[v8volvo]

Welcome to the forum, and nice wagon!

Given your description of what your mechanic has proposed, I would look for someone else to do the front belt as well as the rear. Removing the rear belt is a necessary step for correctly changing the front belt. The front belt takes a lot of special tools - more than the rear belt does. If you look through the procedure for changing the front belt, you'll see that what the mechanic is suggesting makes no sense. If he wants to just do the front belt and not the rear, then unfortunately it's clear that he doesn't know how to do either of them. The risks are much higher with the front belt than with the rear belt. Any missteps there and the engine, which you have carefully cared for all these years, stands a large chance of catastrophic damage.

If it's running well and the pump is not leaking, then there's no strong argument for replacing the pump preemptively. As long as it is cared for with timely fuel filter changes and no questionable fuel run through it, the VE pump has an almost indefinite possible life span. It is sensitive to overtensioning of the rear timing belt, which can wear out the input shaft bushing and lead to shaft seal failure, but beyond that, mechanical problems are relatively unusual.

I would try to find a VW/Audi specialist that is accustomed to working on 5cyl 2.0L Audi diesels or VW LT van engines and have them do both of the timing belts, as well as the water pump and idler rollers in front. A Volvo specialist who has direct knowledge of this engine and can show you his set of D24 special tools would be fine also. Based on what you have said, I would avoid getting your current mechanic involved with this job, even if he may have served you well in the past on less particular work.