Braking problem on 92 legacy

[ron2368]

I have a 92 legacy fwd. The rear discs were redone within the last year. The last 2 days I hear and feel a loud vibration from the rear when I brake, its like a harmonic boom-boom sound. I remember something similar about 10 yrs ago and the dealer said that something in the brake needed to be greased. I took the wheel off and there was nothing I could see needed work but then I really had little idea of what I was doing. Any help appreciated. Thank you

 

BTW I also have constant valve rattle, its almost funny the car sounds pitiful. I saw the threads on a knock sensor but where is it and how do I know its bad? Is it cheap , I can buy a new one? thanks again

[Legacy777]

The only thing that needs greasing is the caliper guide pins. However if the dealer had the caliper off to check this and didn't grease them, that's pretty shotty service.

 

As for the vibration, did you just have new brake pads put on? It's possible the old pad material on the rotor is causing an intermittant deposit of the new pad material and causing the shimmy you feel. You can try taking the rotors off and sanding them to see if that helps.

 

Where do you feel the vibration? In the steering wheel or in the brake pedal?

 

 

The valve noise is probably from the lifters. If the oil wasn't changed regularly, it's possible crud got into the hydraulic lifters and gummed things up.

[ron2368]

I did not notice the noise at all today. The day it started was rainy and I had done 30 minutes of driving when it started . Maybe something was stuck. I looked under each wheel and all looked ok.

 

Oil will be done by end of week. Thank you.