[T3] Brake Calipers

[Adriel Rowley]

Sorry did not get to this sooner: packing for the move is taking too long.

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> From: jadney at vwtype3.org
> To: type3 at vwtype3.org
> Date: Wed, 10 Aug 2011 17:11:11 -0500
> Subject: Re: [T3] Brake Calipers
>
> On 10 Aug 2011 at 11:31, Adriel Rowley wrote:
>
> > Adney, how much would it cost for a rebuild with caliper cores without
> > the plates?  How much would the plates cost by themselves?  Starting to
> > regret going the big business route and thinking I should not send my
> > cores out.
>
> I am out of the larger late plates and they appear to be NLA. I will
> no longer be able to supply them. I can align the pistons properly
> and I'll look for a more permanent solution, but right now I have
> none. In practice the pistons seem to stay in position even without
> the plates, but I don't have much experience with this.
>
What is the purpose of the step?  So the plates are to keep the pistons 
aligned?

> > Mind showing how you got the loss of 10 percent calculation for 40mm
> > pistons?  I am curious of what affect 38mm, 39mm, 50mm have.
>
> It's based on the area of the pistons, so take the ratio of the
> squares of the diameters, which for 40/42 comes out to .9070 or
> 90.7%, which is not quite 10% less than 100%.
>
So then 50mm give about 20 percent increase, which would upset the 
balance right?  Couriousity killed the cat... ;)

> Note that there's no change in braking between early and late Type 3
> calipers since both use the same 42 mm pistons.
>
But the force is spread out more due to the larger pads, right?  I did 
try the late calipers (going to do an update after this), and they feel a
major improvement over the 40mm pistons.

> > The two calipers look to have the same size pistons.  Why could one not
> > measure with a caliper the diameter?  Not accurate?
>
> Any caliper is fine, you just can't get in there to measure the
> piston until the piston is removed. The face of the piston is smaller
> than the working diameter, so it's pointless to try to measure the
> face, which is all you can see with the caliper assembled.
>
Fine, figure good to ask. ;)

> > Here is what I got back from Rock Auto:
> > > Thanks for your email. I do show that the FRC3079 has one bleeder and
> > > the FRC3080 has two. Here are the images we have from Raybestos:
> > >
> > > FRC3079: http://www.rockauto.com/catalog/moreinfo.php?pk=522216
> > > FRC3080: http://www.rockauto.com/catalog/moreinfo.php?pk=522919
> > >
> > > Did your mechanic assume that both have single bleeders, or did he
> > > actually check the calipers? We also show that Cardone lists the right
> > > side caliper with a single bleeder and the left-hand caliper with
> > > double bleeders.
>
> I have no way of knowing what those photos are of. There may indeed
> be late style calipers with single bleed valves but made for someone
> other than VW. They might have 42 mm pistons or they might be
> something else. They might even be photos of early calipers, since
> it's really hard to tell the difference in a photo of just one. The
> photo may not be of the actual part. I can't be responsible for what
> you buy from other places.
>
The point of it was the statement about the bleeders.  Found it 
interesting and thought to share. ;)

I still have not heard back on the cost of rebuilt with cores.  Figure
should be around $40 considering cores are about that.  If so, can see 
about saving up and getting them done by you, and know they are good:
still doubt I go a good product once I got them... ;/


Thank you,
Adriel