87 325 brake drag/bind/overheat

[Tony Canike <canike@xxxxxxxxx>]

Well, after 14 years of flawless operation of the entire brake system, the 
drivers front caliper is binding (smoking hot on highway binding.)  Guess 
all those brake fluid changes paid off, but you can't stop time...   I did 
replace rotors and pads about 2 months ago.   There were sounds of very 
light dragging (occasional squeaks) starting about 2 weeks ago.

Anyway, what's the best way to tell the exact cause of the problem?   I'm 
guessing that the piston could bind, the guide pins could bind, or perhaps 
there is a hydraulic/hose/mastercylinder problem.

When I pull the wheel, apply brakes, release brakes, and try to turn the 
rotor there is significant drag - need tools to turn it.  I opened the 
caliper, pulled the pads, brushed out stuff.  The piston returns with what 
seems to be normal resistance (medium pressure on water pump pliers pushes 
it back).  Guide pins are well lubed and move easily, perhaps with a little 
slop.  Put it all back together, and it still binds after applying 
brakes.   Now I find that a rap with a mallet will unbind the caliper - 
doesn't seem to matter where I whack it - a good whack frees it up.

Ok, so I'm over thinking this and should just replace the caliper.  But 
it's Sunday morning, and Sunday mornings are for farting around anyway....

Do the guide pins wear?  (228K miles, 14 years, guess everything wears...)

Do I replace calipers on both sides while I'm at it?

Do I replace the rubber brake lines (original) ?

Thanks,

Tony.

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