Anyone have any issues with the passenger side front brake caliper slowly becoming lethargic and not releasing all the way. Im on my fourth caliper/drum on my Forester over the years...seem to replace it every three years. Just that brake... Since it doesnt release, it drags on the rotor, heats it up and warps it

could be a bent pin or swollen rubber 'damper' causing it to bind.

 

Although extremely rare - there have been cases of hydraulic lines having an internal lining fail such that a 'flap' is created that acts like a check valve.

17 minutes ago, 1 Lucky Texan said:

could be a bent pin or swollen rubber 'damper' causing it to bind.

 

Although extremely rare - there have been cases of hydraulic lines having an internal lining fail such that a 'flap' is created that acts like a check valve.

I second that- I would replace the flexible brake line on that side as I've heard about the lining collapsing. I had 2 calipers do this on my Legacy GT but the 3rd caliper is doing OK since I replaced the line

when replaced are the pins sticking or freely working perfectly?

who is installing them and what kind of pin grease is being used?

If they’re aftermarket calipers and this thing sees winter road chemicals they could be rusting up. 

id install a used set of Subaru calipers from a rust free state with Sil Glide or other high quality pin grease, not generic permatex, etc.

if the caliper absolutely checks golden and is fine - then replace the brake line with one from Subaru.

ive seen other manufacturers lines fail internally like this but not Subarus, that’s rare. I wouldn’t be surprised if the lines were replaced previously and are lower grade aftermarket.

on ones that fail you can tell by waiting until it is problematic, jacking the wheel up - it’s locked/hard to turn.  Very briefly crack the brake line hold down bolt and it release the fluid pressure (which will be on the caliper side) and it is immediately freed up and the wheel now spins fine (ignoring high rust spots or other high spots on the rotor).  Press brake pedal again and repeat - wheel locks, won’t unlock when you let off the pedal, crack line and it frees immediately. That’s how you diagnose it quickly.

or generic grease is being used on the pins - that swells the pin bushing and the caliper hangs.  It can be intermittent at first as the bushing offers resistance and nkt a hard stop yet.  

Agreed on the pins. When you replace the caliper, is it semi-loaded (comes with a bracket)? If you're reusing the bracket/pins, that's probably the problem. I keep a very close eye on my caliper slides on all my vehicles, and periodically clean and regrease them. Having far less issues since I started using Permatex Ceramic high temp brake lube.

Is it a Stick Shift?
If it is, could be the PHV , better known as the Hill Holder not releasing. The Return spring becomes weak or breaks on them over time.

I had my '05 forester have the right front caliper go bad multiple times- the piston actually sticking.

I finally bought a premium part and has been good since.

I would make sure to flush the carp out of the system too.