Pulsing in brake pedal, 1998 ford expedition

Hey guys. You have always come through for me so I am back again. I have a 98 Ford expedition that I rotated the tires on about 2 weeks ago. Since then, there has been a pulsing sensation when you press the brakes. It is my wife’s car and she says it has been there a while, but has gotten worse since the rotation. It definitely corresponds with the speed of the vehicle; it gets slower as the vehicle does. I checked the fluid level. My first guess is a warped rotor. I just want to be sure it is not something more serious since we were planning a trip in this vehicle for the holidays, and don’t want to wind up with no brakes half way through. Any thoughts? Thanks again to the car talk community.

Yes, it does sound like a warped rotor.
Since the problem began right after you rotated the tires, I have to ask:

Did you use a torque wrench to tighten the lug nuts to Ford’s specifications?

If the answer to the above question is no, then I urge you to buy a torque wrench, because over-tightened/unevenly-tightened lug nuts are a prime cause of warped brake rotors.

Harbor Freight sells torque wrenches for ~$20 or so, and for occasional use these cheap tools are sufficient.
And, investing $20-25 in a torque wrench is FAR cheaper than buying new brake rotors.

Your present rotors may be too far gone for any help at this point, but at least if you can avoid ruining the next set of rotors, you will save yourself a whole heap of money. Your Owner’s Manual should list the correct torque for the lug nuts, but if it doesn’t, a call to your Ford dealer or to a reputable tire store should yield the correct info for you.

I would assume the rotors as well. Replace them along with the pads and you should be ready to go. Happy Holidays.

No warning lights? (check engine, abs, brake, etc.)

Warped rotor. Replace them, don’t turn them. When you put the wheels back on, use a torque wrench to get the torque even on all lugs and make sure you tighten them in a zigzag pattern.

Thanks for all the advice. I did not use a lug wrench so I am pretty sure that is it as well. How dangerous is it for us to take a 80 mile trip on Saturday.

This is satstro again. Is there a way to tell which one is warped? I am definitely going to pick up a torque wrench to avoid this happening again. Also how dangerous would an 80 mile trip be in this current condition.

There is no danger for your trip, it will just be annoying.
There are ways to tell which one, but your would be better off (and safer) to replace both front rotors and pads. The rotors should not be expensive.

You might loosen the lug nuts and then re-tighten them in 3 stages in a criss-cross pattern and find that the problem disappears. If one lug is turned down to 90+/- lb ft and then the remaining lugs tightened in any pattern the rotor will be “warped” in its position but likely not physically warped.

An 80 mile trip isn’t that much distance. It seems you don’t have anytime to do anything to the SUV before you go. If you have time have the tires rotated at a tire shop. When they tighten the wheels on perhaps your pulsing will be a bit better.

If you have no time, you should be ok for your trip. This isn’t a hydralic problem so your brakes will stop you, not smoothly but you will stop.

The pulsing pedal symptom most often gets attributed to warped rotors. Not that it makes any difference in the repair (replace rotors) but in my experience, the pulsing pedal is caused by rust and nothing more. Notice the “image” of a brake pad on the rotor every time a car has been parked for even just a few hours. The braking friction surface is eneven in friction coefficient resulting in the same pulsing you’d get from a warped rotor. Yes, I too torque lus nuts/bolts but I don’t think those peices of cast iron are a sensitive to warping that most think they are. I’ve never replaced my own pads and rotors due to wear…its always been rust. It seems as though living in NH, 3 years is about the replacement cycle no matter how much mileage.

Now I’m really curious.
If you didn’t use a lug wrench, and you didn’t use a torque wrench, what did you use to tighten the lug nuts?

So sorry. In a bit of a frenzy and mis-typed. Did use a lug wrench, not a torque wrench.

ABS gone bad?

 You should have used a torque wrench.  You can warp the rotors with a lug wrench.  That sounds like what has happened.  It is not 100% sure, it could have warped for other reasons, but ??

Your trip will probably be fine but new rotors is in your future. My brake guys will retourqe for free just to avoid rotor problems. Any old lugnut with a torque wrence has not a clue of how may rotors have been ruined by improper tightening.