Grinding front brakes after rim and tire swap - SaabCentral Forums
*
Home Saab Pictures Saab Classifieds Saab Dealer Listings Saab Forum Saab Forum


Go Back   SaabCentral Forums > Saab 9-5 Mk.I, 1998-2009 > 9-5 Workshop

9-5 Workshop 9-5 Workshop (1997 to 2010) Technical Forum

SaabCentral.com is the premier Saab Forum on the internet. Registered Users do not see the above ads.
Reply
 
Thread Tools Display Modes
  #1  
Old 25th January 2010
davesh davesh is offline
Active Member
 
Join Date: Nov 2009                                                
Location: Ithaca, NY
My Saabs: 1999 95 2.3
Posts: 35
Default Grinding front brakes after rim and tire swap

Just changed from A/S on 16" wheels to M/S on 15" wheels for winter. On first trip around town there's quite a bit of grinding/groaning noise coming from the front wheels, but maybe more on the right side (passenger). This noise wasn't there on the A/S tires and wheels. This is at all speeds, and also maybe in reverse...

The M/S have noticeable cupping. 205/65/15 (1 of 4 brand new)

The A/S are 205/55, which is approx. 3% smaller diameter than OEM specs... Shorty after installing it snowed, and I noticed that the brakes lock-up when the brake pedal is fully depressed when trying to slide to a stop (causes judders). However, it seems that in snowless/iceless conditions, the lock-up doesn't occur.

The M/S rims were very dusty (old mud?) and had some rust before I put them on. Should I take them off and clean them? And also clean my rotors while I'm there?

Maybe the cupping of the M/S is causing this, or the ~3% difference in the 205/55's caused some permanent damage? It seems like a caliper is sticking... Maybe the change of tires wore out whatever amount of pads that I thought I had left.... ?

Any ideas?

Thanks

Last edited by davesh; 25th January 2010 at 11:57 PM.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 26th January 2010
Bubbaman's Avatar
Bubbaman Bubbaman is offline
Senior Member
 
Join Date: Jan 2009                                                
Location: Netherlands
My Saabs: MY01 9-5 Aero Sedan (T7Suited St 2+) LPG
Posts: 188
Default

15" too small for the brake calipers? Remember, when you break the whole unit heats up and expands! If you have a very small margin it could become no margin at all...
Be carefull here!
Reply With Quote Quick reply to this message
  #3  
Old 26th January 2010
gghh gghh is offline
Saab Lunatic
 
Join Date: Dec 2006                                                
Location: Hamburg Germany
My Saabs: BMW 530D Touring xDrive
Posts: 2,037
Default

If you have Aero front brakes, minimum required size is 16".
Reply With Quote Quick reply to this message
  #4  
Old 26th January 2010
davesh davesh is offline
Active Member
 
Join Date: Nov 2009                                                
Location: Ithaca, NY
My Saabs: 1999 95 2.3
Posts: 35
Default

Regular 2.3l turbo sedan. The tires should be within my specs, but they are mud/snows and the specs call for snows only with 195/65/15. So not sure if this matters so much?

Maybe someone installed non-oem parts or calipers?

I was using the star pattern, but I may have them over-torqued, as I made about 3 passes at the bolts. The tires have quite a bit of cupping... Thinking I may go back to the A/S in hopes of having functioning brakes.

Last edited by davesh; 26th January 2010 at 03:09 AM.
Reply With Quote Quick reply to this message
  #5  
Old 26th January 2010
GSBuilder GSBuilder is offline
Senior Member
 
Join Date: Jan 2009                                                
Location: Saint Paul, MN
My Saabs: 1999 9-5SE
Posts: 141
Default

15" is recommended for non-aeros like yours for winter wheels. I would take off the front wheels and inspect the rims for damage and also the calipers and rotors. Look at the pads as well, perhaps you sheared a pad and the fact it started when you switched tires is coincidental. Also look for uneven pad wear that would indicate caliper bushing wear. Your tire and wheels should not be making contact, this is an acceptable size combination for your car.
Reply With Quote Quick reply to this message
  #6  
Old 26th January 2010
Wulf Wulf is offline
Banned
 
Join Date: Apr 2006                                                
Location: NW Michigan - USA
My Saabs: 2011 Saab 9-4X 3.0i
Posts: 7,581
Default

The small difference in tire size shouldn't be causing any problems. Are the winter wheels original Saab wheels? Have you had these on your car before?

