FRONT BRAKE CALIPERS ON A 1976 308

My car was pulling to the right upon even modest braking. In taking the calipers apart, I saw something that I've not seen in previous brake rebuilds. All 4 pistons have an area that encompasses 3/4 of the circumference and sits proud to the remaining 1/4. Thus giving an uneven, or seemingly uneven, application to its pad. I've enclosed a couple of pictures to explain the situation in less than 1000 words. Apparently, this is correct since it was on both sides and, my 308 shop manual seems to indicate this in its diagram of the brake system. I can't think of any reasonable explanation for this, but there surely must be one. Can anyone provide it? Thanks, Steve.
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I can guess that it is to shift the center of pressure towards the trailing side of the pad (relative to the disc motion) and a little towards to OD to get more even pad wear (and not overwear the leading side of the pad):
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Or could be for noise/vibration -- just a thought...

 

thanx Steve, steve

 

Correct. Its an anti squeel method. In some cases it due to design of pad backing plate.
The pictured tool isnt needed. The end of the raised portion ends at 6 oclock when 6 oclock is defined as the axis of the wheel.

 

Brian, Thanx again. stevve

 

For another car a sheet metal plate is used to keep the piston position:
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It fits in the front of 308, but i do not use it. Pic was a test only:
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Sort of pointless I think. Those tabs will not position an improperly installed piston and once installed the pistons do not rotate on their own.

 

If you "improperly installed piston" you cant put it in parallel position. So you see your mistake, but it will not correct it.
"do not rotate on their own" -> the reason i do not install it.

 

What method did you use to get the pistons out. I just split mine today. My 79 has the same type of pistons as yours.

 

Use compressed air through the fluid channel AND COVER THE STUCK PISTON WITH A TOWEL, because once it is free, it can fly out at tremendous speed...very dangerous at that moment. Once I got mine completely disassembled, and cleaned, I decided it was a bigger effort than I should have put out. So, I cut my losses and sent them to PMB Performance in Utah. They'll be done right, finished correctly and I can use the time for something else I want to do. i did all four calipers on two Daytonas, so I have nothing to prove. Remember that the "through" bolts are NOT Torx head, but Ribe style....didn't want to deal with that either. steve

 

I use a piece of wood. Here few years ago on a 308 of a friend:
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And then air...or

I connect the caliper for one Minute again to the brake line and use the brake pedal.

or if a piston totaly stuck:

I do not remove the caliper. Only the brake pads (not easy in this case). And then a small piece of wood or sheet metal between the pistons an the rotor.

So i do not split the caliper if not neccessary. I split only the rear ones.