F150 Brakes

[robertc1024]

Ok gents, here's the deal. I've got an '08 F150 and it has started shuddering coming to a stop in the last couple of months. I figured the front rotors were warped so I yanked off the tires and put a dial micrometer on the rotors. One side has about a 0.001" runout, the other has about a 0.005" runout while rotating the rotor. Is that enough to cause the shudder? I measured the thickness and they have enough meat on them to get them turned. Suggestions? Getting them turned is ~$15/per rotor. Replacing them is ~$85/rotor. I checked one of the rear rotors and it was about .005" of runout too.

 

[Brains]

A warped rotor won't shudder, it'll pulse. I'd probably look for a binding or loose caliper or caliper bracket, or perhaps contaminated brake pads (oil or brake fluid leak). Five thou is a little out of spec but not terrible, I think ford full size is a max of four thou.

 

[ROGER4314]

Also check rear axle seal leakage. That lube will make the rears grab.

Flash

 

[Vaquero]

Yep. Get the rotors turned.

 

[Dawico]

Get the rotors turned as long as they aren't cracked. It is cheap enough even if it isn't the issue (but I think it is).

 

[Mic]

That's much newer than our 97, so probably a different ballgame.

I just had to have rotors turned again. Routinely having to get this done.
Our mechanic told me quite a couple years ago to buy a good set made here in the states when I get them replaced - that the cheap ones warp quickly - this was while he had them turned. They did warp within a short period of time, but since this truck is our backup, I was able to wait til recently to have it done. I told him to go ahead and get us a good set this time - we'd pay the price. He came back to tell us - sorry, but now even the Motorcrafts are made in China and that they are all shit now. He turned them and said we'd probably be back in 10,000 miles to do it again. When I asked why my 02 Tahoe has been hammered on for the last 2 years and I've had no problem he told me that the Fords are thin as shit compared to the Tahoe - Chevy put some metal in there. Makes sense - My driving puts stress on brakes, but they've held up strong.

Done ranting - sorry to blab on. Hope they put a little more stout rotors on the newer ones so you aren't in the same boat.

 

[M. Sage]

They're warped. Rule of thumb is if the steering wheel shakes with the brake shudder, it's the fronts. If the truck shakes under braking but the wheel doesn't, it's the rear.

I'm not a huge fan of turning rotors. It can be a bandaid, because thinner rotors warp more easily.

Fun fact: Most common way to warp your rotors is to over-tighten your lug nuts. I 'bout had to slap people at this job to get them to stop just using impact wrenches to install wheels. There are torque-limiters for impact wrenches (special extensions), or just snug them and use a torque wrench.

I'm not sure what years used them, but around the mid '00s, Ford 2wd F150s had the wheel bearings built into the rotors. Pain in the ass to turn, if they can be turned at all. They're also not too cheap, and Ford's torque spec is freakin' wrong and will cause premature bearing failure. If it's got the integrated sealed bearings, I've had good luck tightening them to about 150 ft/lb. Ford tells you something like 250, but everybody I know that's done that has had bearings fail quickly.

 

[rsayloriii]

Fun fact: Most common way to warp your rotors is to over-tighten your lug nuts. I 'bout had to slap people at this job to get them to stop just using impact wrenches to install wheels. There are torque-limiters for impact wrenches (special extensions), or just snug them and use a torque wrench.

Agreed on that's the easiest and probably most common cause. I won't let anyone use impacts on my truck. I've already had to replace the rotors too many times on different vehicles because of it. I don't buy the torque limiters either when the guy sits there hammering away on it. Should run the lugs down to snug in a star pattern and then torque them in a star pattern. And when you're torquing, it's a smooth fluid motion, not a jerk, and once you hear the click, you stop, not go another half turn.

And people wonder why I watch them like a hawk when I've got to get tires worked on ... Because I don't have the thousands of dollars for a good balancer!



Sent from my RobCo Pip-Boy 3000.

 

[robertc1024]

They're warped. Rule of thumb is if the steering wheel shakes with the brake shudder, it's the fronts. If the truck shakes under braking but the wheel doesn't, it's the rear.

I'm not a huge fan of turning rotors. It can be a bandaid, because thinner rotors warp more easily.

Fun fact: Most common way to warp your rotors is to over-tighten your lug nuts. I 'bout had to slap people at this job to get them to stop just using impact wrenches to install wheels. There are torque-limiters for impact wrenches (special extensions), or just snug them and use a torque wrench.

