Mystery Sound

[J. Huber]

Hi. I am hearing a sound. Wondering of anyone identify it? Here is the scenerio: while driving at speeds of maybe 35-40 MPH as I veer into a sweeping lefthand curve I hear a high-pitched cricket sound. It stops as I straighten out. Doesn't seem to happen on righthand turns. Happens without any braking, although I have heard the pitch while gently braking as well. If my ears are working, I think its coming front or rear wheel area? Any thoughts?

James
63 230SL

[merrill]

I have the same thing, I bet it is a bearing going or is bad

[waltklatt]

Need to borrow my hearing aid?  
There are a lot of things that can make it squeal like that.
Is this a new sound not heard before?  What have you changed on your car before the squealing?  
If its the front then it could be the brake line rubbing, tire rubbing, bearing, power steering pump, motor mounts, brake dust sheild, caliper, shocks, etc.
From the rear, bearing, axle shifting, transmission mount, axle mount, etc.
But first it's best to sort of pinpoint the noise location and then you can narrow the culprits.
I'm hearing the squealing all the time-tinnitus in my ears.
Walter

I think its coming front or rear wheel area? Any thoughts?

James
63 230SL

[J. Huber]

Good questions Walt. I may have actually been hearing a version of this chirping for a while (ie couple years!). However, when I would hear it previously, it was intermittent, and often just as I gently touched the brakes around a downhill curve. I know the details of this because I hear it in the same part of my (almost) daily drive into town. Always thought it could be the brakes -- but anytime the brakes actually grab there was no sound.

If I am remembering right, this chirp predates new rear brake shoes, drums turned, flex brake hoses, front shoes, and a ton of suspension work. Most recent was e-brake cables. Car brakes and handles beautifully.

Fast-Forward to Yesterday: I took a fairly lengthy curvy drive -- and thats when I noticed it was happening on virtually every twist to the left -- only above 35 MPH.

Looking at your possibilities, we can rule out P/S (ain't got it). I'd say Merrill and your idea of a bearing could be the culprit.

Are there any other tell-tale signs of bearings going bad? What's the job all about? Thanks. And any other ideas very welcome!

James
63 230SL

[Sphe]

This probably isn't it, but I just wanna look at for people. I had a clunking/chirping turning one direction, and then my wheel fell off. Just check your nuts on your tires. Do it for me man. Having a wheel fall off sucks.

Eugene
1965 230SL, Max Speed: Zero

[J. Huber]

Holy Moly. I'm checkin' I'm checkin!... Thanks Sphe!

James
63 230SL

[waltklatt]

James, the bearing failure is hard to detect.  Unload the rear wheels and lift them high up so the tires move freely.  Please put some big blocks to immobilize the car and on a level ground too.  No need to hear of a loss of a good Pagodaer in the obituary.  
Then with the parking brake in off position you can feel a miniscule rocking motion when you lift the wheel up and down and from side to side.  When you feel it, then you have a loose bearing.  
I would also check the differential oil level as it goes low the gears can whine and the lack of oil will allow the bearings to go dry causing the squealing noise.
Walter

[J. Huber]

Well, the lug nuts are tight. That's a relief. I will check the rear wheel play tomorrow. Thanks Guys.

PS On a parts diagram I see a "rear wheel kit" available. Would this be what I am looking for?

James
63 230SL

[Naj ✝︎]

James,
Here's what you're in for if its the bearing:

http://www.sternschuppen.de/technik/en/ha/index.html


I originally missed the english text below each picture!!
naj

65 230SL
68 280SL

[J. Huber]

Yikes. To me that looks like brain surgery, rocket science, etc... how does it rate for you mechanics out there? Any idea what the labor hours might be?

Now for the preliminary test results. I jacked up rear end and have it on jack stands (under axle -- is this ok). I did a to and fro rocking test where I held wheel at 3 & 9 and then 6 and 12 and pushed and pulled. Things seem very tight this way. Next, I did a move where I turned the wheel right and left (as you would a steering wheel). When I stop the wheel abruptly, after a microsecond I feel a slight thud as the inner axle catches up. Does this make sense? Same on both sides.

I can tell you there is no leaking around wheel like the pics Naj sent.

