[1 Lucky Texan]

weird

if you were to let the car idle for 10-15 minutes before moving it, would the brakes feel normal?

 

[1 Lucky Texan]

I definitely did not do myself any favors buying pads on sale once, they were horrible.

so called 'economy' pads either won't last, or won't stop the car. There are also some high performance pads that won't grab at cool temps.

 

[1 Lucky Texan]

not saying it isn't the booster, but that would be on/near the bottom of the list of suspects. Vacuum would be highest at idle and even if the check valve were bad, I'd expect idling would both thaw it out/loosen it AND offer plenty of time for any 'lost' vacuum to build.

While the pistons may move freely, there could be an issue with the slide pins not allowing the caliper to move freely.

And it is probably worth trying to bleed the system again, though I might not understand how that would change with time/temperature.

have you checked the brake fluid level? If it somehow were leaking onto the rotor, you may feel decreased braking until it burned off. Same might true for rust or even dew.

I might be tempted to try a bedding in procedure. At least do the '30 medium/hard stops from 30mph with 30 seconds off-brake cooling between each stop' trick. There are more aggressive bed-in procedures but you can search for those.

 

[1 Lucky Texan]

ours 'may' have slightly more travel in the brake pedal than other cars I've driven, but not much. But it is consistent from the first stop to the last.

I wonder what type of tires Forane is running? that can make a difference.

 

[1 Lucky Texan]

Would vacuum be lower when cold?

yes, due to the higher revs/slightly more open throttle/IACV w'ever. vacuum would be reduced.

That's why I wondered if, say, first thing on a cold morning under conditions which you feel the car would exhibit poor initial braking (*breath!*) you instead, allow the car to warm-up for 15 minutes before moving it. The revs should have come back down and the engine should be warm at that point and have had an opportunity to build vacuum.

Then monitor the performance when you pull away. If it fails, the problem is less likely to be the booster because, vacuum should have had plenty of time to build. If braking is normal, the problem is more likely to be the booster.

I dunno, maybe I'm not thinking right about this.

The booster, with a functioning check valve, 'should' hold a vacuum for a significant amount of time. It's designed to provide 1 or2 'boosted' brake applications should the engine die on the road. I suppose you could pull the hose off it in the morning to see if you hear air rush in or not.

 

[1 Lucky Texan]

I am currently away from home with the car and have few tools. So, have not pulled the vacuum line to see if it has vacuum when starting cold..

I guess I wasn't clear but, I was wondering if the car would maintain a vacuum overnight so, pull the hose before starting it and monitor for air rushing in.

I dunno, not sure if a car should hold that vacuum overnight or not. I know I've read about issues like this, but I'm fuzzy on the troubleshooting.

maybe read here; http://www.subaruoutback.org/forums...en-check-valve-brake-booster-vacuum-line.html

Brake booster not working when cold outside? - 1990 to Present Legacy, Impreza, Outback, Forester, Baja, WRX&WrxSTI, SVX - Ultimate Subaru Message Board

 

[1 Lucky Texan]

thanx for getting back to us!