[T3] 412 Brake Caliper Question

[Jim Adney]

Sorry for the late response on this. I've been busy....

On 5 Mar 2016 at 16:47, William J wrote:

>  These OM piston retaining plates you have , are they the ones that have the 
> center area that fits the piston center with the prongs ? I can't recall 
> what my pistons look like on the pad side . The ones on this car are not 
> like that. They are just flat thin held by the 2 pad pins and have the angle 
> for the piston and no center hole that fits the piston.

There are lots of different styles of plates used by different makes, 
so they often get put on our cars by mistake. The OE ones for Type 3s 
are basically triangular and are held by just 1 pad retaining pin. 
These clip into a recess in the face of the piston and hold the 
cutout in that face at a particular angle.

There are plain rectangular ones that sometimes come with replacement 
pads. These are more of a heat shield than anything else, but they 
can be useful, because you can put a thin layer of the putty that's 
sold to eliminate brake squeal BETWEEN THE PAD AND THAT PLATE.

Never put any kind of adhesive where it can touch the piston or the 
boot around the piston. That will stick to the boot and tear it as 
the pad wears and the piston moves out.  

Some makes use a rectangular plate that is held by both pins and has 
cutouts for the piston face cutout, so these serve as both heat 
shields and piston orientation control.

There are yet other kinds which press onto the face of the piston to 
act as more or less circular heat shields.

The style that is used seems to be mostly a matter of what style the 
automaker prefers.

>  What I really need are the 4 runner boots and 4 of those retaining plates 
> unless they are like mine then 1 will do. 

I have plain rectangular heat shields which I can sell. The OE 
triangular OE style, however, are quite hard to come by, often 
missing, and in short supply, so I prefer to hold on to those for the 
calipers that I rebuild.

I have new and good used air runner boots available. Those generally 
last forever unless they're abused.

> I know my oil cooler seals must be leaking a bit being over 20 years
> old. Just so I have them in case . I have no idea what the cooler fins
> look like since I saw them last in 97 and it still has the original
> rubber seal , looked fine in 97. 

Your oil cooler seals are probably newer than most of ours, so I 
doubt if they are leaking. Once they leak, it will be obvious, 
because even a small leak will wash the top of the case clean, in 
that area. The seals used '70-3 are the same as Beetles from '70-on, 
so those are readily available almost anywhere. I have the earlier 
ones, which are unique to Type 3s.

> The brakes are my next job , I can't recall the last time I changed
> the fluid 2001 maybe. Well past the 2 year required time frame. I'm a
> bit concerned about that yet it's been as long before without any
> problems. 

Yes, flush the fluid, as it's hydroscopic. Even in arid climates it 
soaks up water and becomes corrosive. This is the cause of the vast 
majority of brake hydraulic problems. I use and recommend DoT-5 
Silicone Brake Fluid to avoid this. I have a writeup on its benefits 
and installation. Email me for a copy if you're interested.

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Jim Adney, jadney at vwtype3.org
Madison, Wisconsin, USA
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