James
63 230SL

[A Dalton]

When one hears a chirping bearing sound , it is usually a bearing that goes dry, rather than a bearing that has a res. of lube .
 First indication of chirping as turning is a dry "U" joint.
This is usually at low speed..
 At higher rpms, I have  seen same with a dry drive shaft center bearing.. these are easily detected by turning the shaft and listening with a stephoscope at bearing mount..

[J. Huber]

A couple more observations while I was under there. My cuff area is really oily. I have had the pinion seal replaced but its looks like its leakier than ever. I couldn't check oil level because I don't have the right wrench. Nor did local auto place. Is it anything special? I described it as a allen hex head (guessed 14mm.) Who can tell me for sure? Out of curiosity how much oil does the diff. hold? Then I can compare the amount on my floor!

Unrelated observ.: I notice where my rear muffler pipes are welded to the resonator section, there is black soot accumulating. Is this the sign of a leak?

James
63 230SL

[Ricardo]

Hey James
I think it is a 14mm. but you just need a 14mm or 9/16 bolt about an inch long and two nuts to lock together on the bolt and then you can use a 14mm or 9/16 socket on your new tool. I welded my nuts together [:0]so they wouldn't come off, but it should work to just tighten them well.
The diff level should be just below the hole (pinky feel) with the car on the ground. If you let the axle tubes hang down, you will overfill the diff. and then it will leak out your pinion seal. Make sure the little vent tube on the top of the diff. is clear, as the diff. will build up pressure and force oil out the seal if the vent is blocked. They unscrew, and have a little felt thingy on the top that gets plugged with dirt.
If I was a betting man, I'd bet the  black soot was a leak, sometimes it starts as a pin hole and after a while it sounds really cool. I was disappointed when I installed my new steel exhaust system

Richard

[J. Huber]

Decided to crawl under there and check things further. I began by making my first homemade Pagoda tool to get differential plug out. A variation on Ricardo's. I used an old 9/16 bolt and some vice grips... Thanks R


Download Attachment: tool.jpg
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Once I removed the plug, oil literally streamed out. It was obviously overfilled. It just kept coming...


Download Attachment: overfow.jpg
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In fact, to get to finger-dippin' level, I had to use a rubber tube to siphon a bunch out. I also spotted the vent while I was under there. It was caked with 40 years of crud...


Download Attachment: vent.jpg
63.92 KB

I managed to clean it off and got the cap off. It seemed to be crimped on there but I got it off. And inside was that little filter. Cleaned it as best I could and put it all back together.

I am very curious to see if my differential leaks will slow down after this procedure. I cleaned things up -- and last I checked not a spec of oil... Of course, this may have nothing to do with my mystery high-pitched squeal. But it still was fun getting my hands dirty!

James
63 230SL

[saygold]

Re: pagoda tools
I got a long 14 mm bolt and bent it over in a vice.  I have made several others as well for different sizes.

saygold

1966 230SL (euro) 4-speed manual

[saygold]

Oops!  Mice = vise

Saygold

[Malc]

Sometimes front disk brake pads will make this noise too. Especially if they are a little "sloppy" in the mounting area.

Would check this if the wheel bearings are ok. New pads are cheaper and easier to replace than wheel bearings...

Just a thought
Malc

[Ben]

James I have found similar noises over the years and my guess is that you may have to adjust the front wheel bearings and lubricatre them. Also if the front discs are worn, even slightly, you may have to remove the pads and chamfer the edges all round. They can drag on this disc and squeak !

Regards,
Ben in Ireland.
'64 230SL 4sp.

[J. Huber]

Ben, when you say adjust & lube front bearings, what dost thou mean exactly.

Another question, would a whistle caused by brake pads or discs occur without actually braking? I am familiar with the kind of brake squeel that occurs near to stopping. This one is not that -- its more faint and higher pitched and seems to occur as car veers slightly.

James
63 230SL

[A Dalton]

If your wheel bearings are loose, the wheel can cock out of plane when side force is applied to wheel [ like turning force]..
 This allows the rotor to no longer be parallel to the brake pad/caliper and can cause the outer edges of the pads to contact the rotor without brake pedal activation.. which could be your noise..
.. a quick test is to cut the wheel a little opposite the turn and see if noise stops....but your best bet is to jack the car and adjust the bearings and then go retry the car..
 Do both sides cuz a loose bearing on the right side can cause a noise in a left turn and visa/versa..