Replacement bolts, help!

Ok so I changed the water pump on my 96 riviera and noticed 4 bolts needing replacement. Outside of the water pump there is a cap that the accessory belt runs around, from looking at the series 1 water pump replacement write up it's the camshaft pulley. There are 4 bolts that secure it to the water pump. Does anybody know what bolts to get? Any help would be appreciated. Thanks.

What's wrong with the bolts that they need replacement? I'll assume that the heads are stripped?
If they do actually need replacement, I would take one of the bolts to a bolt supply place where they can give you exactly what you need. I say a bolt supply place because it's rare that you can go to the auto parts store and find exactly what you need. Usually the bolts in the sleeved packages are too short, too long, have a shoulder on them that you don't need, or can't find the proper grade. I use this place right by me all the time. I always get what I need, and smaller bolts like that aren't more than like $0.45 each.....if that. So, really, you actually get ripped off at the auto parts store 'cause you have to pay for the packaging.

If the heads are stripped, replace them. If the heads are not stripped, and the threads are ok, I would just re-use them.

Sometimes the heads on that style bolt are the wrong size from anyone except the dealership. Most bolts I will get at a good hardware store, but sometimes the dealer is the only way to go. Sometimes, dealerships can be surprisingly inexpensive for something like a specialty bolt.

But if at all possible, just match them up at a hardware store. Bring the pulley with you so you can make sure the heads will work out on the new bolts.

Using either a grade 5 or grade 8 screw will work. The grade 8 costs more, but you will not need the extreme hardness of a grade 8 to attach a water pump. If this were a trailer hitch or some other load-bearing component, I could see the value of using grade 8. However, some see value in using the highest grade, as they don't cost that much more. Technically, grade 8 is more brittle, however the point at which a grade 8 finally breaks is well beyond the limits of grade 5.

Grade 5 screws have 3 marks on the head, grade 8 screws have 6 marks. No marks means grade 1 or 2. DO NOT use less than grade 5 on any part of the car. For suspension components, I always use grade 8 to be safe under the extreme loads. For the engine, grade 5 should be fine unless otherwise specified.

There is the temptation to use stainless steel screws in place of the OEMs, but this is not always a good idea. First, stainless fasteners are typically only half as strong as grade 8 (non-stainless) steel, and maybe less than grade 5. Even though you probably won't need the strength for engine parts, there are other disadvantages to using stainless. Personally, I prefer a grade 5 or 8 screw with a black oxide coating - these will resist rust pretty well, and you know you have the durability to operate safely for the life of the car.

Metric screws use a different system. A class 10.9 metric is similar to a grade 8 in hardness. Class 8.8 metric is similar to grade 5. Class 12.9 metric is a higher strength fastener, comparable to "grade 9" (in theory does not exist), but these are reserved for aircraft use - there is normally no reason to use a screw of this strength on any part of a car.

Good luck.