[T3] 412 Brake Caliper Question

[William J]

I don't know much about disc flex. I do know for some odd reason the 
mechanism in the late or 73 caliper appears to not allow the pads to hit the 
rotor when the pads are worn down to a point so the metal of the pad does 
not contact the rotor.

 I only know this because one day when braking my car pulled to the left and 
when I looked at the pads one had about 1/16" of pad left. It would not 
allow the right front to break . Now whether this is part of the design I 
can't say for certain, I do recall someone at a local independant VW place I 
used to get parts from told me this.

William
----- Original Message ----- 
From: "Jim Adney" <jadney at VWType3.org>
To: <type3 at vwtype3.org>
Sent: Friday, March 04, 2016 6:07 AM
Subject: Re: [T3] 412 Brake Caliper Question


> On 4 Mar 2016 at 11:25, Dave Hall wrote:
>
>> I don't know the answer, but here's a theory for no mechanism:-
>> The Type 3 Haynes manual says the compensating system was needed because 
>> the
>> front axle design could produce disc flexing, pushing the piston back and
>> increasing the gap between piston and disc, leading to a delay in braking
>> while the extra gap was closed up.  The Type 4 had a quite different 
>> front
>> axle and suspension arrangement, as well as thicker discs that may well 
>> not
>> show the same problem, which meant no compensation system was needed.  I
>> don't know what the 914 front axle was like though.
>
> That's certainly the purpose of the mechanism, but the part that
> might flex is the axle stub on the steering knuckle. Once VW made
> that 2 mm larger in diameter in mid-68 I don't think there was much
> need for the compensation. Nevertheless, I like to see it there if
> the car came with it.
>
> I've always wondered why our late calipers came with it, since that
> was after the axles were strengthened, but maybe the answer is in the
> fact that a few Type 4s were made in early '68 with the smaller dia
> axles, so VW kept the mechanism in place so all correct calipers
> would be suitable for all cars. Frankly, I'm surprised they didn't
> just assign a new part number for late Type 3s and install a cheaper
> caliper on those cars.
>
> But by the time they got around to the late Type 4 caliper upgrade in
> late '72, there was no reason to keep that mechanism, because this
> caliper would not fit on any older cars with smaller axles.
>
>
> -- 
> *******************************
> Jim Adney, jadney at vwtype3.org
> Madison, Wisconsin, USA
> *******************************
>
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