I'm not sure what years used them, but around the mid '00s, Ford 2wd F150s had the wheel bearings built into the rotors. Pain in the ass to turn, if they can be turned at all. They're also not too cheap, and Ford's torque spec is freakin' wrong and will cause premature bearing failure. If it's got the integrated sealed bearings, I've had good luck tightening them to about 150 ft/lb. Ford tells you something like 250, but everybody I know that's done that has had bearings fail quickly.

Yep - kinda of what I thought. I was pretty much surprised at the runout though. It didn't seem like very much. I think I'll just pull all the front rotors off, get new seals and see what happens. I've got the torque specs on the front bearings - you have to cinch it up to a few inch-pounds and back it off a bit. I'll probably do it by feel though. Car/truck undriven bearings need to be just barely tight with no slop at all. I'll get the front's cut - if they go bad again, I'll just get new rotors. I've heard many times over the years that once they get warped, getting them cut is just a band-aid. My thinking is that if it works for a while, I've got that much money for a new gun. By the way, RockAuto is pretty much awesome for getting car parts. They are at least 25% cheaper than local parts stores.

 

[RetArmySgt]

I just had the entire brake system upgraded on my 2007 F150, was eating pads every month and a half for some reason. That did not get rid of the front end shake that i have been getting as i come to a stop. I have noticed that it shakes as it passes below 750rpm and as it rises above 750rpm as i leave the light. Im thinking it might actually be in the engine or a mount and not the brakes.

 

[M. Sage]

I just had the entire brake system upgraded on my 2007 F150, was eating pads every month and a half for some reason. That did not get rid of the front end shake that i have been getting as i come to a stop. I have noticed that it shakes as it passes below 750rpm and as it rises above 750rpm as i leave the light. Im thinking it might actually be in the engine or a mount and not the brakes.

Something engine-related. Check your crank pulley for wobble.

 

[M. Sage]

I use torque extensions exclusively. You can't over-tighten with them unless you have a ridiculously stout impact. Have yet to mess up rotors since I started using them around 14 years ago.

It's just a torsion bar.

Yep - kinda of what I thought. I was pretty much surprised at the runout though. It didn't seem like very much. I think I'll just pull all the front rotors off, get new seals and see what happens. I've got the torque specs on the front bearings - you have to cinch it up to a few inch-pounds and back it off a bit. I'll probably do it by feel though. Car/truck undriven bearings need to be just barely tight with no slop at all. I'll get the front's cut - if they go bad again, I'll just get new rotors. I've heard many times over the years that once they get warped, getting them cut is just a band-aid. My thinking is that if it works for a while, I've got that much money for a new gun. By the way, RockAuto is pretty much awesome for getting car parts. They are at least 25% cheaper than local parts stores.

The runout is the first symptom. Over time, you run into parallelism issues through wear. You can usually spot warped rotors by the wear pattern.

Oh, one other way to mess a rotor up and cause pulsation is dropping it on its edge. Puts a dent in the rotor, causes parallelism to go out of spec.

 

[robertc1216]

I'm not sure what years used them, but around the mid '00s, Ford 2wd F150s had the wheel bearings built into the rotors. Pain in the ass to turn, if they can be turned at all. They're also not too cheap, and Ford's torque spec is freakin' wrong and will cause premature bearing failure. If it's got the integrated sealed bearings, I've had good luck tightening them to about 150 ft/lb. Ford tells you something like 250, but everybody I know that's done that has had bearings fail quickly.

My 08 had rotors like that. I bought the hubs that allowed you to use the 4x4 rotors. With buying the new rotors and hubs I was right around what the 4x2 rotor would have cost. So next rotor swap I would have been out ahead.

 

[RetArmySgt]

Something engine-related. Check your crank pulley for wobble.

Just went out and tried to wobble the pulleys and couldnt find one that would move.

 

[M. Sage]

My 08 had rotors like that. I bought the hubs that allowed you to use the 4x4 rotors. With buying the new rotors and hubs I was right around what the 4x2 rotor would have cost. So next rotor swap I would have been out ahead.

Nice! Had no idea that existed, I'll have to check it out!

Just went out and tried to wobble the pulleys and couldnt find one that would move.

No, fire up the engine and look at the crank pulley to make sure it doesn't look like it's wobbling as the engine runs. There's a layer of rubber between the hub of the pulley and the part the belt rides on. That rubber goes bad over time, and one problem it can cause is the outer part of the pulley getting out of alignment, causing imbalance and vibration. If that's the case, you want to change it ASAP, because it's going to wear crank bearings faster.