Brake Discs

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Mondo7
Posts: 4
Joined: 14 Feb 2018 02:43
Location: Huntington Beach Ca,

Brake Discs

Post by Mondo7 »

I'm looking for the minimum thickness dimension for the front brake disc on my 1984 3-1/2 S.
Thanks
Norm
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Brake Discs

Post by mbmm350s »

Hi Norm,

As a first post I suspect there is much more to the story than your simple question :D

Question are the disks original Grimeca equipment or replacements/reproductions

The original Grimeca disks specification was 5mm for minimum thickness, someone will correct me if I am wrong.

I have some reproduction? disks sourced from NLM within the last few years that have a starting thickness of 5mm, this is not an issue.

Since this is a safety critical issue I think i would consider more the condition of the disk with respect to scoring and warpage
rather than the absolute thickness (within reason of course!). Scoring/warpage "may" be rectified by skimming again with care.

Original Grimeca disks have a hardened chrome coating that tends to wear off eventually with age and usage, unevenly in some cases
which causes brake flutter and an MOT advisory,

The following may be of interest:

viewtopic.php?f=4&t=1667

Mark
Mondo7
Posts: 4
Joined: 14 Feb 2018 02:43
Location: Huntington Beach Ca,

Re: Brake Discs

Post by Mondo7 »

Thank you for the reply.
The reason for the question was that scoring on one disc needs to be addressed; the discs are now on their way to a company in Michigan for grinding.
I was looking for the minimum thickness just in case the guy had a question about it.
Norm
mbmm350s
Posts: 666
Joined: 22 Jun 2018 10:18
Location: Reading UK
Location: Berkshire UK

Re: Brake Discs

Post by mbmm350s »

Hi Norm,

After grinding/skimming it is recommended to use a "soft disk pad". I don't like the terminology soft or hard, but anyway "less abrasive" might be a better term.
(such as EBC organic FAO76 for street use)

Again I am assuming you have the original Grimeca disks and calipers. If not you should check the pad specification with the disk manufacturer.

Mark
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