97 Passat diesel check valve exploding...

I have a 97 Passat TDI Diesel, and the check valve that goes from the booster to the engine thing explodes. This of course, causes the brakes to be really hard to press.This has happened 3 times in the last 4 months. what's the real problem? I'm not sure if a diesel engine can backfire and cause this........and I'm also wondering if I can cut the tube, rig it so I can install an aftermarket $3 check valve from autozone (cheaper than paying 75 bucks for the whole thing), and will this have any negative effect......any help would be appreciated to help this stranded college student....