I recently replaced the front rotors, pads and calipers on my '92 F-150, 4x4. I also replaced all wheel bearing and races. Upon dissambly, I realized that there were some minor differences betwen the driver and pass. side spindle nut. The driver side had lesser torque than the passenger side. More about that in a bit.

The rotors roughly have 3k on them. I've noticed that between 38 and 25 mph, I get a vibration from the front end. I know everything alignment wise is correct, it was just aligned 2 weeks ago and they said and so did the computer, everything was in spec with oct. last year. Good for the reassurance. The vibration has caught my attention since these were Wagner rotors and pads, 50 for each rotor and 50 for a set of pads. I torqued all the lug nuts to 90 lbs, 2 different torque wrenches, so I knew that wasn't my problem.

My truck also has the auto-locking hubs. No biggies but the differences here are unique. On the passenger side spindle, I have torque the spindle nut to about 27 lbs to get tire to spin freely when it is tuned left or right, or either it wants lock up the 4wd mechanism. Even when it torqued to this setting, it wants to spin a bit more free than the driver side. On the driver side if I torque the spindle nut more than 15 lbs as stated in the manual, it only spins about* half a turn freely with the pads and caliper assembled with the tire on, and the tire torqued to 90 lbs.
Using the clock as a reference, the driver side @ 15 lbs.-5 to 6 o'clock
The passenger side @ 27 lbs.-7 to 9 o'clock

Not the best measurement in the world but differences. When I first changed the calipers(remans of course), I had to swap them out a week later because, I could not get the bleeder screws to quite seeping fluid. They were loose in the threads. So I got those replaced. I have bled all the air I can believe to be in the lines, and new hoses on both sides.

I have also noticed that on my rotors, looking at them from front, the half-inch from the top and a half-inch from the bottom appear to be making the only contact, with minimal contact on the 1 and a quarter-inch center, where-as on the back-side(driver side rotor), it looks like the entire pad is making contact. i cannot really tell about the pass. side since it still has the brake shield intact, but looking thru the holes it looks the same as the driver side.
I also replaced all slide pins and used caliper compound on them.

So does anyone know where I screwed up? I believe I need to replace the reman. calipers with brand new ones. I will have to come up with something soon or take it to a qualified mechanic, with winter coming on fast.

Anyone with any ideas, or where to start, I look forward to hearing them.
Thanks again for looking!

 

Brake pulsations means warped rotors.. it's as simple as that. It's a sign of the times when rotors are warped right out of the box, hard to believe that is even possible but I replaced my rotors 3 times in 2 years trying to eliminate this and finally took a brand new set of rotors to a shop to have them turned before I installed them on the truck, that fixed the problem.
As for the differences in TQ specs on your truck well.. it is what it is. These trucks are not models of engineering accuracy and as already stated many replacement parts are now even worse, don't sweat the details as long as it works.

 

thanks so much for replying Conanski. I had warped rotors on my dodge and it would shake your filling out between 48 and 35 mph. But with the pulsation or vibration very little @ 38 to 28 mph, I wouldn't believe it.
With the indication of the contact area as stated, .."I have also noticed that on my rotors, looking at them from front, the half-inch from the top and a half-inch from the bottom appear to be making the only contact, with minimal contact on the 1 and a quarter-inch center, where-as on the back-side(driver side rotor), it looks like the entire pad is making contact.", does that fit the profile?

I also tapped the spindle lug nuts back in, with a criss-crossing pattern. Once I got them as far as they would go, I used my C-clamp with a bigsocket to ensure they were as far as they could go. I don't have a press to use, so does that make a difference?

Thanks for the reply!

 

Darn, forgot to add about the pads.

Once I turn the rotors, should I scuff the pads really well with coarse grit paper? I haven't hit the pads hard except when someone pulls out in front of me...

 

andym and myself recommend this with new rotors.

 

will definately pursue this asap. Have to work tonight and tomorrow, but all weekend off. Hope the weather here holds up, chance of rain next 3 days. My g/f said that I'm hypochondriac about the truck, but have been telling her the last several weeks it was doing it..lol.

Will get back to you guys when I get it back together! Thanks for all the help and still up for anyone's experiences!

 

You beat me to it.

Always turn new rotors before you install them. All it takes is one UPS driver to drop the box and they're warped.

 

if you get new rotors or have them turned, I would get new pads too. that way it will be done right!

 

Not necessary, you can just scuff up the pads lightly with sandpaper.

 

The new pads that are on there, only have 3k on them or less, @ 50$ plus tax, so I'm gonna try and scuff them lightly with sandpaper as AndyM stated, but will watch them closely after reinstalling them.

 

Update:

I pulled the calipers off of the rotors. I preceded then to check the action of the calipers only to find that the passenger side caliper starts to extend out whenever I press down the brake pedal. There is zero to no extention of the driver side caliper. Does that indicate a bad caliper? I have down it several times and have gotten the passenger side caliper to extend out a little more than a quarter-inch, with about 4 presses of the brake pedal.

Should continue with pulling the rotors and have them checked at the shop for warpage?

Thanks again Everyone!

 

Update:

I tried some advice and simply put a block of wood and c-clamp against the piston. once I made a few turns back, I got back in and tried the brake pedal, finally the driver side piston started to emerge. Well, after constantly going back and forth I noticed that on the passenger side, the point-of-contact around pistons was rusty, wet oily. I then checked the driver side. Needlessly to say it's dry as a bone around the edge of the boot that is extended out with the piston mating surface.

So I'm sure I have answered my 1st update, except the turning rotors statement, but would be a good idea though I'm sure. I believe the passenger side caliper is seeping around the boot and not allowing for a complete pressure buildup since it's easier to turn the wheel with the front-end jacked up, when it takes more force to turn the driver side when all the hardware is connected. Looking at it, I can tell the driver side pads are doing more work than the passenger side, which is why I feel a moderate pull to the left when braking at certain times.

Still looking forward to all suggestions!

 

sounds like time to replace both calipers and have the rotors turned at the same time.

 

Update:

I took the rotors to a Machine shop and got them back. Got everything back together. The passenger side rotor had to be cut a little, but the driver side was in good shape. I got the passenger caliper replaced. It hasn't leaked anything but haven't driven it yet.

I do have a quick question concerning the hub. I have already replaced the bearings when I replaced the rotors and everything the first time. I torqued the spindle nut to seat the bearing, and then backed it off 90 degrees, and then retorqued them to either 15 or 20 lbs. Do I always need to torque the spindle nut in the hub to seat the bearing, then back it off 90, then retorque it to 15 or 20 lbs.?
I could understand if I replaced the bearing's again, but I want to be sure. I didn't torque the spindle nut to 70 lbs., then back it off 90, and then retorque to 15 or 20. I just regreased the inner and outer bearing and slid them back on the spindle and torqued them to 15 or 20 lbs.

 

the rule is: REPLACE CALIPERS IN PAIRS.

why do all this work and cheap out here?