2006 Lincoln Mark LT- I am getting some vibration in the front when braking, Most front end components are newer: shocks, ball joints, tie rod ends (replaced in Nov 2020). Brakes were not that old but I used a pads and rotor package off amazon that was made by Detroit Axle. Decided to replace in Dec. Wagner brakes, Rotors from local parts store (unknown brand), New passenger caliper (driver side was replaced with shocks, etc) and New brake hoses as well. Started getting the vibration again. Intermediate steering shaft kept freezing up, so I had a shop replace due to how hard it was to get to lower bolts. Mechanic told me I had a bad rotor. I took them back to local parts store. They turned them but said they were not bad at all. Pads were still in great shape and worn evenly. Put everything back together and still getting vibration. I'm stuck. Going to get the tires rotated and balanced to see if that helps. Any insights?

 

We don't serve your kind here!

Just kidding. Where are you feeling the vibration? Brake pedal? Steering wheel?

 

Definitely the pedal. I thought maybe an ABS issue but the hubs were replaced in Jan 2020 and there is no indicator or codes.

 

Rotors of unknown brand would be my suspicion.

 

If the rotors are 100% good (depends on how much you trust the local parts store) I would check some other things like the condition of the slide pins for instances. I've had a slide pin that was slightly warped cause a lot of vibration issues but this would typically happen at any speed.

Speaking of which at what speed is this noticeable? Around the 50mph+ range or does this also occur during slower speed stops?

Does it stop vibrating as soon as you let off the brake pedal?

Another thing to check is your soft lines going to your calipers. These lines have ribs on the outside which are pretty easy to see. Follow these ridges and be sure the line is not twisted.

Does the truck pull one way or the other when braking?

Brake dust building up on one side more than the other?

If replacing the rotors fixed it the first time and it's back again then i'm with Taco on the rotors. Which begs the question, were they cheap rotors? Or is the other caliper hanging up and heating up/warping the rotors.

 

Solid point on the slide pins, those things are neglected by most. Should be pulled, cleaned, lubed each time the pads are replaced, or every other year, whichever comes first. The rubber boot should be replaced every other time you clean and lube them. The past four vehicles I owned got this maintenance, the pins lasted to the vehicle end of life on each, one of them living until 245k.

Put a smidge of grease on the lip where the boots seats and just past it to prevent rust creep under the outer lip of the boot. Once you get a bit of rust up under the edge of the boot, water will get inside and damage the pin and bracket, earning you a sticky slide.

 

It will do it at lower speeds but with less intensity and it does stop after taking my foot off. It doesn't pull and not any brake dust build up either. Calipers are good, slides seemed good, pad slots are greased good. Like I said on the rotors, there was no brand name. They were $45 a piece and when the shop turned them, he said they were still in good shape and barely took anything off. I checked all that when putting back together. .I'll look at the rears this weekend. I didn't consider that they may be the issue and was just flowing up to make it seem like the front.

 

There should be zero vibration induced by rotors when they have been turned, so I think your front end brake system is good. This is presuming the shop checked runout after turning the rotors.

Vibration coming from the rear rotors is rare, as it's not common to get them hot enough to fuse pad material, and their bias is lower, so they don't give as much pedal feedback. But it is possible.

 

As FlamingTaco mentioned it's far less likely that it's from the rears although not impossible. And a warped rotor traditionally doesn't cause slow speed vibrations unless it's gotten really bad but you said they were turned and were in good condition. I would still check the lines to be sure they aren't twisted and maybe even do a full bleed to ensure there isn't any air in the lines as well. Also check the slide pins again to be sure they aren't warped or anything. My slide pin was slightly warped in my Audi and it caused vibrations at any speed although it was more of a pulsation at lower speeds.