Bet you a dollar to a doughnut it's your rotors...

 

Also, do NOT tighten your lug nuts with an impact gun, even with those supposed "torque sticks" or whatever crap they call them now. On most setups that'll warp the hub and along with it, the rotor. That'sone of the biggestcauses of warped rotors on most cars, the wheel jerks zip up the lug nuts instead of torquing them

 

Something else poped in my mind. A loose wheel bearing can cause a vibration at that speed (said by andrew).Earlier when I said bad tire, maybe a broken belt or seperationthat can not be seen but amplified during braking.Let us know what the fix is.

 

i torque them down to 110 lbs with a proto torque wrench. i did a run out with a dial gauge and have under 5 thousands. i did see some imperfections in the spindle castings, could be cracks. ill have to rotate the tires and check it out again. first the mech. said it was my steering stabilizer rubbers, they are squeezed out. then he said it was my pitman arm. i told thats nuts, the pitman arm would have to be cracked, the excess play was in the control valve pivot ball. well thats all new now, not really that bad of a job, but not the problem, i say tires or somehow the master cylinder is pulsing. the power brake booster and master are pretty new. everything ive done has helped but the thing that made the biggest difference is when i aired up the tires from 23-44 psi, that what the max pressure said on the side of them. that cut the vibration in half.

 

Could be the tire itself too. When you brake it increases weight on the front tires, maybe it's got a belt that's failing and the tire flexes when you brake. What's the max runout for your rotors supposed to be?

 

Checking the run out on a COLD rotor will not always show you worpage. Some times the rotors will look fine cold, but as soon as they get warm the runout will increase. My money is still on the rotors especially sense you replaced the pads with out turning the rotors. Pads and rotors ware together and an untrue surface and new pads will make for problems.

 

wheel bearing can do that it would take a while before your tires wear funny. easiest way i found to see if its the rotor or wheel bearing is pull your pads out of one of them is alot thinner its either rotor or wheel bearing.rotors are tricky i had a brand new one act like it was worped i turned it replaced the pads did the same thing i found out it was out of blance it way it did that.yes torqueing the lug nuts is a must i walked out from a ford dealer here over that.shop manager said i was wasting there time torquing them. i told him do not speak to me again tell you read a shop manual go sit in your office and act like you know something.

 

I SAY ROTORS, IF THEY HAVE BEEN TURNED THEY WARP AT THE FIRST PANIC STOP.

 

but i checked the rotors and there under 5 thousands out. and i replaced the brake shoes and calipers over a year ago. i need to swap the rear tires to the front first, if it still does it then ill buy a set of rotors.