Rotational brake squeak?
05-29-2005, 12:58 PM
#1
User
Thread Starter
Rotational brake squeak?
I noticed a small number of 'squeak' post's over the last 6-7 months with no definitive cure.
Some were looking at pulley, A/C compressor, wheel, brake pad, rotor, or shaft issues -by location of squeak.
My issue started after I was forced into some 3 inches of flowing water at about 15mph where a pothole of San Andreas proportions was hiding. It gobbled the front end (went down by the bow), lifted the tail end (and since aforementioned pothole was on a slight curve, but, of course!) and spun it to the outside of the curve by about 2-3 feet. Essentially, Pattycakes almost came to a complete stop, lost the front right splash guard and broke the front spoiler, again. After inspecting her thoroughly that day, there were no measurable tweaks to the suspension/steering, pan, crossmembers, A arms, bodylines, hood lines or door lines. No frame abrasion either.
Braking is straight and true regardless of speed and brake pedal force. Absolutely no pulling. She tracks straight down the highway with no effort on the wheel other than in major truck wheelpaths on the Interstate.
However, I have developed that light squeal common to sHARKs after a car wash or wet weather runs. Since it was wet for several days I ignored it. After that I tried the medium and hard braking method for eliminating minor brake squeal after a water dousing. No Joy.
I have since pulled all the wheels for a digital runout check, had all the rotors faced -still within limits -, and flat surface sanded the pads to remove high and low spots - yep, I mic'd them afterwards for uniform thickness- .
I flushed the system and replaced the brake fluid. While on the blocks I ran the the rears from 0-20 mph 'indicated' with and without wheels/tires mounted, and spun the fronts with and without wheels mounted as fast as I could by hand.
No squeak just the slight barely audible 'brushing' sound of the slightest of pad/caliper drag.
When I hit the streets the squeak returned and seems to get louder when I make right turns though not during lane changes.
The squeak disappears over 35-40mph but I figure engine and road noise is hiding it. I've also tried high speed runs with engine only slow downs to see if one wheel/caliper/rotor gets hotter than the others. No Joy...
Also checked spring perches for rubbing -off center-, wheel bearings... inner & outers', and every concievable bushing and mount, crossmember for wear, shrinkage, or, movement. No Luck!.
I'm frazzeled.
Ideas anyone?
Some were looking at pulley, A/C compressor, wheel, brake pad, rotor, or shaft issues -by location of squeak.
My issue started after I was forced into some 3 inches of flowing water at about 15mph where a pothole of San Andreas proportions was hiding. It gobbled the front end (went down by the bow), lifted the tail end (and since aforementioned pothole was on a slight curve, but, of course!) and spun it to the outside of the curve by about 2-3 feet. Essentially, Pattycakes almost came to a complete stop, lost the front right splash guard and broke the front spoiler, again. After inspecting her thoroughly that day, there were no measurable tweaks to the suspension/steering, pan, crossmembers, A arms, bodylines, hood lines or door lines. No frame abrasion either.
Braking is straight and true regardless of speed and brake pedal force. Absolutely no pulling. She tracks straight down the highway with no effort on the wheel other than in major truck wheelpaths on the Interstate.
However, I have developed that light squeal common to sHARKs after a car wash or wet weather runs. Since it was wet for several days I ignored it. After that I tried the medium and hard braking method for eliminating minor brake squeal after a water dousing. No Joy.
I have since pulled all the wheels for a digital runout check, had all the rotors faced -still within limits -, and flat surface sanded the pads to remove high and low spots - yep, I mic'd them afterwards for uniform thickness- .
I flushed the system and replaced the brake fluid. While on the blocks I ran the the rears from 0-20 mph 'indicated' with and without wheels/tires mounted, and spun the fronts with and without wheels mounted as fast as I could by hand.
No squeak just the slight barely audible 'brushing' sound of the slightest of pad/caliper drag.
When I hit the streets the squeak returned and seems to get louder when I make right turns though not during lane changes.
The squeak disappears over 35-40mph but I figure engine and road noise is hiding it. I've also tried high speed runs with engine only slow downs to see if one wheel/caliper/rotor gets hotter than the others. No Joy...
