2004 Suburban Brake Noise???

Reply

  #1  
Old 11-21-10, 07:07 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Colorado
Posts: 34
2004 Suburban Brake Noise???

82k, 4x4.

Yesterday morning started to get a grinding sound when braking at low speeds. Sounded like metal on metal. I assumed that there were no wear sensors and the pads were down to metal.

Pulled the wheels and plenty of pad left on all sides. At least 1/16" to wear sensors.

Never had front pads changed. Rear pads done at 61k.

Listened at low speed, turning from side to side. None, so I presume that the wheel bearings are not the problems.

Ideas??

Also, anybody know what size torx I need to buy to remove caliper bolts?

Thanks
 
Sponsored Links
  #2  
Old 11-21-10, 07:20 AM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
Pads may be crystallized. This makes them as hard as the rotors (almost), and gives that sound of scraping. I believe the 7mm hex will fit. May be torx, but not sure of the size. Sam will chime in here shortly with more information.
 
  #3  
Old 11-21-10, 07:18 PM
ASE MASTER's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Aug 2010
Location: USA
Posts: 560
(Quote) 82k

(Quote) started to get a grinding sound when braking at low speeds. Sounded like metal on metal.

(Quote) Pulled the wheels and plenty of pad left on all sides. At least 1/16" to wear sensors.

(Quote) Never had front pads changed.

I see a pattern emerging with the above. How about you?

How are you defining all sides?
Outer pads only all around?
What about inner pads?
Could be worn down to nothing
better pull the calipers
and have a look see


82k and still no front pad replacement?
Think about it??


(Question) anybody know what size torx I need to buy to remove caliper bolts?

Off the top
of my head I
canít remember
havenít had enough
ďMarkers Mark yet
Should be a ďT-55Ē
if not work your way
down from there
 
  #4  
Old 11-21-10, 08:14 PM
ukrbyk's Avatar
Member
Join Date: Mar 2010
Location: USA/ Pacific NW
Posts: 3,189
well, let me put it this way. it is very odd to have rear brake pads replaced before front ones, due to engine/trannie weight on the front end.

i'd have those pads replaced and sooner than later.

grinding noise braking ONLY at low speeds or at high speed either?

i know those trucks, there's so much noise driving that it can conceal a lot of grinding. or a loud boombox.

anyhow, outside of parking brake, there's really nothing to grind back there. in brakes. there's much to grind in rear diff and axles.

i'd start with pads.

if you own a gm truck, simply buy set of torxe wrenches. you never know which one comes handy.

beware, their bolts are soft and strip fast.
 
  #5  
Old 11-22-10, 07:41 AM
Member
Thread Starter
Join Date: Nov 2009
Location: Colorado
Posts: 34
OK,

I have not pulled the pads yet.

I have visually checked both the inner pads and outer pads on both wheels and all four have plenty of pad left.

I presume if the rear pads went first, that either a proportioning valve is bad or the mechanic had a spqare set of rear pads he wanted to get rid of. Either way 82k seems like alot.

Next question. A Hayes manual says to open up the bleeder valve on the caliper before compressing the old pads, if you have ABS. I am presuming that this willo dump brake fluid out of the valve, so I should have some tubing ready?? Is this because the ABS valves are one-way so you can't force brake fluid back upto the master cylinder??

Jim
 
  #6  
Old 11-22-10, 01:22 PM
ASE MASTER's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Aug 2010
Location: USA
Posts: 560
(Quote) I have visually checked both the inner pads and outer pads on both wheels and all four have plenty of pad left.

(Quote) Next question. A Hayes manual says to open up the bleeder valve on the caliper before compressing the old pads, if you have ABS.

Stop right there Jim.

Youíre about to put the cart miles before the horse here.

Donít open any bleeders.

See your above quotes


Based on those quotes, tell us why you are compressing pads if there is plenty of pad left on the inner and outer shoes?

You appear to be directly contradicting your own quotes.

Clarify please!
 
  #7  
Old 11-22-10, 03:06 PM
Member
Thread Starter
Join Date: Nov 2009
Location: Colorado
Posts: 34
Hi ASE Master,

The first response I received yesterday pointed towards "Crystallized" Brake Pads.

Seems that this makes the most sense. With 82k and having to pull off the calipers to inspect, I would feel more comfortable replacing the pads.

Suburban brakes fine and doesn't pull to one side.

It does sound strange the rear pads needed to be replaced first.

What do you suggest as a course of action????

Jim
 
  #8  
Old 11-22-10, 03:27 PM
chandler's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Dec 2005
Location: USA
Posts: 39,968
One other thing I have mentioned in another thread, due to engine noise (cummins) and having the windows rolled up all the time, I didn't hear my rear brakes grinding their way to oblivion. Finally felt it one day and ordered new rotors and pads. Inside (piston side) was worn down to the honeycomb. On a dodge dually that's almost 3/8" of steel gone!! Only a few miles until it would have torn something up bad.
Sam, the tolerances on my wife's car were so close I had to compress the piston just slightly to get them over the new pads, although wear seemed negligible. I am sure it was "some".
 
  #9  
Old 11-22-10, 08:48 PM
ASE MASTER's Avatar
Banned. Rule And/Or Policy Violation
Join Date: Aug 2010
Location: USA
Posts: 560
Ok I understand now Jim. Thanks for explaining. You figure since youíre opening the calipers that you may as well change the pads. Iíll go along with that. Just make sure you use EBC, or Raybestos pads, and resurface the rotors.

(Quote) I have visually checked both the inner pads and outer pads on both wheels and all four have plenty of pad left.

(Quote) Suburban brakes fine and doesn't pull to one side.

Considering the above quotes, you may want to take the approach of de-glazing the current pads. To do this just hit them on a belt sander.

(Quote) A Hayes manual says to open up the bleeder valve on the caliper before compressing the old pads

They tell you to open the bleeder so you donít damage the ABS modulator. When youíre cranking down on the C-clamp to push the caliper piston back into its bore youíre sending brake fluid back into the system in reverse. This reverse flow of fluid can damage the ABS modulator. I never open the bleeders, because on an ABS system, opening the bleeders means opening a can of worms, and a new set of

Leave the bleeders closed. Just crank down on the c-clamp nice and slow. Donít use a lot of force and donít crank the clamp fast. Take at least 1 minute to get the piston back into the bore.
 
  #10  
Old 11-23-10, 03:25 AM
Member
Join Date: Apr 2006
Location: Floriduhhhhh Us of A
Posts: 611
Pull the rear brakes and check the PARKING BRAKE shoes you cannot see..........More than once I've seen these shoes go metal to metal in the drum part of the rear rotors
 
Reply


Thread Tools
Search this Thread
Display Modes
Posting Rules
You may not post new threads
You may not 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 On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 12:37 PM.