I just brought the 2004 XC70 to replace the '03 V70 totaled from a rear end...

I have done all the fluids change (oil, brake, power steering, tranny, AOC, rear diff., bevel gear, coolant)

changed brake pads and front rotors, and only thing left is timing belt (it has 97k)

The car had pulse vibration when I brought it, I changed the pads, and front rotor, thinking it was "wrapped brake", I first changed pads, then rotors a week later. I noticed the new pads in front, have only the outer part (2/3) wearing mark, the inner 1/3 seem not even contact the rotor after a week!

Still, after I replaced the rotors this afternoon, the pulse vibration is still there, it gets better, but I can still feel it when braking.

what could be the cause for the vibration? it was very typical "wrapped brake" symptoms: light braking feel the pulsing vibration from brake pedal, as well as the noise, harder brake feel less vibration.

Any advice is appreciated...

TIA

 

Rear rotors warped?

 

The noise seems is from front, though not 100% sure, I am going to do rear rotor tomorrow, or next weekend...

 

Does the brake pedal feel like it is pulsing?
If so then it might be the rears. If the steering wheel is shaking then it is the front.

 

only the brake pedal feel the vibration, steering wheel does not.

I will see if doing rear rotor will fix it or not.

thanks

 

Keep us updated.

 

OK, finally, I got change to change the rear disc today...

I think it answers most of the questions. Both rear disc has a section on the inner side of disc that show "rough" surface, see attached pictures. one is wider and worse than the other disc.

dont understand/know how it could cause that, I am pretty sure the previous owner is not a racer (rather a farmer), but the surface overall seems "even", i.e. I was expecting some area are "higher" than the other, I guess those are not distinguishable by human eyes, the "rough" spot, is enough to cause the pulse vibration and noise.

the car is braking smooth now, as it should be!

Now, it still does not answer the question , why the new pads (front) on old disc, show only 2/3 of surface used...

I think Howard's post, on out of spec caliper( http://www.freewebs.com/howardsvolvos/brakes.htm) might be the answer, though I need to check it . I do recall that the front pad is a bit "difficult" to seat in caliper when I did the pad work (and later the disc work), I will try to do a measurement to see if that is the issue, or how the front pads are doing, may be in couple of weeks, since I need to figure out when to do my timing belt...

again, thanks Tech