We had a discussion about this today... didn't really come to any agreement.

Thoughts?

No point to setting venting clearance (0.004") until everything else is completed.

It should not matter.
The piston is physically held there by the adjustment.
Fluid or not, it will still sit in the same place based upon the screw.

Rich

Rule of thumb is to set the clearance after you do the bleeding and then set it to 1/2 of the factory spec or your pedal will have a bit long travel.

but you will have increased sensitivity to rotor warping- which
i think will always happen eventually.

Edit- of course, I do...

Gentlemen ,

What are you talking about ? Rear venting ?

How close your a$$ is to the seat when you roll a cheek to phart!

Please disconnect the handbrake cables when adjusting the rear calipers. Added tension from these can sometimes mess things up.

There is an adjuster on the rear brake calipers to set the gap between the pad and the rotor...

That must be an aspect of the 914 factory brakes. My Carrera brakes aren't equipped with an adjustment . The was in the word venting.

I did some reading on the subject and I'm glad I did, it seems my rear calipers are installed (by Me) incorrectly on two points. I didn't shim them and they are upside down.

What spec do you use for that, Slits?

It doesn't matter when you adjust them. What counts is the rotor is held flat against the hub and that the adjustment is made to .004". I do the outer, then the inner, then I recheck them both. The E-brake cables should be exerting NO force on the lever, other than taking up the slack in the lever itself. I've yet to see significant warpage in a rear rotor, but there's always a little runout. That's why you turn the rotor at least 360 degrees while checking the gap. It's marginally easier to bleed the brakes after the venting clearance has been set.

The Cap'n

My exact measurement is 0.125" ..... relieves the pressure on the cushion

I realize you may consider this setting loose, but it is absolutely necessary to get the appropriate audio from the flapping.

I have squareweave in my '76 and basketweave in my '73 - does 0.125" work for both?

Basketweave diffuses the sound

Actually the basketweave enhances the sound while diffusing the smell.

Rich

Semi-serious question, I've always figured if I set the clearance too low it will work
itself out, by wearing the pads a little, and if I set it too high, itr will work itself
out as the mechanism adjusts.

So aren't we really setting the clearance only for about the few days/weeks/months
until this happens?

i don't think so...
I believe the clearance will track with the pad wear.

Nope. At least, that is not my understanding as to how it works.

The 914 rears do not self adjust at all, so you need to re-adjust them every 6 months or at the start of every driving season. As the pads wear, the calipers have to push them farther to get to the rotor, until they just don't work at all.

Zach

If they are not meant to adjust, please explain the purpose of all the parts
inside other than the screw and locknut and why they are not directly connected
to the piston.

Read this, and find out.

Eric's Rear Brake Venting Post

The above thread should be in Classics, BTW.

Zach

Okay, first of all, right in that thread, The Cap'n specifically states he's never
had to re-set the venting clearance between pad changes.

Second of all, if they were not designed to be self-adjusting, is there a spot in
the Owner's Manual that says to adjust rear venting clearance as part of
periodic maintenance and not just when putting in new pads?

Not that I'm saying they all work, or the design works well, but I believe that
every time the brakes are applied there is small force that is supposed to
make the mechanism move outward by rotating on the screw. But it's been
many years since I've had the parts out.

That's NOT true. They self adjust as the pads wear. You DO NOT have to periodically readjust them.

The Cap'n