Minimum Front Rotor Thickness

DOC4444 · **Posted:** Sun Oct 19, 2008 7:08 pm

2005 CRD: I have the full set of 2005 factory manuals, but they do not seem to include a spec for minimum front rotor thickness. It states that it is "cast or stamped into the hub", but I can't find it. There appears to be minimal rotor wear at 45K (almost no ridge), so I would be suprised if they can't be cleaned up by removing just a few thou from each side, but we got the Jeep at 17K, so I can't be sure that they have not already been machined.

Anybody have a minimum thickness spec?

Thanks,

DOC

jinstall · **Posted:** Sun Oct 19, 2008 7:28 pm

It is on the hat, you have to take the wheel off to see it. You can call a autoparts place and see if they have one in stock and ask then what the specs are. Most of the time they have it listed in the books and sometimes on the computer. You can also look online with a brake companies website. I checked Brembo but they do not have a photo.

DOC4444 · **Posted:** Sun Oct 19, 2008 8:48 pm

I cleaned the rust off the outboard surface of the hat on both front rotors, but, as previously indicated, can't see anything. If it's on the inboard side, I'll have to take the caliper brackets off to get the rotors off. I want to have all the parts I will need at hand to complete the job before I disable the vehicle. Normally, you can determine if you need to replace the rotors by measuring them before you take them off. I've never worked on a rig that did not have this info in the factory shop manual. Seems odd that it is not readily available.

Thanks for your reply.

DOC

ATXKJ · **Posted:** Sun Oct 19, 2008 9:21 pm

MY FSM section 5-7 Specifications

DESCRIPTION SPECIFICATION
Disc Brake Rotor

Diameter
Front
288 x 28 mm (11.3 x 1.102 in)
Disc Brake Rotor

Diameter
Rear
285 x 12 mm (11 x 0.472 in)
Disc Brake Rotor

Ventilated
Front
Max. Runout
0.102 mm (0.004 in.)
Disc Brake Rotor

Solid
Rear
Max. Runout
0.102 mm (0.004 in.)

DESCRIPTION SPECIFICATION
Disc Brake Rotor
Ventilated
Front
Max. Thickness Variation
0.015 mm (0.0006 in.)

Disc Brake Rotor
Solid
Rear
Max. Thickness Variation
0.018 mm (0.0007 in.)

Disc Brake Rotor
Ventilated
Front
Min. Thickness
26.0 mm (1.0236 in.)

Disc Brake Rotor
Solid
Rear
Min. Thickness
11.0 mm (0.4331 in.)

jinstall · **Posted:** Sun Oct 19, 2008 9:22 pm

Normally I would look on my Jeep but it is in the middle of the atlantic ocean, sorry. Try calling the local autoparts store they can pull one from the shelf and tell you what it says.

tjkj2002 · **Posted:** Sun Oct 19, 2008 9:28 pm

I have a specs book but sadly it's at work and I'm off till tuesday.

You will need to have the rotors turned if your going to install new pads,otherwise you will ruin the new pads,and anyplace that cuts rotors will measure them before turning to see if they can even turn them.By law they can not turn rotors that will end up under discard thickness so you will know pretty fast.Most places will also just measure them for you for no charge.

It's always been my belief you should always replace the rotors since when you turn them they will not disapate heat as well and warping/brake fade will occur faster.Sure you may only take off a few hundreths of a inch to get the rotors nice and flat but if you look at the pile of metal shaving's left after just taking off a few hundreths of a inch you'd think twice also,alot of metal is being taken off those rotors.

DOC4444 · **Posted:** Sun Oct 19, 2008 9:35 pm

Thanks ATXKJ!

DOC

mackruss · **Posted:** Mon Oct 20, 2008 11:52 am

I'm about due to replace both front and rear soon as i have a spongy break pedal at the moment and i'm hoping that i don't need to do any work on the master cylinder as the service manual says it could be due to a leak in the cylinder if the break pedal can be pushed to the floorboards.

Are most of you using the stock discs and pads when replacing or is there another brand that one can look at. Is it advisable to stay with the stock break setup rather than mismatching pads with discs etc.

tjkj2002 · **Posted:** Mon Oct 20, 2008 12:25 pm

mackruss wrote:

I'm about due to replace both front and rear soon as i have a spongy break pedal at the moment and i'm hoping that i don't need to do any work on the master cylinder as the service manual says it could be due to a leak in the cylinder if the break pedal can be pushed to the floorboards.

Are most of you using the stock discs and pads when replacing or is there another brand that one can look at. Is it advisable to stay with the stock break setup rather than mismatching pads with discs etc.

To help with a spoongy brake pedal............
http://jeepinbyal.com/cat-Brake_Accessories-6.aspx

Adding braided hoses in place of the rubber hoses will firm up your brake pedal,you'd be amazed by how much your stock rubber flex lines expand after a year or so.

Minimum Front Rotor Thickness

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