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Thickness of brake rotor
I have a 2000 GTP.
What is the thickness of the brake rotor when new ?
What is the minimum thickness that you can have to have them machined?
Are there any suggestions on which major brand name to use as a replacement (Delco, etc)?
Any hints on doing a brake job myself?
What is the thickness of the brake rotor when new ?
What is the minimum thickness that you can have to have them machined?
Are there any suggestions on which major brand name to use as a replacement (Delco, etc)?
Any hints on doing a brake job myself?
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Comments
2000 Pontiac Grand Prix
Component Specifications
Front Brakes:
Rotor Thickness (new) 32.2 mm, 1.27 in
Minimum Rotor Machining Thickness 31.7 mm, 1.25 in
Rotor Discard Thickness (see note) 30.7 mm, 1.21 in
Maximum Lateral Runout 0.080 mm, 0.003 in
Maximum Scoring 1.50 mm, 0.059 in
Thickness Variation 0.013 mm, 0.0005 in
Important: All brake rotors have a discard dimension cast into them. Replace any rotor that does not meet this specification. After refinishing the rotor, replace any rotor that does not meet the minimum thickness after refinish specifications.
Harry
I don't suppose anybody "opens up" brake shoes any more, either. keeps the fiber count under control for more years of heavy breathing, LOL.
Brake Rotor Refinishing
Do not refinish brake rotors when performing routine brake maintenance such as replacing worn disc brake pads. Refinish a rotor only under the following circumstances:
There is a complaint of brake pulsation.
There is scoring greater than 1.5 mm (0.060 in).
All brake rotors have a minimum thickness dimension cast into them. This dimension is the minimum wear dimension and not a refinish dimension.
Important
Do not use a brake rotor that, after refinishing, will not meet the specifications shown on the rotor. Always replace the rotor with a new rotor.
The front rotor is two plates with a honeycomb seperating them. It is 1.3125 thick. The two plates are quite thin about .250 to .3125 thick.
The rear rotor is a single plate.
I agree about only machining the rotor when they are badly scrored as the new pads will quickly wear to match the shape of the rotor.
The front rotor is two plates with a honeycomb seperating them. It is 1.3125 thick. The two plates are quite thin about .250 to .3125 thick.
The rear rotor is a single plate.
I agree about only machining the rotor when they are badly scrored as the new pads will quickly wear to match the shape of the rotor.
Grand Prix front rotor specs are the same from 1998 to 2003, as per the G.M. factory manuals:
original thickness = 1.270"
minimum machining thickness = 1.250"
discard thickness = 1.210"
lateral runout = .002" maximum
thickness variation = .0005" maximum
Rotor thickness is measured as overall thickness, about 1" in from the outer edge. Suggest you have your micrometer calibration checked.
I measure the rotor as 1.3125" including the honeycomb and that after 100,000 KM of use.
Evidently I am measuring it wrong.
How do you measure it so it falls within the factory parameters.
The reason I ask is because when I go and buy a third part rotor I want to make sure it is the correct thickness. I have been caught to many times by buying parts that are supposedly replacement but when I get everything torn down and try to fit the replacement part I find it doesn't fit.
I suspect you also rotate the rotor and measure for minimum thickness, inasmuch as the surface is machined and supposedly flat and plumb, and the minimum useful thickness is the most magic number if you're checking brakes.
if you're chasing pulsing or driveability/brakeability issues, you would use a pin caliper on a frame and look for delta-measurement, aka "runout", which indicates lack of flatness... which would be warpage from overheating in use.
notice I do not claim to be a tech in this field. alcan and oldharry, among others, certainly are. I have learned enough to know when I'm being strung along by somebody who wants my signed check, as opposed to somebody who wants me back for other work for years to come.
Another note on cheap parts:
I replaced lower ball joints on a '92 G-20 van (Chevrolet) today. There were replacement ball joints of unknown origin on the vehicle that the bearing portion of the ball had broken into six segments on the right side of the vehicle. The left had chips missing around the upper edge of the ball. Apparently the pin rotated in the ball instead of the ball in the housing, and when there was enough clearence from wear, road shock started breaking the sintered ball. I have never before seen damage like this in a ball joint where the vehicle did not come in on the hook. My customer has ony owned the van for six months, so the source of parts is unknown.
Harry
It seems there are two types of pads for the brakes a "Ceramic" pad at $174 for a set for both wheels ("Ceramic" is evidently original equipment) and a Delco pad which is $90.
When you get a price from the dealership for a brake job they always include the "Delco" set.
I had to pay a additional $36 (the difference in their cost price for the two) to get a upgrade to the "Ceramic".
I would never have known about the two types of pads if I hadn't talked to the parts department before I talked to the service department.
two things I don't want to cheap out on... steering and brakes.
I also find the service advisor is aware of the "upgrade" parts possibilities, for some mystical and unexplainable reason. they always know if there is a "gold" option for a service. darned if I can figure out why............