What does that small cannister do, that sits in the rubber vacuum line from the brake booster to the engine manifold?

My mechanic removed it, saying I didnt need it.. But I still have it.. Should I put it back on?

 

Pretty sure its a check valve. So vacuum wont go back out of the booster. If your engine keeps good vacuum when its running, then no you dont need it, but I dont see why he would take it off, unless its broken.

 

Sorry to say your mechanic is an idiot. That is a backflow valve to prevent loss of vacuuum in the booster at low rpm vacuum flutuation. You do need this so you will not have to stand on your bake pedal when engine vacuum drops with random throttle positions. Your brake pedal will get a balled up hard feel to it sometimes without this valve.

 

Thanks guys for the input.. ..I have recently installed a XE268 cam, brakes feel the same at idle etc.. but this canister is going back on first thing in the morning

Thanks again guys.

 

most likely i'm wrong, but i believe it's a filter and the check valve is the barbed fitting the goes into the booster.

 

it is a filter so the crankcase fumes don't get into the booster and deteriorate the diaphram.

 

I wasn't aware there was a filter inside it but I do know it's a check valve. If the engine dies while driving, the check valve will hold vacuum in the booster for a couple of power assist brake applications. Once the vacuum is gone, braking becomes very difficult.

 

It should be a filter, the check valve should be the little plastc piece on the booster.

 

Oops. I stand corrected. The check valve is the piece that goes into the booster.

It's still a good idea to use the filter.