That was 6 years ago, I have no idea what I did. I had a lot going on in my life back in those days, parent in ICU, college, working and taking care of my family.

 

Well, now that this thread is dug up, I'll chime in and say I've been having this issue for a little while, but I just ignored it. My shock absorbers are in good shape, but my brake pads are all approaching minimum thickness, and my rear rotors look pretty rough.

I'm going to throw all-new pads and rotors on in addition to stainless steel brake hoses.

All this being said, I kinda suspect something is going on in my rear differential causing the vibration/shudder, and not the brakes. Mine occurs from 44-40 mph, tho. Coasting or maintaining speed is a light vibration/shudder, and braking just makes it worse.

 

Most likely the rear brake rotors are warped. It's a common problem with these trucks.

 

I can confirm that a few years after I created this thread, I did get my rotors turned and it did not fix it. I also had my rear end rebuilt because the ring and pinion were ate up along with the clutch packs needed replaced, that also did not fix it completely, but it eliminated a good bit of it. I then had replaced all 4 tires and low and behold the problem was no longer there. I guess I had a few different problems occurring that created one big problem and all contributed to it equally.

 

That is why I buy expensive Michelins and have them balanced regularly. They run smooth and quiet until they are worn out.

 

Can you tell me more about getting your rear diff rebuilt... like how much it cost, etc?

I'm pretty sure my LS is toast with 214k miles on it...

Yea, replacing those are definitely on the list.

 

It all depends on your differential shop, I had everything replaced minus the axles. I convinced myself to take it to a shop instead of doing it myself because I can not warranty my work and the labor the differential shop was my way of convincing myself to take it somewhere. I had 300k miles on mine and never changed the fluid.

 

I only buy Michelins also and I am glad Ford put them on my 2015.
All I can say is STAY AWAY FROM TIRES MADE IN ASIAN COUNTRIES......especially China!
The last thing in the world I would want are tires made by 12 year olds in Asian sweat shops.

 

Have you tried the brake master cylinder?

 

This issue was fixed several years ago.

 

I know old thread, etc. But just add to possible reasons for bounce ... A cousin's F-150 had parking brakes not fully releasing due to rust or something, and he would get down the road a mile or so at speed, then as he was slowing for a stop sign, the rear would bounce at about 40 down to 25 or so he said. I suggested then to try to park on level and not use the brake after grabbing the cables and wiggling them a lot, he said next trip to work was OK. I suggested looking at the parking brakes them selves inside the rear drums made inside the rear rotors. They were egged from heat, his mechanic said, the shoes wore out too, but they found a root cause in rusty or sticking cables. I think he said they replaced the shoes, rotor drums, springs, cables all.