A couple months ago Dave smelled burnt rubber coming from the engine compartment. Upon examination, he found the bolt that holds the alternator tensioning arm to the water pump had broken clean off and fallen into the bilge.
The lack of tension caused the alternator belt to slip and burn. He remembered that it felt weird the last time he tightened that bolt - he was kind of worried that it might have been wanting to shear off. This picture is of an engine similar to ours. Though infinitely more accessible. And way cleaner. Ours is deep in a compartment that requires a contortionist to work on it. The red arrow shows the broken bolt.
The first attempt to fix it involved drilling a hole into the bolt, hammering an “Easy-Out” into the hole and attempting to twist the broken bolt out. (For those not familiar with an Easy-Out for removal of broken bolts see this.) Alas the blot was stuck but good. So Dave just left the Easy-Out sticking out of the bolt and let it support the alternator tensioning arm. Later, he added to the jury rig by pulling the tensioning arm into place with a ratcheting strap.
Dave decided it was time to fix it right. This involved removing the water pump on the front of the engine and the various 20-year old hoses. The worry all along was that one bolt has broken so which of the other 5 bolts will break, too. He solicited help from a friend and started work first thing Saturday morning. It turned out that the bolts all cooperated and the pump was extracted with no further incident. Even the hoses came off without much effort. Hmmm, weird.
A very confusing scene unfolded. Dave and Kirk expected to see the stud of the bolt sticking out of the block. The bolt head sheared off at water pump so there must have been at least the thickness of the water pump body sticking out of the block once the pump was removed. But that was not so - the bolt was sheared clean off at the engine block. So where is the rest of the bolt??? Well - it was still stuck in the water pump body. Huh, how can it break in two places?
So, here is what must have happened over the years:
- Years ago, somebody broke the bolt off in the block when working on the alternator tensioning arm.
- Instead of fixing it correctly (remove pump, extract bolt), they threaded the water pump body to accept a new, shorter bolt to hold the tensioning arm. (Dave always wondered why that bolt was a different size than the others.)
- The new bolt broke (probably because it bottomed out) recently.
There are two bolts involved: An old bolt was broken and left in the engine block; A new bolt is broken off in the water pump.
The new broken bolt that was stuck in the water pump was fairly easy to remove once Dave had the water pump on the bench. However, the old bolt broken in the engine was going to be a bear to drill out accurately. Kirk and Dave went to the work’s shop and fabricated a jig to precisely guide the drilling operation.
It worked fabulously.
Unfortunately, Dave got the bright idea to try to remove the bolt with another Easy-Out. Bad idea. The Easy-Out broke clean off in the bolt. Now, there is a super hard Easy-Out busted in the stuck bolt that is near impossible to drill out. Easy-Outs should be outlawed.
An Easy-Out is made of super hardened steel that is impossible to drill with normal drill bits. After watching various YouTubes Saturday night, Dave went back to the boat Sunday with $50 worth of various recommended expensive drill bits and Dremel grinding stones. After wiping out every tool and going back for more, the bolt was finally drilled out.
A painless tapping job gave the engine block its threaded hole back!
And voila! A nice new hole that fits the proper sized bolt perfectly!
Dave managed to reinstall the water pump and various hoses but was tuckered out after working on it for two solid days. There still is a couple hours of installation and clean up left for after work this week. Ok, cleanup alone might take a couple of hours!