Parts Catalog Accessories Catalog Tech Info Tech Forums
 
  Search our site:    
 Cart  | Project List | Order Status | Help    
  Join us November 1st for Casino Night at the Pelican Parts Open House!
Benefiting LuMind - Research and Treatment for individuals with Down Syndrome
Go Back   Pelican Parts Technical BBS > 1- Porsche Technical Forums > Porsche 924/944/968 Technical Forum

Reply
 
LinkBack Thread Tools Rate Thread
Author
Thread Post New Thread    Reply
Registered User
 
Join Date: Feb 2008
Location: Escondido, CA
Posts: 31
Diagnosing Tire noise vs Bad wheel bearings (Goodyear Eagles)

Folks,

I would like to ask some help diagnosing road noise (1984 944). The car has Good year Eagles which I hear are noisy tires to begin with. In addition they may be several years old. The noise is consistent with what I've read here and other places about bad bearings, i.e. the noise is very low but increases dramatically with speed (50-70). Kind of a loud humming, sometimes it sounds a bit grindy, but not really.

I've been suspecting the bearings, but would really appreciate suggestions on how I can diagnose it more specifically. Car has only 67K miles, so bearings should not go bad in that mileage. Can't imagine that grease dries out or goes bad in 24 years ... maybe. (I don't have access to other wheels / tires else I'd swap and see).

Thanks!
__________________
Roland
84 944 ... 93 968 ... 89 Vanagon Syncro
[RIP: 911SC, 931, MGB, VW Bug, GTO, Sprite]
Old 02-28-2008, 08:39 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #1 (permalink)
Registered User
 
OnTheRun2's Avatar
 
Join Date: Sep 2005
Location: Middle TN
Posts: 267
Garage
You could try jacking up the car and spinning the wheels by hand. If your bearings are real bad you should hear them at that time. Or you could just get new tires and see if it goes away.
__________________
(Mae) Red '86 944na- gettting new paint soon.
(Abby) Black '86 944na- new addition to the family.
Old 02-28-2008, 09:07 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #2 (permalink)
Registered User
 
flash968's Avatar
 
Join Date: Jun 2006
Location: O.C. CA
Posts: 4,001
you could bring the car up here for detail day on the 8th and i could listen to it
Old 02-28-2008, 10:44 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #3 (permalink)
Registered User
 
Join Date: Feb 2008
Location: Escondido, CA
Posts: 31
That's a good idea flash, it isn't too far.
__________________
Roland
84 944 ... 93 968 ... 89 Vanagon Syncro
[RIP: 911SC, 931, MGB, VW Bug, GTO, Sprite]
Old 02-28-2008, 11:08 AM
  Recommend this thread for the PelicanWiki    Reply With Quote #4 (permalink)
Registered User
 
Tidybuoy's Avatar
 
Join Date: Jun 2003
Location: Fresno, CA
Posts: 5,025
Garage
I would jack the car up and spin the wheels and listen. For the rear wheels, once on jack stands, you could put the car in gear and listen. For the fronts you would just have to spin by hand. Your noise could be tires, bearings, or also brakes. Regarding bearings, grease can definatley dry out but unlikely unless the bearings were packed incorrectly - might not be a bad idea to repack them anyway. They could also just need tightening.

I just switched tires on my car to Bridgestone Potenza RE70's and their very noisy (from a different Potenza tire). I love the handling but they are loud and ride sitff - so tires can definately be your issue too.

Vern
__________________
Vern

'74 911 Coupe - Silber Metalic (963-93), PMO ITB Injection and Electromotive Management
'88 944 Coupe - Nougat Brown Metalic
'74 914 Targa - Light Gray 2.0
Old 02-28-2008, 12:18 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #5 (permalink)
Custom User Title
 
Dave L's Avatar
 
Join Date: Nov 2003
Location: Barrie, Ontario Canada
Posts: 2,954
wheel bearings will howl and will absoulty get louder as your speed increases. In a corner the bad bearing will be even louder. If its loud turning right its a bad bearing on the left side and vise versa. Either way I would do both sides.
Old 02-28-2008, 12:24 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #6 (permalink)
 
Now Available for Ordering:   101 Projects For Your BMW 3 Series 1982-2000  [more info]
Registered User
 
Join Date: Feb 2008
Location: Escondido, CA
Posts: 31
Dave,

Yes! The word howl definitely rings true.