Take the wheels off and check to see if there is any wear on the outside of the calipers or inside of the wheels.
Reply With Quote Quick reply to this message
  #7  
Old 26th January 2010
MacNoob's Avatar
MacNoob MacNoob is offline
Saab Lunatic
 
Join Date: Sep 2006                                                
Location: chilly La Salle, MB.
My Saabs: 01 9-5 Wagon (RIP); 05 9-5 Aero (gone)
Posts: 4,991
Default

Sloppy tire changing practice can result in bent brake backing plates that rub on the rotors and make grinding noises.
Reply With Quote Quick reply to this message
  #8  
Old 26th January 2010
davesh davesh is offline
Active Member
 
Join Date: Nov 2009                                                
Location: Ithaca, NY
My Saabs: 1999 95 2.3
Posts: 35
Default

Not sure why, but the front pads are locked onto the front rotors. I put the wheels up and they spin, but the pads are grinding away ....

Going to switch back to the 16" 205/55's up front to see if it helps.

The 15" tires were on the car last winter, but I don't know if the wheels are Saab or not...
Reply With Quote Quick reply to this message
  #9  
Old 26th January 2010
tdrudd87 tdrudd87 is offline
SaabNut!
 
Join Date: Dec 2008                                                
Location: Michigan
My Saabs: 2002 9-3 SE 140kmi
Posts: 321
Default

Quote:
Originally Posted by davesh View Post
Not sure why, but the front pads are locked onto the front rotors. I put the wheels up and they spin, but the pads are grinding away ....

Going to switch back to the 16" 205/55's up front to see if it helps.

The 15" tires were on the car last winter, but I don't know if the wheels are Saab or not...
If you can spin it fairly easily by hand, they are normal. The hydraulics in the caliper cannot pull the pad completely from the rotor face, so when spun by hand they will sound to be dragging.

This is why old drag racers prefer drum brakes. They don't care much about repeated stopping power, and drums have springs to pull the shoes from the drum, eliminating friction.

The way you described juddering on ice/snow but not dry roads during hard braking sounds like ABS activation to me, not anything bad. This will make a buzzing noise and shivers in the brake pedal.

Check for contact wear on the system, and ensure the dust shields are not bent onto the caliper as others have said already. I doubt the wheel change will solve your issue.
Reply With Quote Quick reply to this message
  #10  
Old 26th January 2010
gghh gghh is offline
Saab Lunatic
 
Join Date: Dec 2006                                                
Location: Hamburg Germany
My Saabs: BMW 530D Touring xDrive
Posts: 2,037
Default

Check the brakes and check the length of your wheel bolts. Dont drive the car until you find and fix the reason.
Reply With Quote Quick reply to this message
  #11  
Old 26th January 2010
davesh davesh is offline
Active Member
 
Join Date: Nov 2009                                                
Location: Ithaca, NY
My Saabs: 1999 95 2.3
Posts: 35
Default

Thanks for all of your replies

Switched the front wheels back to the 16" 205/55's. The really loud grind and vibrations are gone now... Ha ha, but the front calipers maybe are seizing, or something, as the car feels like it's not coasting freely. This might be a suspension or steering issue, as going over bumps rocks the whole car forwards/backwards like something is giving out , but the MPG's have been going down. They went from ~24 to ~19 in the past month or so, and they're now at ~15 (although the car has lately been idling some in the driveway for repairs).

Quote:
Originally Posted by tdrudd87 View Post
If you can spin it fairly easily by hand, they are normal.
The rotors spin without putting in much effort, which must be good... However, after driving around town, there seems to be a very soft grinding noise has been coming from the right front wheel (but it's been there for some time it seems)... This is funny, because I noticed it before but thought nothing of it, and maybe putting on the 15's brought it to my attention?

When releasing the accelerator, the car jerks back a few times, but for a manual this is probably normal....

Quote:
Originally Posted by gghh View Post
Check the brakes and check the length of your wheel bolts. Dont drive the car until you find and fix the reason.
The bolts look OK. They have cone-washers (image) which seem to be properly seated. One note here, however. The right-front rotor seems to be missing the rotor set screw. I didn't notice it until moving on to the left-front side--so the right-front rotor rotates freely against the wheel hub, and I had to line up the rotor holes to the wheel hubs holes before mounting the wheel....
Attached Thumbnails
Click image for larger version

Name:	cone-washer.jpg
Views:	26
Size:	29.9 KB
ID:	16027  
Reply With Quote Quick reply to this message
  #12  
Old 26th January 2010
elefante72 elefante72 is offline
Active Member
 
Join Date: Oct 2009                                                
Location: NY
My Saabs: 2004 Saab 9-5 Arc Wagon
Posts: 58
Default

The rotor set screw isnt necessary, however it makes life easier. THat's an easy fix. Im more converned w/ the cupping as it may lead to a number of suspension problems. Is there cupping on the 16" tires also? If you are just seeing it on the 15" then I would measure the rims because you may not have 15" rims (common cupping reason rim/tire mismatch). If the cupping is happening on more than 1 tire and ONLY on the 15's than you probably have the wrong rim on there. If the rims are smaller than thought (say 14.5/14, then you could have easily damaged your breaking system. If it is happening on both, then there may be need for suspension parts, wheel bearings, and/or alignment.

