't do you any favors either.

 

I had to cancel my Ford dealership appointment on Thursday because of a last minute business trip. This is some great feedback, I believe it is warped brake rotors and I do not want them turned, that's what Ford will want to do. I will monitor the problem on our 4th July trip back to the mountains and deside if I need to buy new rotors.

Thanks,

Stan

 

It's possible that your rotors are fine though. My experiences give me that pulsing oscillation when I'm towing the big trailer and braking at high speed on a downhill grade. It happens when the brakes get real hot, it's the heaviest I get and the most severe braking I ever do.

When I'm towing the normal stuff and driving normally it never happens for me. In my case it's just overheated brakes. Vibration and fade. When unloaded or with the normal 8-10k trailer, I can ride the brake pedal as much as I want and I feel nothing, nada.

So, while you may have an issue, and I may have an issue, it might be hard to pin it down.