I was replacing my water pump on my buick 350. I ended up breaking off 4 bolts with all of them flush. So I tried the left drill bolt and extractor and nothing worked. So I decided to weld washers and nuts to the broken bolts and was able to get 2 of them off. As I was checking my work I think I might have warped the timing cover. "I'm a first time welder" Should I just buy a new timing cover so the water pump will just mount to s new cover with new holes? I didn't break none of the long bolts. Only the little 1/4-20 bolts. Let me know. Thanks
If you buy a new cover from TA, buy it with the oil pump already set up, unless you’re comfortable and familiar with setting up a Buick oil pump. If your cover is still on the engine, try working with what you have especially if the oiling system is fine, just concentrate on the water pump bolts. Remember if YOU DO decide to replace the timing cover, there’s the oil pump set up, fuel pump, distributor, front edge of the oil pan gasket to deal with, also removing the crank balancer, and as long as you have the cover off, replace the timing set. It’s a rabbit hole!
If you can successfully drill the broken bolts out, you can helicoil them. I did, but I was able to successfully drill the bolts out straight. I carefully ground them flat, center punched them, then drilled them out with progressively larger bits. Worked like a charm, but your mileage may vary.
After it's cleaned up, install the water pump without a gasket and use a feeler gauge to see if it's warped.
If warped (try the feeler gauge as above), could probably run a long file across & get it pretty close —close enough that "Right Stuff" will seal it. I'd certainly try that before buying a new cover.
This worked for me, and only cost 1$. Used a 5/16 1 inch long roll pin. Remove old pump, if the broken stud in not flush with the mating surface, flush it, being carful not to damage surface. Clean the old gasket from the water pump. Support the under side of the pump on 1x2 blocks so the impeller does not hit, this will form a level surface to in-large the broken stud hole to 5/16". Drill press works the best. Then the roll pin will slide into the 5/16 hole. Bolt the water pump back on the front cover with at least 2 bolts. insert a 3/16 drill bit into the hole in the roll pin, it just fits, and drill out the broken threads. the 1/4-20 tap, need about one larger drill size to tap, but it is easy to in-large the hole, the initial pilot hole is the difficult one, with a steel bolt and alu cover. It worked for me.
