I went to start my 242 and heard a pop, I pulled out of the drive way, then the engine ran rough and brakes were hard. So I look under the hood and see the end of the brake booster check valve missing, with the rubber valve part still there. I pull back into the drive way, and find the plastic end of the valve, but then the rubber part is gone. I can't find it anywhere, so I glue the plastic end back on, and now everything seems fine. Do I really need to order a new check valve, I can't find one locally at 'zone, oreilly or napa?

As you already experienced, if that check valve comes apart again (e.g., the glue fails because of engine compartment heat), you'll immediately lose all your vacuum in the booster, and when you suddenly have to brake for some idiot driver in front of you, you will have not one iota of brake assistance -- how will you stop fast in that case?

Get a new check valve (and please don't drive behind me until you do).

Good luck.

Yes, you do need to replace that check valve. Your brakes might seem ok but the vacuum boost will not work right. The purpose of that valve is to keep enough vacuum available for the power brakes to work as they should.

When you repaired the broken neck on the valve, you closed off a vacuum leak to the intake manifold which certainly would make the engine run better.

I'd go to a dealer for a new valve. This is a safety issue. If that's not possible, try as salvage yard. A valve out of a Volvo in the yard should still be good. I've never had one go bad.

I agree with Jim Holst that you definitely should replace this valve and not leave it with repair job you did. Definitely a saftey issue here. I had this same part break about a year or so ago. My local Volvo mechanic had a brand new Volvo OEM part which he sold me at cost. Wasn't too bad. If I recall about $15 or so. Please for your saftey do replace this part. It is a real simple 5x minute job.