welding on 944T caliper question
 

I am going to have to weld the mounting holes to convert the rear calipers from the 944t calipers to my 76'.

Won't the heat that is put into the calipers ruin the seal's? or will they stand the heat from welding?

should I put plug's and weld them in or should I fill them w/weld?

I am doing the same set up that Bill V. has on the rear of his car.

Thanks
OScar

What's the caliper made of?

I'm pretty sure it's aluminum.

why mess with it? rebuild the caliper after the weld and not worry about the seal integrity.

Check out the bottom video http://www.alumaloy.net/

But, can it be done w/o damging the seals? and, how.

Seals will probably be fine but I'd go along with k911sc's advice.

Think about how hot the calipers gets during use and the fact its aluminum. It will disapate the heat very fast.

But, it would never hurt to replace the seals while you have the caliper out, they will be like new.

so its unanimous, rebuilt and we all sleep better...

why not disassemble prior to welding. then you can blast them and make them clean and pretty for the TIG events.

finish off with a nice powder coat or high temp paint.

I agree, the seals fail ina non linear manner starting at a relatively low temp, The Brembo spec on the inner pressure seals is 360F max.

The filler should be an aluminum alloy that retains its strength when hot and should be a light interference fit as it becomes a structural member. Tig weld both sides

My experience welding aluminum is that you'll ruin the seals for sure. Aluminum make dissapate heat faster than other metals but it also conducts it faster and requirement more heat to weld than steel. Also filling holes on aluminum can be difficult, I'd recommend a filler piece with chamfered edges. Don't forget cleanliness is the key to good aluminum welds so use a SS brush to clean the metal real good. Have you heard of the penny trick for the tungsten?

I dunno if these are already made(band around a circle of expandable masses), but a circular steel plug put in the piston hole, while welding, could keep the shape of the bore and lessen the need for a total rebuild.

Sorry, more info would be good. You have an early 911(?) with steel(M) or aluminum(L?) 3" caliper-mounting spacing(?), and the non-magnetic 944 calipers to put on are 3 1/5" or more (?).

The quality of the weld and material will contribute to the ability to maintain stability, control vibration, and heat for track-only racing.
Brakes are no joke. Search for a viper video .mpg here who should have slowed and turned about 90+mph ago.

Word:D If that means "what he said"

Ok, I'll have to rebuild them. Bill, are you saying to use a aluminum plug?, chamfer it and fill the chamfer? Or should I just fill the holes? Which is better?
I have two guys at the shop that weld aluminum very well so the welding will be simple either way.

Thanks
Oscar

Oscar,
FWIW, I'd recommend fabricating a chamfered plug, then size it for an interference fit and install it flush. You'll require less filler material and the caliper will be exposed to less welding heat as a result.

I might try something like using an aquarium pump or windshield washer pump to circulate water through the caliper during the weld. Remove the cross-over tube (you have one yes?) for more coolant volume. Hope this technique doesn't turn the caliper into a steam powered rocket.:)

Sherwood
http://members.rennlist.org/911pcars

No, and a 'google search' didn't come up with a penny trick either. So what's the trick?