Subject: Squeal or Ringing noise in rear brakes - 74 L Bug.
bnicho
A.k.a.: Brett Nicholson
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posted on June 10th, 2014 at 01:43 PM
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,
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
BRUTUS
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posted on June 10th, 2014 at 07:24 PM
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.)
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bnicho
A.k.a.: Brett Nicholson
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posted on June 11th, 2014 at 09:25 AM
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,
Brett Nicholson
Melbourne, Victoria
1974 VW Superbug L - Olive
1971 Morris Mini Moke - Mopoke
1966 Austin Mini - Audrey
1965 Morris Mini Traveller - Trixie
2007 Land Rover Freelander 2
2009 Nissan Pathfinder
posted on June 10th, 2014 at 01:43 PM
