| Author | Message | ||
     Nick Adlam Experienced User Username: crewes_control Post Number: 41 Registered: 12-2015 |
Evening Gents My rear disks seem to be showing some pulsation when braking- can feel it through the pedal when pulling up, especially at highway speeds. The fronts were machined about 8 months ago. Anyone know the minimum thickness of the disks?. I know they're 0.500" new, but can't find anything more. | ||
| Nick Adlam Experienced User Username: crewes_control Post Number: 42 Registered: 12-2015 |
Ohh, that should be "Disc"!- this is what happens when you've been in the IT industry for over 15 years!. | ||
| Paul Yorke Grand Master Username: paul_yorke Post Number: 1561 Registered: 6-2006 |
Hi Nick, not at my desk atm so can't give the measurement now. In general it's tricky to know what thicknes the disc will end up until you've nearly finished. The manual is pretty conservative though. On vehicle disc skimming is very successful and saves a lot of time and labour. For others, and at the risk of being boring, if the car sits around or you are doing less than 5000 miles a year it is a must to remove your rear brake pads at least every 24 months and ensure they are completely free to slide in and out with just your fingers. Visual checking or just squeezing the pin side of the pads is not enough. Seized or semi seized pads are the main cause of ruined rear discs. | ||
| Nick Adlam Experienced User Username: crewes_control Post Number: 43 Registered: 12-2015 |
Hi Paul Thanks for that. Will definitely use on-car machining. I'm just hoping there's enough "meat" on the discs to save the big replacement expense. Do the calipers and park brakes have to come off for on-car machining?, or are there ways to leave everything in situ?. cheers | ||
| Alan Dibley Experienced User Username: alsdibley Post Number: 12 Registered: 10-2009 |
"Do the calipers and park brakes have to come off for on-car machining?, or are there ways to leave everything in situ?." It depends on the machine. I have used one which did not need anything removed but the road wheel. I can't find any reference to minimum thickness in the manual. I must be looking in the wrong place(?). Alan D. | ||
| Brian Vogel Grand Master Username: guyslp Post Number: 1994 Registered: 6-2009 |
It has been years since I found the following somewhere in the technical documentation: Disc Brake Rotors New Rotor Thickness: 1.25 inches. Minimum thickness after skimming: 1.18 inches. As Paul has already noted, this is a very, very conservative "minimum thickness" figure, even when taking the weight of the car into account. Brian | ||
| Alan Dibley Experienced User Username: alsdibley Post Number: 15 Registered: 10-2009 |
Quote:- Disc Brake Rotors New Rotor Thickness: 1.25 inches. Minimum thickness after skimming: 1.18 inches. That is for ventilated disks on the front of later mchines. Shadow rears are all 0.5 inches, (I think). Alan D. | ||
| Nick Adlam Experienced User Username: crewes_control Post Number: 44 Registered: 12-2015 |
Hi Brian I was actually needing the minimum for the rear discs- they are solid and thinner than the fronts on my SS-1. The factory original thickness was 0.500". I think someone on the other RR forum mentioned 0.480" as a sensible minimum. What that sound about right?. | ||
| Nick Adlam Experienced User Username: crewes_control Post Number: 45 Registered: 12-2015 |
Hi Gents Just checked it all today- 0.400" minimum thickness stamped on the disk. According to my trusty micrometre, I have 0.080" of meat left on the bone. Phew!. | ||
| Patrick Ryan Prolific User Username: patrick_r Post Number: 291 Registered: 4-2016 |
Nice work Nick. Are you sure you didn't measure the outer most lip of the disc?  Just kidding, I did just that as an apprentice. |
