The Portal Hub: All things Pinzgauer, Haflinger, Volvo 303 and more.

The Portal Hub: All things Pinzgauer, Haflinger, Volvo 303 and more.

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 Brake Job 
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Joined: Wed Apr 14, 2004 9:58 pm
Posts: 1392
Location: Idyllwild, CA
Post Re: Brake Job
what is the difference between 2 clicks, a few mm?

I'm just going from memory, but let's try a bit of a thought experiment: if the adjusters have 1mm thread pitch, and if there are 16 points to "click", then 2 points is 1/8th of a rotation; that's 1/8 of a millimeter of (roughly) the circumference of the shoes. Divide that by PI, and two clicks means that the shoes change their diameter by 0.039mm - that is roughly half the thickness of paper, and half of that is on one side of the diameter, the other half is 180 degrees around the drum. The shoes ride VERY close to the drum when properly adjusted.

So two clicks is roughly two hundredths of a millimeter between each shoe and the drum! Even if my guesses were wrong, they won't be too far off so the general notion of a very small distance is still applicable. This is why brake adjustments are needed, it does not take much wear to change the spacing and require that the spacing be put back to what works well.

And there are what the parts list calls "static pressure valves" under the master cylinder that keep the shoes from retracting too far, too fast. So if you need to pump the brakes first thing in the morning, they need adjusting. Once they are "pumped up" they they only retract enough to allow the drum to turn; so braking again in short succession will usually NOT need pumping again. But if they need pumping at any time, adjust them properly.

Jim M.
712W and 710M

Thu Jun 02, 2016 9:11 pm

Joined: Thu Jan 22, 2015 4:00 pm
Posts: 133
Location: San Antonio, TX
Post Re: Brake Job
Jimm391730, always a wealth of information. the tolerances are pretty remarkable, it took a lot of fooling to even see the pads move. Thankfully I documented which direction adjusts the brakes in or out, so don't have to do that again. I will be redoing these adjustments and going 3 back instead of 5. Should be a bit easier now that everything been loosened/anti-seized

Thankfully my brakes have never needed pumping to work but I will watch for it.

Fri Jun 03, 2016 7:07 am
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Joined: Wed Jan 18, 2012 9:07 am
Posts: 230
Location: Vienna, Austria
Post Re: Brake Job
my 5 cents of wisdom:

on the front wheels i first ge one brake shoe to touch the drum, go back five clicks, in order to avoid any influence on the second one.
make the second one touch, rev it back 3 clicks and tighten the first one two clicks.

just had my tech inspection, and passed with identical brake readings ; no more need to hold the steering tight when hitting the pedal..

My Pinz has NEVER been with any army

Fri Jun 03, 2016 2:25 pm
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