[FORANE]

The *frozen* check valve is fairly well known.

I thought your descriptions had been during periods that were too warm- above freezing.

Definitely affected by cold - the colder it is the worse it is. I do not know however that I can state with certainty it does not occur at temps above 32 degrees. Does this absolutely not occur above 32 degrees?

Does anyone know a part number and source for a replacement check valve? If it is cheap I might be inclined to replace rather than try to clean out any gunk built up in there.

 

[CNY_Dave]

It's just water freezing in the valve, so 32F is the magic number.

I think the dealer just sells the hose with the valve in it.

 

[FORANE]

ok
I removed the brake booster check valve and sprayed WD40 through it. It seemed to function properly as a 1 way valve as I could only blow 1 direction through it. I reinstalled it and there has been no change. Going down driveway at 35 degrees this am, brakes still a little weak.

I removed the check valve after the car had been sitting for 12 hours and there was no vacuum present. So, I figure it is either a leaking booster or more likely a leaking check valve. I do not have a means of applying a vacuum to the booster for testing its integrity. In either case, the check valve is less expensive and easier to change so I would like to try replacing that to see if it makes a difference.

Can you guys confirm part number compatibility for an 01 outback as referenced in this thread:
http://www.subaruoutback.org/forums/66-problems-maintenance/22468-brake-booster-check-valve.html
It would be a 26151AC110 correct?

 

[FORANE]

I think I found the part number for the brake booster check valve alone without the vacuum hose. It is part number 46403-SE0-003. It is an Alder part also used on acura and nissan. Best of all, it is available on ebay for just $5.65.

 

[FORANE]

Solution!
I can confirm JDM Alder part number 46403-SE0-003 is the exact same part as the brake booster check valve on my 2001 Outback LL Bean.

It also has restored my brake booster function.
Upon inspection of the old and new check valves I noticed the new check valve required very little vacuum to get it to open whereas the old check valve required alot of vacuum before opening like the diaphram was rigid. I believe the old diaphram allowed vacuum to dissipate over night and did not allow vacuum to build up when first started due to its stiffness which increased when cold.

Folks, this is a $5 buck and 1 minute fix. If your booster is weak, especially in the morning and in colder temperatures, look for this part on ebay.

 

[1 Lucky Texan]

thanx for getting back to us!