I tool my 300SD for inspection and one of the things I was told is that the calipers are dragging. I'm a mechanical newbie, but figure things out pretty quick (just converted the car to WVO myself). What does dragging calipers mean and what do I do? I did a search, but none of them really addressed the dumbass like myself...

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1980 300D (Luna)
1980 300SD (Sunny)

you press the brake pedal while driving, and when you take your foot off the pedal, the brake calipers are still applying force to the rotor....

Just finished a dragging brake caliper experience with my 911...

Like John said > a dragging caliper means that the brake is always "on"... the caliper fails to retract back into the cylinder > so the brake pad is in contact with the rotor..

Waht to do ??
1. Buy new calipers [co$$$tly] [$300]
2. Buy rebuilt calipers [less co$$tly] [$100]
3. Rebuild the caliper yourself >> actually doable..[$16]

I rebuilt my calipers > was less difficult than I expected , and saved a ton of money..

check out http://www.pelicanparts.com/techarticles/911_caliper_rebuild/911_caliper_rebuild.htm


although the article is for Porsche brake caliper > they all use the same basic principles...

The rebuild is basicilly cleaning up the inside > piston and cylinder, installing a new seal ...

good to flush your brake system every two years > keeps htings "fresh" on hte inside

kgl

First suspect is swollen flex hoses.
An easy test is to jack each wheel and see which one is sticking by turning the wheel by hand after applying and releasing the foot brake. You then open the bleeder. If the wheel then frees up, you have restricted brake hose, not stuck caliper.

My buddy's 85 300 Turbodiesel had that problem too. It had the orginal rotors on it, car has 125k miles. The front rotors were beyond shot. I replaced both front rotors and installed new pads all the way around. I used OEM pads made by Pagid. Bled system and no more problem.

If yours are hanging up enough for the rotors to glow red you have more of a problem than his car had.

This could well be the problem. It seems some of the older hoses would come apart on the inside and act as check valves. Certainly worth a look before replacing/rebuilding calipers and hooking them back up to the same hose.

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Norm in NJ
Next oil change at 230,000miles

For sure .. First check on older systems is always hoses, if for no other reason than it takes 20 secs to diagnose..
I have replaced many after the owners have rebuilt their calipers to no avail...

Ahhhh,
Swollen, tired brake line hoses causing caliper drag. What an astute deduction. I think that my qaud piston calipers are not retracting as they should, not enough to cause overheat though - but enough for concern. The system is as clean as a whistle and has been serviced properly at specified intervals - pads wearing evenly - no pull - etc.. So, at 135K, it is likely that I'm due for new hoses.

Thanks for sharing another valueable piece of information Arthur.