My 2000 Protege brake booster hose split (it dried out) where it connects to the intake manifold which caused my Protege to idle really rough and try to shut off at idle. I found the hose, but it was $30.00 almost everywhere I looked. I went to the auto parts store and got one foot of standard fuel line 7/16" which is almost an identical inside and outside diameter as the OEM hose ($1.49). Even though it is the same thickness as the OEM hose, it will slightly collapse due to the vacuum. The OEM hose has a hard plastic tube inside to prevent collapse. I went to Lowes and got 1 foot of the opaque (kind of white but not quite) stiff 3/8" polyethelyne tube for .22 cents. Take the hose to the big box home improvement store to make sure you get the right size poly tubing. The poly tube should fit rather easily into the inside of the fuel hose. DO NOT USE THE CLEAR STUFF, IT IS TOO SOFT. The poly will slide snug inside the fuel hose but will slide all the way if you straighten the fuel hose. NOTE: There is a valve inside the OEM hose that holds vacuum to the brake booster when you shut off the engine (in case you are driving and the engine shuts off you will still have power brakes). You must locate (by looking at the OEM hose and feeling it) the valve which is about 1/3 of the way from where the OEM hose connects to the brake booster. Without cutting off your fingers, take a box cutter type heavy duty knife (or whatever might work for you) and gently cut the hose just behind the valve so you can see the end of the valve. If you damage the valve, it is over. The valve is located INSIDE the OEM hose and is a white plastic thing about 3/4" long and looks just like a .45 bullet with openings in both ends. One end is flat, the other is rounded. CAREFULLY cut the hose as to not damage the valve until you can pull/push the valve out of the hose (I used a wooden dowell). THIS IS IMPORTANT - The rounded end will go in the hose towards the intake manifold fitting- it is a ONE WAY valve. Measure the fuel hose to the proper length not cutting it too short. I used 11.25" and routed the new booster hose OVER the two smaller hoses. Fits fine. Since the hose will not curve and twist etc as the molded hose does, it will be slightly longer than the OEM hose. Now cut the poly tube to the same length MINUS 2 inches (this allows you to push the hose on each connecter and tighten the hose). Measure about 3" from the end of the poly hose, and cut the poly hose in half (this allows you to place the valve between the two pieces of poly which will be inside the fuel hose. Push the longer poly hose through the fuel hose stopping about 1" from the end. Now rub a small amount of liquid detergent on the outside of the valve and insert the valve into the end of the fuel hose opposite the end where you stopped with the poly that you just inserted. Now use the smaller piece of poly hose to gently push the valve into the hose until the valve hits the end of the poly already inside the hose. It is easiest if you hold the fuel hose straight. NOW MARK THE END OF THE HOSE with the short poly inside (I used masking tape) so you will know which end connects to the brake booster. You should have fuel hose only on both sides for about 1" or so (not critical, it can be 1.5").
TO TEST THE VACUUM VALVE and make sure it is installed correctly: blow into the end of the fuel hose that is marked for the booster and the air should NOT go through the valve. Blow into the end that will be attached to the intake manifold and you should be able to blow through it. If you screw up and don't have power brakes, just reverse the hose connections, you don't have to mess with the hose you built. Use the original hose clamps or get new ones, the old squeeze clamp OEM style ones will fit fine if you can deal with those.
This worked perfect for me. I have been having rough and smooth idle for about a year now and could not find the cause. Apparently the old vacuum booster hose had a tiny split that would open and close at times and it finally became a big split. My power brakes are now REALLY power brakes and the car idles so smooth you need the tach to make sure the engine is running. I can use the $28.00+ savings to buy gasoline to drive my Protege for about a month. I was not going to pay $30.00 plus for something I could make that is identical to the OEM part.

 

niiiice!!!!

 

Oops. I replaced my brake booster hose with a regular fuel line hose. I didn't realize it had a check valve. No wonder the brake pedal gets hard to push when I turn the key off.