altering brembo calipers?

[bugsoup]

Has anyone ever modified a caliper by machining a little off the outside (the surface closest to the wheel)?

Background: I have 996 front and rear brakes (calipers and rotors) and 16x6, 16x8 Design 90's. The rear setup should be fairly simple to fit, but the mockup of the front is giving me problems. On the oustide surface of the calipers, there is a step that increases the overall outside diameter to interfere slightly (maybe 1/16") with the inside of the wheel. The wheel's inner most material also happens to be a stepped to the inside towards the caliper.

Is it possible or safe to remove a bit of material from either the wheel or caliper to make them fit together? I am going to try to get some pictures to further explain the situation. In the meantime, if someone has understood my explaination or has done this, I'd be glad to hear what you have.

[Da1Duc]

Depends on the caliper, two things would concern me the most:

First the weakening of the caliper (ie from trimming it down) esp. if it is not steel!

Second the flexing (though minor) of the wheel.

Could you not trim the rotor a bit and move the caliper in?

Derek

[lightning bug]

I would definitely NOT remove any material from the wheel. As for the caliper, I'm not sure. Are you sure the rotors aren't going to give you a problem with the 16's? Its gotta be close.

[bugsoup]

At this point, the caliper and rotor fit, but they are touching around the perimeter of the caliper. Also, the rotor is all the way into the caliper (they are also touching). What should the clearance between the rotor edge and caliper be?

I definately understand the problems with clearancing the wheel. That I will not try. As for the calipers, it seems they would not be dangerously weakened by minor machining. They are shaped as if they were made to fit one particular wheel design. I think they are beefy in the right areas to allow for clearancing.

I'm still trying to get a picture of the setup.

[Superman]

The 944 calipers that we use have to be machined and modified such as this to be adapted to the early 911 cars. I've seen them modified like you want but for the 911 application. Talk with some early 911 owners and you should get more detailed info.

[bugsoup]

Thanks for the input, James. So far, all I've gotten from the P-crowd is that I should put 964 or 951 brakes on my Beetle. They don't seem to get the fact that I have already decided to go through the trouble of putting "their" brakes on my car, now they want me to take the easy way out. I don't think so. I'm partly doing this modification to show that it can be done. I'm literally, a couple millimeters away from succeeding. Since I'm not getting a great response from our cousins in the Porsche forums, does anyone else have experience modifying calipers?

[bugsoup]

Derek

I quickly scanned over the responses before. I missed what you had said about trimming the rotors. That might be the ticket. Since the rotors are already 13+ inches, I suppose trimming a few mm off wouldn't be a great loss. Has anyone known somebody that tried this? I assume there is some risk of cracking the rotor by machining it this way. If the tool were to catch the inner vanes of the rotor, I bet something would have to give. I am headed to a machinist (jimw on the STF) to see what he has to say.

[Superman]

I have read that it is okay to shim the caliper (put washers at the mounting point) if it's only a few mm.

[bugsoup]

I'm not sure if shimming would help in this case. By shimming, do you mean putting washers between the caliper and spindle on the axial bolts to move the caliper closer to the center of the vehicle (and away from the wheel)? If so, it would take about .25-.5" in that direction. I'm not sure I have that much leeway (sp?) with brand new pads. That would accomplish basically the same thing as spacing out the wheel without the increased track width, so I won't rule it out.

[bugsoup]

What type of material should I be using to make brackets for the calipers? I was thinking of starting from a solid block of aluminum. If this is the right way to go, would 6061 be the alloy of choice?

[Jim Andritsakos]

Hello Scott!

Well, as for the adapters go for 6061 T6 aluminium.
Now regarding the calipers I think the most simple way is to fit some small spacers (6-8mm) between the rotor and the wheel...

Rgds,