Just went for another test drive.

At lower speeds 25-40 it is more of a rumble. At higher speeds, 55-70 it turns into more of a howl, with a very slight (almost imperceptible) metalic sound, although this could be some resonating. Volume grows with speed, exponential, not linear. Slight bias to the rear. And of course is definitely with road speed, not engine speed. I haven't noticed any left/right corner changes while doing some simple sway back and forth, this test probably deserves repeating with hard cornering.

Open to more ideas, but current plan would be to take Verns suggestion, jack it up and try some spinning. I'll probably unbolt the axles during this test as well. Various inspection (CV boots are in great shape, but who knows what is inside).
__________________
Roland
84 944 ... 93 968 ... 89 Vanagon Syncro
[RIP: 911SC, 931, MGB, VW Bug, GTO, Sprite]
Old 02-28-2008, 01:29 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #7 (permalink)
Registered User
 
Makis's Avatar
 
Join Date: Mar 2002
Location: London, UK
Posts: 398
Try to over inflate the tire and see if the noise changes. If there is no change chances are the noise is not cause by tires. Also does the noise sound from the rear center or can you pinpoint exact location left or right? Also if you have same size tires front back you can experiment with rotating the tires to observe how the noise is changing.
Old 02-29-2008, 02:45 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #8 (permalink)
Custom User Title
 
Dave L's Avatar
 
Join Date: Nov 2003
Location: Barrie, Ontario Canada
Posts: 2,954
To test the wheel bearings just grab the top of the tire and try to pull it side to side. If there is much movement you will know that its the bearings.
Old 02-29-2008, 03:40 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #9 (permalink)
Registered User
 
Join Date: Feb 2008
Location: Escondido, CA
Posts: 31
Ok, ran some tests:

To see if the tires could be the source, in addition to the normal tire pressure, I did test runs one test run at 24 lbs and one at 45 lbs tire pressure. There was no significant change in the noise with these variations in tire pressure.

There were no noticeable differences when cornering hard left of right.

With wheels in the air, 3 of the wheels are wiggling when I move them top to bottom. When I spin them, there isn't any alarming noise (except one). But then I didn't expect to hear anything remarkable since there is no load on the bearings. 2-3 of them had a dragging sound that is characteristic of the brake pads touching just a tiny bit. One of the wheels did have a funny sound, almost like a 'dry' wheel bearing, but who knows, I could be imaging this.

When I spin the rear wheels there isn't any remarkable sound that might indicate something with the axles or the trans, but then I am not sure if this type of test would reveal something in those areas.

Sounds like next step is remove the stuff to get at the bearings.
__________________
Roland
84 944 ... 93 968 ... 89 Vanagon Syncro
[RIP: 911SC, 931, MGB, VW Bug, GTO, Sprite]
Old 03-02-2008, 01:47 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #10 (permalink)
Registered User
 
flash968's Avatar
 
Join Date: Jun 2006
Location: O.C. CA
Posts: 4,001
bring it up here saturday
Old 03-02-2008, 01:49 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #11 (permalink)
Registered User
 
Makis's Avatar
 
Join Date: Mar 2002
Location: London, UK
Posts: 398
Tire noise is probably not then. The bearings could be the problem. There should be no movement when you wiggle them. The fronts can be adjusted but the rear bearings cannot at least on the later type that I have on my S2. I believe you have the bearings that are made out of more then one part and may be this type may allow some play but doubt it. May be you can re grease them if they are dry, but not sure this can be done on the rear bearings.
Old 03-02-2008, 03:40 PM
  Recommend this thread for the PelicanWiki    Reply With Quote #12 (permalink)
Old 03-02-2008, 03:40 PM
Reply

Thread Tools
Rate This Thread
Rate This Thread:

 



All times are GMT -8. The time now is 03:10 PM.


 
Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0
Copyright 2011 Pelican Parts - Posts may be archived for display on the Pelican Parts Website -    DMCA Registered Agent Contact Page
 

DTO Garage Plus vBulletin Plugins by Drive Thru Online, Inc.