2003 f150 4x4 When I brake, Front is vibrating

[Roadkingbro]

2003 f150 4x4 When I brake, Front is pulsing. Sorry if this has been address just need to start a new thread. Just point me in the direction. At 35k replaced front Rotors and Pads with NAPA ULTRA PREMIUM. After a bad winter started getting a bad bounce when applying brake. Assumed time to change the rear, even though I couldnt determine front or back. Replaced Rear Rotors and Pads(no noticeable on old rear rotor, slight pitting) at 49k with NAPA ULTRA PREMIUM. Still have a definate pulsing from front while braking. Steering wheel will even pulse at times. Rotors look ok visual?? Its not consistant but always present. At times worst than others.
Thanks!

 

[bepperb]

Sound like a good set of rotors. But, the symptoms would be either runout or thickness variation on the rotors, or an off chance of deposits/poorly bedded pads.

You might try a dial indicator, or just have both fronts turned. Sorry that's probably not what you wanted to hear.

Any chance there is rust or dirt on the mating surface behind the rotors resulting in a wobble? Dial indicator would also find this.

 

[mechtech2]

Warped rotor,
areas of roughness from rust/wear or where a metallic pad sat for too long,
and uneven pad deposits on the rotor.
Gotta look and test.

 

[Schmoe]

Had the EXACT same problem with my F150. Got a set of front rotors from Autozone and problem went away. After about 10K miles, I can feel it coming back at high speeds, say above 70, but below that, it's like butter. Check your rotors. Take them off and find a brake shop to see if they are within spec's. If not, check the price to have them turned. It may be cheaper to just buy new ones like I did. I think this is a common problem with the F150's. Like the engine oil, you got to replace them every so often.

 

[Scott_Tucker]

The most common reason you will get a vibration in the pedal and steering wheel in thickness variation on the rotor due to deposits from the brake pads. If you drive down a long hill and get the brakes hot and then come to a complete stop and hold your foot on the brakes the pads will bake onto the rotor. This material will cause a slight variation in rotor thickness which can be felt when applying them. Most people refer to this as rotor warpage but if you measure them you'll most likely find thickness variation.

A good article on this can be found at:

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml

Although this article is written about racing brakes, the same principals apply to brakes used on the street.

 

[Schmoe]

That's a GOOD read. An older mechanic taught me that trick when replacing new pads. Hit about 30 -40 or so, slam on the breaks. Do that about 3-4 times and let them cool, then repeat. Should be good to go after that. Pretty close to what I read, just that I wasn't going 60 mph. To this day, any break pads I've replaced, all the vehicles below, I've yet have a problem with brake fade or pulsating pedals. My F150 did that REALLY bad, but I got the truck from my father and Lord only knows what all he did or had replaced.

 

[SteveSRT8]

glad everybody is on board with bedding.

Funny, a while ago everyone here thought that article was [censored].

Where are the naysayers now?

 

[mechtech2]

That article has good and bad in it.
He denies ever seeing warped rotors, for instance.
Everything is bedding and pad deposition.
But he is primarily talking about racing and very hard use.

Normal street use brakes bed in whether you like it or not.