Vibration when brakes applied - Alfa Romeo Bulletin Board & Forums

  #1 (permalink)  
Old 04-09-2005, 11:57 PM
Registered User
 
Join Date: Dec 2004
Location: Morayfield, Queensland, Australia
Posts: 26
Vibration when brakes applied

Hi,
My 1984 Afetta sedan has been basically laid up for nearly 12 months and I re-registered it last week. I've noticed that, when I brake, there's a noise which sounds just like going over closely spaced corrugations on the road. I assumed it was rust on the rotors but that isn't the case. I also suspected a warped rotor but, having checked them, they're all fine and none of the calipers are loose etc. One other thing that has me thinking is that I suspected that there was an engine vibration which was apparent at about 1500 to 2000 rpm that wasn't there before - if I rev the car whilst stationary. I've started to wonder now if it could be the rear donut (the noise / vibration seems to come from the rear). My theory was / is that, whilst braking, the rear axle tries to rotate (by inertia I mean) and, in doing so, if the donut was damaged, would accentuate any noise / vibration by placing a strain on the coupling. It does seem as if the noise is about twice road speed. I haven't been under the car to check yet but I wondered if anyone agreed with this as a possibility ? Any suggestions (as always) welcomed !!
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 04-10-2005, 05:38 AM
muhraka's Avatar
Registered User
 
Join Date: Jan 2005
Location: Romania
Posts: 151
Send a message via ICQ to muhraka
try checking the gear box mounts as well
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 04-10-2005, 06:00 AM
papajam's Avatar
Trained Professional
Platinum SubscriberAdministrator
 
Join Date: Feb 2003
Location: New Jersey USA
Posts: 13,277
Does the nature of the vibration change if you brake while in neutral or with the engine switched off? Also, if braking with just the handbrake is the vibration still there?
__________________
Jim

Series 1 Euro 1750 GTV
Series 2 USA 1750 GTV
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 04-10-2005, 01:29 PM
Registered User
 
Join Date: Dec 2004
Location: Morayfield, Queensland, Australia
Posts: 26
Braking in neutral

Hi
Yes, still there in neutral but I'm not sure it's quite as bad.
Good point about if it does it with the enguine off and coasting - haven't tried that yet - I will today !
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 04-13-2005, 05:46 AM
Registered User
 
Join Date: Mar 2005
Posts: 28
Hello Gerry,

Try looking at the condition of the centre bearing and also the rubber donuts. If they are fine check the condition of the bearings in the clutch housing, but I'll do this last as it involves taking the clutch housing out.

Hope this get you thinking

Regards,

Julian
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 04-16-2005, 01:52 AM
Registered User
 
Join Date: Dec 2004
Location: Morayfield, Queensland, Australia
Posts: 26
An update

Hi again

Thanks for the suggestions - much appreciated.
An update is that I did, in fact, try coasting, engine off etc and the vibration is still there. I'm assuming, by this being the case, that it has to be brake related (?). I've examined the front discs and found the offside rotor has strange 'patches' on the surface in a couple of places - almost like faults in the metal - except I suspect they may have been caused by the pads staying on the disc whilst the car was laid up for the past 12 months, only moving a couple of times and not being driven as such. What threw me was that it seemed, even to a passenger, that the noise was coming from the rear but the rear rotors are perfect, although getting to a stage of needing replacement due to thickness wear. I suppose, pain as it is, I'll only confirm my suspicions by changing the front rotors. Not sure about the centre bearing but I could check it just in case, wheel bearings are all fine, although a couple need adjusting. I really do appreciate the interest, response and time taken by you guys in responding with suggestions, again, my thanks.
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 04-16-2005, 03:51 AM
papajam's Avatar
Trained Professional
Platinum SubscriberAdministrator
 
Join Date: Feb 2003
Location: New Jersey USA
Posts: 13,277
Yes, since the vibration is still there when the engine is switched off, the drivetrain has been eliminated and points to the brakes as the source of the vibration. But before shelling out for new front rotors, try braking using only the handbrake. If the vibration is there, the problem is in the rear; if no vibration, it's the front.
__________________
Jim

Series 1 Euro 1750 GTV
Series 2 USA 1750 GTV
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote Quick reply to this message
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Alfa Romeo Bulletin Board & Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.



Thread Tools
Display Modes

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off










Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Copyright 2002-2011 AlfaBB.com All Rights Reserved.



SEO by vBSEO 3.3.2