Also checked spring perches for rubbing -off center-, wheel bearings... inner & outers', and every concievable bushing and mount, crossmember for wear, shrinkage, or, movement. No Luck!.
I'm frazzeled.
Ideas anyone?
Last edited by John Struthers; 05-29-2005 at 02:44 PM.
05-29-2005, 02:24 PM
#2
John,
When you checked the wheel bearings was Pattycakes jacked up or was she at full load? If one individual bearing was damaged, would the centering still be off? It really does sound like a left side bearing.
Dennis
When you checked the wheel bearings was Pattycakes jacked up or was she at full load? If one individual bearing was damaged, would the centering still be off? It really does sound like a left side bearing.
Dennis
05-29-2005, 02:40 PM
#3
User
Thread Starter
Dennis,
I did the 'loaded axial wiggle', not to be mistaken for the Oklahoma State Dance,
and could get neither a click, clunk, or wiggle,
not to be mistaken for our current U.S. Foriegn policy.
Due to steering gear movement (unloaded) resulting from inputs at the tire/wheel I simply checked the races and bearings for surface imperfections.
I'll recheck the fronts again anyhow.
I was almost hoping the calipers were twisted at the mount points, but that's not it either...Hmmm.
Thanks as usual.
I did the 'loaded axial wiggle', not to be mistaken for the Oklahoma State Dance,
and could get neither a click, clunk, or wiggle,
not to be mistaken for our current U.S. Foriegn policy.
Due to steering gear movement (unloaded) resulting from inputs at the tire/wheel I simply checked the races and bearings for surface imperfections.
I'll recheck the fronts again anyhow.
I was almost hoping the calipers were twisted at the mount points, but that's not it either...Hmmm.
Thanks as usual.
05-29-2005, 02:55 PM
#4
John,
Since the Okie state dance is a "square dance" your bearings are in big trouble. Think you can teach them to do se do?
May want to do a rolling check to see if it settles at one point.
Dennis
Since the Okie state dance is a "square dance" your bearings are in big trouble. Think you can teach them to do se do?
May want to do a rolling check to see if it settles at one point.
Dennis
05-29-2005, 04:44 PM
#5
User
Thread Starter
Will do.
Thanks for setting me straight on the Square Dance...
with my Television upbringing I thought Square Dancing was the Yiddish Marital Dance for Washington/Oregon state aka Seven Brides for Seven Lumberjacks..er, Brothers.
Drove Zack's 81' the other day -senior prank day- and he took my pick-up those idiots were tearing up the Junior/Sophmore cars.
The 81' doesn't seem to have the oomph of my 82' but that 81 is very smooth and talk about Quiet!
No squeaks or rattles at all.
I have work to do...
Thanks for setting me straight on the Square Dance...
with my Television upbringing I thought Square Dancing was the Yiddish Marital Dance for Washington/Oregon state aka Seven Brides for Seven Lumberjacks..er, Brothers.
Drove Zack's 81' the other day -senior prank day- and he took my pick-up those idiots were tearing up the Junior/Sophmore cars.
The 81' doesn't seem to have the oomph of my 82' but that 81 is very smooth and talk about Quiet!
No squeaks or rattles at all.
I have work to do...
05-30-2005, 06:39 AM
#6
Rennlist Member
Thorough as you were, I'm sure you wrestled out that ugly spring in the calipers to smooth and lube the sliding surfaces - and cut a slight chamfer on the pads with a favourite 'mill bastard' file ....
05-30-2005, 12:55 PM
#7
User
Thread Starter
Garth I did the chamfer on the pads when new -leading edge-.
There was still a miniscule bevel remaining after flat sanding. Hmmm
The spring might be the culprit, used rubber cement in lieu of the silicon lube
after I developed a wierd almost metallic chattering noise upon original install
-backing plate(?)-.
Thanx for the idea.
There was still a miniscule bevel remaining after flat sanding. Hmmm
The spring might be the culprit, used rubber cement in lieu of the silicon lube
after I developed a wierd almost metallic chattering noise upon original install
-backing plate(?)-.
Thanx for the idea.
