Brake Rotor drama
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Brake Rotor drama
The 69 I purchased arrived in NZ in June. All vehicle new to this country have to pass a stringent inspection before they can be registered here.
During the inspection the inspector deemed the front rotors to be outside spec according to his manual. I replace the front rotors.
Since getting the car registered I have driven a couple of 300 mile stints of which the car starts off with a good solid brake pedal, by the end of the journey pedal is hard on the floor!
After reading up about this issue on the forum and measuring the rotor run-out with a dial gage ( had 7 thou on one side, 5 on the other) decided to get the new rotors machined on the car. ( even though I was losing pedal and getting air in the system, I could not feel any pedal pulse)
I drove the car yesterday after having the rotors machined...terrible pedal pulse....whats going on?????
I measured the rotors after the machining less than 2 thou run-out still.
I removed the wheels again and measured ( the out side face of the rotor) still less than 2 thou run out?
Whilst rotating the rotor I noticed the inner brake pad pulsing in and out!
Some how during machining process the rotor has gained a variation in thickness.
As the outer surface has very little run-out only the inner seems to be affected??
Has anyone had this issue before??
Cheers
During the inspection the inspector deemed the front rotors to be outside spec according to his manual. I replace the front rotors.
Since getting the car registered I have driven a couple of 300 mile stints of which the car starts off with a good solid brake pedal, by the end of the journey pedal is hard on the floor!
After reading up about this issue on the forum and measuring the rotor run-out with a dial gage ( had 7 thou on one side, 5 on the other) decided to get the new rotors machined on the car. ( even though I was losing pedal and getting air in the system, I could not feel any pedal pulse)
I drove the car yesterday after having the rotors machined...terrible pedal pulse....whats going on?????
I measured the rotors after the machining less than 2 thou run-out still.
I removed the wheels again and measured ( the out side face of the rotor) still less than 2 thou run out?
Whilst rotating the rotor I noticed the inner brake pad pulsing in and out!
Some how during machining process the rotor has gained a variation in thickness.
As the outer surface has very little run-out only the inner seems to be affected??
Has anyone had this issue before??
Cheers
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Yes thats what I have concluded too. Trouble is probably have to pay another operator to correct the issue....
Thread Starter
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
The 69 I purchased arrived in NZ in June. All vehicle new to this country have to pass a stringent inspection before they can be registered here.
During the inspection the inspector deemed the front rotors to be outside spec according to his manual. I replace the front rotors.
Since getting the car registered I have driven a couple of 300 mile stints of which the car starts off with a good solid brake pedal, by the end of the journey pedal is hard on the floor!
After reading up about this issue on the forum and measuring the rotor run-out with a dial gage ( had 7 thou on one side, 5 on the other) decided to get the new rotors machined on the car. ( even though I was losing pedal and getting air in the system, I could not feel any pedal pulse)
I drove the car yesterday after having the rotors machined...terrible pedal pulse....whats going on?????
I measured the rotors after the machining less than 2 thou run-out still.
I removed the wheels again and measured ( the out side face of the rotor) still less than 2 thou run out?
Whilst rotating the rotor I noticed the inner brake pad pulsing in and out!
Some how during machining process the rotor has gained a variation in thickness.
As the outer surface has very little run-out only the inner seems to be affected??
Has anyone had this issue before??
Cheers
During the inspection the inspector deemed the front rotors to be outside spec according to his manual. I replace the front rotors.
Since getting the car registered I have driven a couple of 300 mile stints of which the car starts off with a good solid brake pedal, by the end of the journey pedal is hard on the floor!
After reading up about this issue on the forum and measuring the rotor run-out with a dial gage ( had 7 thou on one side, 5 on the other) decided to get the new rotors machined on the car. ( even though I was losing pedal and getting air in the system, I could not feel any pedal pulse)
I drove the car yesterday after having the rotors machined...terrible pedal pulse....whats going on?????
I measured the rotors after the machining less than 2 thou run-out still.
I removed the wheels again and measured ( the out side face of the rotor) still less than 2 thou run out?
Whilst rotating the rotor I noticed the inner brake pad pulsing in and out!
Some how during machining process the rotor has gained a variation in thickness.
As the outer surface has very little run-out only the inner seems to be affected??
Has anyone had this issue before??
Cheers
Looks like I have a resolve, have had the rotors re cut, it was a lathe operator issue, now we are well within spec, aoround 2 thou
Fingers crossed no more spongy brake pedal
