Help identify a part, please

rriigc · Post by **rriigc** » 12 Jun 2022, 07:37

I recently had a ton of work done to keep my 2004 XC70 alive, including a new fuel pump and replacement of the failed turbo with a salvaged one. Car runs ok, but yesterday when I checked the oil, I noticed a 3" long steel spring sitting loose on holes and a two-piece black plastic part cleanly separated into two parts. I've reconnected the two pieces in the photo, but the plastic clips that hold the pieces together are partially broken.

I'm having trouble identifying the part and could you some help. Is the spring part of this assembly, part of something else I should worry about, or just a cast-off part from the work I had done. Attached photos show the spring and the mystery part (near air filter box with orange connector).

: IMG_2105.JPG (59.88 KiB) Viewed 455 times

I recently saw a loose gas cap text warning and a OBE code P-0442.

: Capture.JPG (122.31 KiB) Viewed 455 times

rriigc · Post by **rriigc** » 12 Jun 2022, 07:39

Meant to say that the spring was sitting loose on some "hoses," not on holes.

Post by **abscate** » 12 Jun 2022, 08:51

The infamous brake booster vacuum valve. It nicely flies apart at about 125-150k and disperses parts into the engine compartment. Get this fixed so your brake vacuum pump isn’t stuck on permanently and burns out.

Topic here

viewtopic.php?t=43817&hilit=Brake+vacuum+switch

rriigc · Post by **rriigc** » 12 Jun 2022, 18:21

Thanks very much for the information. I thought it was vacuum or or pcv, but I never would have guessed brakes.

Is it unusual that I haven’t noticed any degradation in braking, cold engine or otherwise? The thing was (is) clearly in pieces and not functional.

Post by **abscate** » 12 Jun 2022, 18:29

It senses when vacuum is low and turns in the vacuum pump. I think it defaults to turning the pump on in failure.

Post by **BlackBart** » 12 Jun 2022, 20:00

Is this a good preventative maintenance piece to replace now instead of when/if it fails?

Post by **abscate** » 13 Jun 2022, 01:46

BlackBart wrote: ↑12 Jun 2022, 20:00 Is this a good preventative maintenance piece to replace now instead of when/if it fails?

You can put a black zip tie around it to stop it from flying apart or go with the new, improved one which doesn’t detonate.

rriigc · Post by **rriigc** » 13 Jun 2022, 12:13

Is the spring I showed in my photo actually part of the break booster vacuum valve, that scattered when the valve failed/exploded?

Post by **abscate** » 13 Jun 2022, 15:33

Yes, it’s part of the vacuum operated switch