Originally Posted by machine.gun.kelly
It's not a structural thing at all...
1. grinding on aly aluminum removes the corrosion protection off of the part. Granted a small area, but still a source for corrosion. It is not a question if it will corrode, it's a question of long it will take for it all to corrode away. And, if you are grinding away at it, I'm sure that you don't have the capabilities of aluminum corrosion protection...neither chemical conversion coating nor anodizing.
2. It is no longer OEM and irreversibly damaged. Damaged...see #1. This is more for the car collectors than for anybody else or the short term minded...
3. The photo shows an adapter...which means there is one more joint that will fail...ie come loose or leak. Very bad practice to have extra joint in any hydraulic system...especially a safety system like the brake system.
4. It shows that you don't care about doing things right, just doing things fast...not something I aspire too.
The only reason it doesn't fit is because it has to be thicker to accept the M10X1.0 hydraulic fitting...
Since we're numbering things now...
1. It is highly doubtful that grinding a few thousandths off the edge of this area would result in corroding thru the 3/8-1/2" of aluminum below to the point of presenting any failure risk. Also consider these cars are generally not operated in conditions where calipers are exposed to road chemicals that would facilitate corrosion at any significant level. The engine bay of our cars is full of unpainted/untreated aluminum and we're not seeing corrosion failures there.
2. I can see areas of exposed aluminum at other edges in the photo from shelf/box wear. How are these areas any different with regard to corrosion potential from where you would machine off a small amount on the bracket?
3. Since this is a Lotus OEM part how did Lotus make it fit? Filed the edges at the factory most likely from other things I have seen on these handbuilt cars.
4. I do agree with you that a direct line fitting here is safer and less prone to leak than the banjo fitting with copper crush washers, but again that's what Lotus/AP spec'd here and I'd venture to guess there are countless cars running with this banjo setup, many of which are running in very arduous duty track environments without any issues.
5. As far as originality I have personally done rotisserie restorations on two concours show cars. I have never had a judge look at the back underside of a part, remove a brake line, and take points off for an area that had 20 thousandths machined off.
6. I don't understand your argument that filing off the edges here to fit the OEM Lotus supplied banjo fitting would make the part "no longer OEM" when you are at the same time advocating a different non-OEM fitting adapted from the S260 be used instead which was not OEM as Lotus supplied it with this caliper to the OP.