The tire size diff of 3% shouldn't matter. I do that on mine too. Make sure when turning that they arent rubbing in the wheel well.

I would check that first.
Reply With Quote Quick reply to this message
  #13  
Old 26th January 2010
elefante72 elefante72 is offline
Active Member
 
Join Date: Oct 2009                                                
Location: NY
My Saabs: 2004 Saab 9-5 Arc Wagon
Posts: 58
Default

After I posted, I thought for a minute, and ran this on powerdog:

Specification Sidewall Radius Diameter Circumference Revolutions Speedometer Odometer Difference 205/55-15 4.4" 11.9" 23.9" 75.0" 845/mi 60MPH 10000mi N/A 205/65-15 5.2" 12.7" 25.5" 80.1" 791/mi 56MPH 9367mi 6.8% 195/65-15 5.0" 12.5" 25.0" 78.5" 807/mi 57MPH 9559mi 4.6%

WIS says rim offset should be:49 mm

So it appears that the tires you have on there (205/55) are outside of the recommended sizing by a good deal.

So please check the rim size and offset.
Reply With Quote Quick reply to this message
  #14  
Old 29th January 2010
davesh davesh is offline
Active Member
 
Join Date: Nov 2009                                                
Location: Ithaca, NY
My Saabs: 1999 95 2.3
Posts: 35
Default

Quote:
Originally Posted by elefante72 View Post
The rotor set screw isnt necessary, however it makes life easier. THat's an easy fix. Im more converned w/ the cupping as it may lead to a number of suspension problems. Is there cupping on the 16" tires also? If you are just seeing it on the 15" then I would measure the rims because you may not have 15" rims (common cupping reason rim/tire mismatch). If the cupping is happening on more than 1 tire and ONLY on the 15's than you probably have the wrong rim on there. If the rims are smaller than thought (say 14.5/14, then you could have easily damaged your breaking system. If it is happening on both, then there may be need for suspension parts, wheel bearings, and/or alignment.
I'll have to check the 15" wheels for the exact diameter. The cupping occurs on all four tires, and on both the 15" and 16" wheels. It's also worn very unevenly, seeming to be that every foot or so around the circumference--in addition to cupping--there has occurred wide swath of bald spot.

My best option right now is probably to bring it to a local mechanic, as I don't have much experience is diagnosing steering, suspension, alignment and brake issues...

However....

The right front side drags and pulls the steering to the right. Occasionally, the dragging in the steering in the right side will subside, and as it does this, it will shift to dragging on the left front side. This doesn't last too long and then it's back to dragging on the front ride side. (It feels like the steering is a ships mast, and it never it standing up straight, and instead is always leaning to one side or the other).

The parking brake seems to be OK. At the beginning of winter the parking brake froze up, and it took some hot water and rags to get it to release (since then I've had a chance to test the parking brake and it seems to work OK, and to be fully released).

Is there any way to reset the MPG and miles traveled on the SID? Pressing the Clear button does the job of resetting the MPG, however, the miles traveled still remains (although fluctuating around at 130-190 miles). My MPG is drastically low, something like 15 MPG, and after resetting it seems to keep going back to, and hovering back and forth around 14-15.

Right now my plans are for bleeding (using a syringe to pull out the fluid) the brakes and clutch hydraulics asap. (Although the max temp. tomorrow is forecast at 16F )... And while the wheels are off, the pad life should be visible (there is a soft grinding even with the old tires back on, but it disappears when applying the brakes... My hopes are that the pads are worn and it's the wear indicator that's been grinding?) BTW, is there a good way to check the inner pads without having to remove the calipers?

Cheers

Last edited by davesh; 29th January 2010 at 08:41 PM.
Reply With Quote Quick reply to this message
  #15  
Old 29th January 2010
GSBuilder GSBuilder is offline
Senior Member
 
Join Date: Jan 2009                                                
Location: Saint Paul, MN
My Saabs: 1999 9-5SE
Posts: 141
Default

Oh please get that steering diagnosed. That's not something you want to play with, it sounds like tie rod ends. When those fail, the car crashes.
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Bookmarks

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the SaabCentral 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:
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

Forum Jump


All times are GMT -4. The time now is 07:07 PM.



Powered by vBulletin® Copyright ©2000 - 2014, vBulletin Solutions, Inc.

top of page | sitemap | email us



copyright © 2003 - 2011 saabcentral.com, All rights reserved http://www.whiter.co.uk - valid xhtml - valid css
SaabCentral is an independently run website and is not affiliated in any way to Saab Automobile AB.


Garage Plus vBulletin Plugins by Drive Thru Online, Inc.