stphers
Well-Known Member
Anybody have a strut available or working on that area that can measure something for me. Want to know the bolt spacing for mounting the brake calipers?
Thanks, Rick
Thanks, Rick
Measurement needed
- Thread starter stphers
- Start date
I can provide that dim from my disassembled 3.0 struts if you'd like. Just give me a few minutes to run out to the garage.
Just to be certain, you mean this dim?
Just to be certain, you mean this dim?
78.5 inner to inner holes
Trivia: early 2800CS uses m8 wired locking bolts on the steering arm, 3.0CS uses 10mm.
I measured it a few different ways, and am coming up with about 89mm center to center. The pic looks skewed, but the caliper is actually in the center of the hole (as close as I can eyeball it). Hope this helps. FYI, the m8 and m10 locking bolts are on sale at WN right now.
Last edited:
Can you measure from inside edge of hole to outside edge of other hole?
stphers
Well-Known Member
Thanks guys, that is what I need. fooling around with 944T or 928 calipers to see what I can make happen
Thanks and all the best of the season to you all, Rick
Thanks and all the best of the season to you all, Rick
Good idea. I can try that, but it will still be by eye. I don't think I have a caliper with points in the same direction. But I should be able to confirm precision.
Measure outside to outside and then subtract one hole diameter measurement.
Just to close the loop on this, I measured per Tom @Mot27cars method - twice. The bolts should be 10mm, yet my threaded holes measure about 10.50mm thread to thread. The out to out measurement is 99.75mm.
99.75mm - 10.50mm = 89.25. However, if you "correct" such that the threaded holes should technically read 10mm, you might say that a corrected version of the formula is:
99.25mm - 10.00mm = 89.25. Same results. So I'd suggest that the center to center on these holes might well be 89.25mm.
Measuring "10.5 mm in an m10 hole " tells me something is not right.
Anyway your conclusion still stand, the 89.25 mm should be correct approach (my brake calipers are still on, otherwise I would have measured mine as well in service of your request)
I can only find 10.5 mm as a logical answer if you measure like this: on the outside surface, trying to estimate the outer circumference (which is quite inaccurate, and you should avoid)
An M10 has 8.5 mm when measuring a nut on its internal dimension. This is the best way to determine metric fastners.
Following table gives the Metric name, it's standard (not 'fine'!) pitch, and the hole diameter (see it as a cilinder with this dimension; it can fall clean through it)
Anyway your conclusion still stand, the 89.25 mm should be correct approach (my brake calipers are still on, otherwise I would have measured mine as well in service of your request)
I can only find 10.5 mm as a logical answer if you measure like this: on the outside surface, trying to estimate the outer circumference (which is quite inaccurate, and you should avoid)
An M10 has 8.5 mm when measuring a nut on its internal dimension. This is the best way to determine metric fastners.
Following table gives the Metric name, it's standard (not 'fine'!) pitch, and the hole diameter (see it as a cilinder with this dimension; it can fall clean through it)
Attachments
Last edited:
Another way to measure the distance is to stick both short ends of your caliper in, slide to their max dimension inside the holes, read the value (x), and deduct 8.5mm. That is then your center to center distance.
(This assumes the threads are nicely cut according standard dimensions.
Were talking Germans and safety parts here, so I'm sure they were in spec when they left the factory.
If the threads are slightly big ( loose), then your center to center value may be off by that amount. You can check this by measuring the inner dimension of both threaded holes; they should be 8.5 mm for M10. If they are e.g. both 8.6 mm , it will mean that you have to subtract not 8.5 but 8.6 mm from (x)).
(This assumes the threads are nicely cut according standard dimensions.
Were talking Germans and safety parts here, so I'm sure they were in spec when they left the factory.
If the threads are slightly big ( loose), then your center to center value may be off by that amount. You can check this by measuring the inner dimension of both threaded holes; they should be 8.5 mm for M10. If they are e.g. both 8.6 mm , it will mean that you have to subtract not 8.5 but 8.6 mm from (x)).
Perhaps my assumption that the bolts that hold the caliper to the strut being 10mm is incorrect. But I assure you nothing is wrong (certainly not with my struts, and I don't think with my measurements either). Later I can go out and reference the orange parts books. Maybe they are 12mm bolts. Feel free to go out and measure these holes on your struts and let me know what they measure.
I've now measured the spacing on these holes six ways to Sunday. I think the OP's matter is reconciled.
Last edited: