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precise size of front brake pistons

PostPosted: Tue Jul 12, 2022 2:42 pm
by HardTop
Has anybody got the definitive dimensions for the front brake pistons primarily the diameter .
The tolerances on this dimension are also of interest

Thanks in advance for any info or sources

Re: precise size of front brake pistons

PostPosted: Tue Jul 12, 2022 6:05 pm
by mbell
What car/calipers? Elan v +2 had different brake setups on the front.

Re: precise size of front brake pistons

PostPosted: Tue Jul 12, 2022 6:20 pm
by Billmack
Id say plus or minus .0005 or 7 inches from the nominal size

Re: precise size of front brake pistons

PostPosted: Wed Jul 13, 2022 11:07 am
by HardTop
1970 elan s4
front caliper are I believe Girling 14LF

values so far
48.1 mm
OR 1 and 7/8 inches = 47.625 mm
real values and tolerances would be appreciated

Re: precise size of front brake pistons

PostPosted: Wed Jul 13, 2022 11:57 am
by 69S4
I have 48.05mm on two pistons - one new, one used.

Re: precise size of front brake pistons

PostPosted: Wed Jul 13, 2022 12:10 pm
by rgh0
I measured 6 original pistons in good condition with no significant wear with a calibrated quality micrometre with zero error at 50.00 mm

Measurements were 48.10 mm +/- 0.02mm

cheers
Rohan

Re: precise size of front brake pistons

PostPosted: Wed Jul 13, 2022 12:36 pm
by 2cams70
Any reason why this dimension is important to you?

Re: precise size of front brake pistons

PostPosted: Thu Jul 14, 2022 2:21 pm
by Craven
As the originals are hard chrome plated I doubt the precise diameter is closely controlled. Surface finish more likely.

Re: precise size of front brake pistons

PostPosted: Sun Oct 23, 2022 10:02 am
by HardTop
Thanks for all the comments
I was interested because I suspected some new pistons I had were over size
It seems from the comments I was mistaken
Thanks again