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Auto Racing/Cutting of Brake mounting points: SAFETY

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Question
Asking you in the race world b/c of your fabricating experience.

The Subaru SVX. great little rare sport coupe of the 90's. Problem was it was plagued by small legacy brakes. There are 1 or 2 BBK's available, but they have had limited success, and astronomical costs.

It has been discovered that modern WRX brakes will mount up the rear w/ no modification.

The front WRX calipers also mount, but bring the braking surface outward so that a stock rotor is not large enough in the diameter. No rotor can be found to fit the new required specs.

It has been suggested that the mounting points on the wrx caliper brackets to be cut off, and then reattached after cutting out a short section of the bracket.

My question:

Is it possible to do this w/o compromising the safety of the bracket? Welding? some other method?  failure would result in catastrophe of course, so safety is of course the ultimate concern.

Answer
Hi James:

I'm not familiar with the exact nature of the Subaru front spindle assembly but your answer is a qualified yes.

First:  your welder should be highly experienced, and able to run a neat and very even weld bead.

Second:  The parts to be mated should be ground to provide a deep "V" so the welding will penetrate all the way through the bracket. If possible, they should be welded from BOTH sides, and both sides should have the "V" ground in them beforehand. Your welder should clamp everything firmly in place before starting, and leave it clamped until it has cooled naturally.

Third:  I would suggest that after the weld is cooled completely, it  be re-heated with a torch and annealed to relieve any internal stresses.  Do this with a large 'rosebud' torch tip and heat the entire assembly but concentrating on the welded area, bringing it to a very dull red, then allowing it to cool naturally. NEVER cool welded metals with water, it causes brittleness.

Be sure to measure everything VERY Carefully before, during , and after each phase of the job. It should be alright. and quite safe. However when you start using it, inspect it carefully after every on track session until you're confident it's OK.  The slightest crack should be investigated. Done right , it should last indefinitely.  

Good luck

Dan Liddy
Sarasota, Florida  

Auto Racing

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Dan Liddy

Expertise

Anything concerning race cars, 20 years competition experience, Senior Competition Driver Instructor , car builder, mechanic, welding, fabrication, tuning , engine modifications, set up, suspension design. Specializing in Datsun/Nissan products. Please submit questions about RACE CARS ONLY. No street cars, no video game scenarios Thank you.

Experience

I have been racing for 20 years, I have been the Central Florida SCCA Regional Championship points for 5 years running, and won the championship in my class 2 times. During my first start in the 60's I won many solo awards and the State Championship Drags. I serve as a senior instructor for SCCA, and have taught in Mercedes AMG events at Daytona, and Dodge Viper Days at Sebring International. I have been in the thick of the competition for all of my career. At one time or another I have driven race cars at speeds nearing 195 MPH. It's quite a ride !

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