I have a 98 F150 4.6 with front discs/rear drums. I get a pulsating from the front when I stop, sometimes. Sometimes it doesn't happen at all, others it shakes the truck enough to knock my cell phone out of its holder. I also get a squeak from the rear drivers side brake. I just had the truck inspected and the shop (dealer) said all of the pads were fine. One would assume the front is a warped rotor, but why doesn't it shake all the time? I noticed the other day that when I shut the truck off and pump the pedal, the rear drivers side brake's squeak as the brake is being applied and released. Please advise. I think the back brake is either a cleaning problem or something needs to be lubed.

My question on the front brakes is this. Sometimes, the pedal travel is noticably farther than others. When the travel is a lot (almost to the floor) is when the shudder is the worst. I know that there is a brake booster on this truck. Could it be bad? Am I feeling the antilock brakes going nuts to try to stop the truck?

 

I agree with all your observations. I don't think its the rotor as yes you should feel it always.

Yes I think you need to lube something in the rtear assembly.

Yes I think the problem is either in the master cylinder or power assist. I don't think it is your ABS failing.

Having said all that, I'd probably inspect and measure my rotors anyway and have them turned if they are out.

Now..I might also suggest you check the condition of your brakefluid. Brakefluid gets in-efficent as it ages, it absorbs water ansd you could push it into a condition you describe by hard braking or hot braking. The fluid simply begins to boil from the water and the breakdown. It is a pretty easy process to purge and replace your brakefluid.

I'd do both of those before I damned my master cylinder or power assist.

But this doesn't seem like much help to read now does it?

TallTom