Author Topic: Torque on disc brake caliper bolts...64 230 SL.  (Read 3177 times)

Mike H

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Torque on disc brake caliper bolts...64 230 SL.
« on: October 12, 2019, 05:59:55 »
Hi,
To  restore the front brake calipers, I split the two  halves, which are held together by 2x17mm and 2x14mm bolts, on the Girling 17/3 version 3 model. These bolts are torqued in the factory and are not meant to be separated.
Can anyone give a correct torque for 14 and 17mm bolts on reassembly.
Thanks,
Mike.

Tyler S

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #1 on: October 12, 2019, 13:40:08 »
Here is a Metric bolt torque chart.
Determine the thread diameter, bolt class, and look up in the table.
1968 (67) 250sl. 4 speed manual. DB180 Silver
1955 220 Cabriolet A. White Grey
2019 E450 Wagon. Majestic Blue
1936 Ford PU Flathead V8. Creme on tan interior.
1989 Volkswagen T3 Westfailia Campmobile. Dove Grey (blue)

Mike H

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #2 on: October 14, 2019, 01:51:41 »
Thanks Tyler,
Regards,  Mike

johnk

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #3 on: October 18, 2019, 19:54:26 »
How do you determine the bolt class?
John Krystowski
Avon Ohio
1968 Euro 280sl under restoration
2016 Jag F-Type R sold june 2021
1950 Alfa Romeo 6C 2500 SS For sale
2008 E350
2007 GL 450
2019 BMW 540

EeVeeWee

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #4 on: October 18, 2019, 20:15:00 »
How do you determine the bolt class?

The class number must be shown at the bolts: 8.8, 10.9, 12.9, etc.
When it's not shown, then it's worse than 8.8.
Again something else.

Pawel66

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #5 on: October 18, 2019, 22:31:38 »
I am not sure, but you may need the black bolts, which is 12,9 class for calipers. You may want to check it...
Pawel

280SL 1970 automatic 180G Silver
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W121 190SL
G-class

swood1

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Re: Torque on disc brake caliper bolts...64 230 SL.
« Reply #6 on: October 19, 2019, 20:03:17 »
The bolts on your front calipers are actually 11.9 and M8 thread, it should say this on the head.  The head size across flats on mine are 14mm if this helps.
If you have split them you need to replace the small rubber seals between the halves. 
I was advised when re-assembling the calipers to the do the following which maybe of some help:-

1. Firstly, it is recommended you apply thread locker such as Loctite red on the threads before reassembly.

2. Tighten the bolts by hand just to ensure the halves match properly then torque up in two stages as specified below (you're basically torquing up the inner bolts prior to the outer):-

Fronts - if M8
Left to right, number the bolts with the nuts facing you 1-2-3-4
2-3-1-4  at 10ftlbs
then
2-3-1-4 at 26ftlbs

Rears - I believe are M7
Again numbered from left to right, 1-2-3-4
2-3-1-4 to 7ftlbs
then
2-3-14 to 17ftlbs

Hope this is helpful.  Dont hold me responsible if your brakes dont work...

250 SL (early), in bits. Triumph TR4a