Fitting a new disc brake system to our Mini and when I pumped grease into the lower ball joint grease came out a small hole behind the disc as seen on attached photos.

Has anyone ever came across this issue and suggestions on what to do.





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that's to grease the disc so they don't squeak. Just joking, isn't it a bolt hole for guard?

There is no thread in the hole.

No, the guard if fitted just mounts on the 2 caliper mounting lugs and the steering arm. If hole is threaded put a grub screw in. Or tap it first.
No idea why that hole is there, it's not on original hubs, or aftermarket ones I bought.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

I think i’ve seen this before - i think some disc hubs had blank holes in them where the holes would be on a drum hub to hold the back plate on- dont know why though.

To fix it, i’d tap and grub screw plug it.

A couple of plugging options if you don't want to tap the hole. Years ago we used to plug holes in steel hydraulic manifolds with hardened steel balls (ball bearings). By tests we found a 0.250" diameter ball driven into a 0.242" diameter hole would withstand better than 6000 PSI. The same ball driven into a 0.249" diameter hole was good for 3500 PSI. Nowadays hydraulic manifolds are commonly plugged with Koenig expander sealing plugs which maybe another option http://www.schiltec.com.au/

Since there will be little or no pressure involved, a ball with a couple of thou interference should plug the hole forever.

I'd be more inclined to contact the supplier and say "WTF?"

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did I tell you that I won a trophy?

Thanks for your replies. I have contacted the supplier an I believe he wants to replace them.

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