Squeal or Ringing noise in rear brakes - 74 L Bug.

I've had this problem with bone stock daily driven 74 L Bug for quite a while now.

When I go over about 60kph a high pitched, speed dependant "ring, ring, ring" is audible from the right rear wheel. It's more audible with the window down and even more so if a truck is passing or I'm driving near a concrete barrier on the freeway. Note it is not a rumble or girnding noise like a wheel bearing is going.

If I press the brake pedal even slightly, the squeal goes away for a couple of seconds, then returns. Yet if I pull on the handbrake a little the squeal does NOT go away.

Shifting into neutral and coasting or disengaging the clutch makes no difference to the noise.

Both rear wheels have very slight, barely detectable, play when rocked at the "ten to four" position by hand. They both rotate nicely with no significant noise or tight spots evident. Just the usual slight drag expected from correctly adjusted rear drums.

The drums and handbrake are adjusted correctly and there is no evidence of a rear wheel cylinder leak.

After fiddling around myself and not coming up with a reason for the noise I gave up and took it to a brake shop. They cleaned out the rear drums, chamfered the shoes and skimmed the front disks for good measure. They regretted they could not machine the rear drums. After this treatment the noise disappeared for a week, then it was back. However, in that week I didn't do any highway runs.

I am at a loss what to do next. The car drives perfectly, it's just the noise is starting to drive me crazy and I know there is something wrong. Could it be something odd like a bent brake drum? Could it be as simple as replacing or machining the rear drums?

I'd be grateful for any suggestions.

Thanks,

Had a similar (ringing noise) problem that turned out to be a fallen-off retaining clip on the handbrake lever (inside the drum), but if you had drum removed that should have been found.

Also had a vague "brake noise" -- at only higher and distinct speeds -- that turned out to be a slightly worn (blued & chewed) front wheel bearing that could only be seen as faulty when cleaned of grease...
The behaviour was EXACTLY in accordance with your observations in your 2nd and 3rd & 4th paragraphs. It seemed adjusted correctly etc. when checked the usual way. (No rumbling, grinding etc.) I could not believe it was the bearing!...
So could it be right Front? (That fits with the footbrake observation.)

Thanks Brutus.

I suppose it could be the front right rather than the rear right wheel. It is hard to isolate at speed. I have had the rear drums off several times to search for missing/broken/scraped or scuffed components and the brake shop has obviously had them off too.

When I first noticed the problem several months ago it only occurred at around 80kph. Now it's anything above 60kph but thinking about it, it does seem to be when the car has been driven a couple of km first. So it is possible the bearing takes some time to heat up before it becomes noisy.

I intend to change the strut inserts and springs in a couple of weeks, so I will take a closer look at the front bearings.

Thanks,