I have been battling a rear braking problem for quite a while on my 1990 240DL wagon with 196K miles. Every year I threaten to retire it but I don’t have the heart. I love driving it.

When I brake, I get a bad vibration in the rear that seems to be the frequency of the wheel rotation. It seems to be mostly on the driver’s side.

It feels like a badly warped rotor.

However, I am suspecting a bad wheel bearing as I can feel a slight bit of top to bottom play in the rear driver’s wheel when I have the car jacked up.

I recently replaced the calipers which had never been done. Although needed, the problem did not go away, nor did I expect it to.

I have also replaced the rotors. Here is what has me puzzled. After the rotors were replaced, the braking was noticeably smoother. For a few hundred miles I thought the problem was solved, but the bad vibration always seems to come back. Recently, I replaced the driver’s side rotor again and the vibration went away again for a few hundred miles. Now it is back.

I know from experience with my front brakes that a loose wheel bearing can cause the bad vibration as once I had this same issue on my front driver’s side. I simply tightened the castle nut and the vibration went away. Unfortunately, there is no castle nut on my rear spindle and I have not yet changed a rear wheel bearing.

Can any of you explain my observations and/or give me some advice?

Thanks very much

TwoOldVolvos (except I’m down to one since I junked my 89 240 sedan.)