Vibration judder when braking (steer axle) 07 W900

Hi Folks,
I’ve been battling this vibrating (judder) since day 1 when I bought truck.
Problem: Front end vibrates judder when braking more noticeable at speeds 70-65 (steadily braking. Seems to decrease or goes away completely at all other speeds under 65-60 .. At 75 and braking it won’t do it unless (not always consistent) if I gradually go into braking (not as hard on pedal) ..

Attempts to solve: I figure this was a no brainer and replaced s-cam bushings, shoes and drums. My luck didn’t solve anything. Going back to re-checking hardware, I realized that passenger steer brake was dragging at a certain spot and free on rest of rotation. I thought to myself surely this is my problem. I began replacing in order to no success (spider bracket, s-cam, complete wheelhub assembly, (king pins were new) and once more another set drums shoes after the fact) brake still dragging.. I was about to replace spindle but didn’t want to believe that would be cause but at that point I didn’t know what else could be wrong.. one day I saw that I overlooked the (s-cam Bracket) and figure it’s cheaper than spindle so I tried it. Finally that solved my brake dragging issue and at this point I thought I had solved my vibration issues as well. You guessed it I had not solved it.

So I have all those new parts, new shocks, oh and I also replaced (ALL) spring axle bushings .

What I can confirm is that vibration is definitely in the front because I isolated issue by disabling front brakes; One at a time and eventually both at same time because it would do it with either side working.

Seems when Truck is empty it does not do it as much or “intense” per say. But overall feel is exactly as if my drums were “out of round” warped etc. I’m at a hard hit against the wall.. don’t know what else could be my problem anything you guys can think I have missed???

I even thought maybe my abs modulator on front are faulty so I disconnected both to see if it would eliminate my problem but there was no change. I figure if it’s disconnected the front braking would operate as normal braking.

Please folks I’m in need of advice! Thanks

 

Anybody has any input?

 

Yes very strange indeed. I need to do something like that see if my numbers become erratic when vibration occurs..