About a month ago, I started to experience a vibration when lightly applying the brake pedal. It is not a pulsing pedal like you would have if the brake rotors were warped. I elevated the car and supported it with jackstands. Upon inspection, I noticed that the rubber booths for the ball joints had perished. I replaced the upper and lower ball joints on both sides, the brake rotors, brake pads, front shocks, sway bar rubbers and steering ends.
I checked the upper and lower control arm bushings and they were in good condition. The wheel bearings are in good condition and adjusted properly
Now the vibration is more pronounced. Probably due to the pair of Woodhead shocks I purchased from Welsh. The car does ride a little rougher with these shocks. I may put back the old BOGE shocks to see if the nice ride returns. All of this happened after I removed the engine to attend to some leaking freeze plugs leaving the transmission in place and I don't know if that had anything to do with it. Prior to this I never had any vibration issues when I applied the brakes.
My plan is to lift the car again and look at the motor mounts and transmission support. I will also inspect the front subframe bushings while I am there.
In the meantime if anybody has any ideas or experienced the above condition please let me know what you did to resolve this issue.
BTW: This is my LUMPED XJ6.

 

I experienced brake shudder after fitting new discs & pads. So I went to the (unnecessary) expense of buying yet another set (grooved rotors this time).
Turns out when disassembling, I discovered I failed to correctly torque up the discs to the hubs first time around, hence the problem.
Hopefully, you have not been so negligent!

 

Agreed. That is something I thought about. I will recheck the torque specs of the rotors. Thanks.