by Chris Miles
If you’ve ever had to replace the alternator / water pump belt (or just adjust it,) you know what a pain it is – especially if you’re broken down on the side of the road! So, to make it easier, I have been using a turnbuckle style alternator tensioner. It’s made from parts sourced from McMaster Carr. You don’t need to install this now, but it’s a good idea to have it in your car, so that you can install it the next time you replace the belt. (You SHOULD have a spare belt in the car too – Gates #7495 – www.rockauto.com/en/moreinfo.php?pk=3913&jsn=10393)
You’ll be replacing the existing alternator tensioner bracket (DMCT Part#: 110102) with this new tensioner. Here are the parts you’ll need to build this replacement bracket:
- Stainless Ball Joint Rod End – MC #59915K23 – You’ll need to order a RIGHT hand threaded one *AND* a LEFT hand threaded one. (https://www.mcmaster.com/#59915K23)
- Coupler Rod – MC #8419K12 (https://www.mcmaster.com/#8419K12)
- Jam Nuts – McMaster doesn’t sell nuts individually, so you may be better off to source them locally.
The coupler accepts a ½ inch open-end wrench. Simply rotate the coupler to extend the tensioner, which pushes the alternator away from the water pump pulley, thus tightening the belt.
I’ve been using these on both of my DeLoreans for years, and have never had an adjustment problem.
At the time of this writing, the rod ends were about $14 each, and the coupler nut was $18. The jam nuts are probably less than $1 each. For about $50, you can have piece of mind that you can replace your broken or damaged alternator belt on the side of the road quickly and easily.