If your OBS 7.3 has a belt chirp that keeps coming back, a squeal that shows up at idle, or a habit of wearing belts faster than it should, Ford already had a fix for it. TSB 98-23-14 applies to the 1995–1997 F250/F350 and 1995–1998 Econoline models with the 7.3L. The repair involves upgrading the tensioner system to that of the newer Super Duty models, replacing the original single-arm belt tensioner with the later dual-arm design.

Note: This TSB applies to trucks with 8-rib serpentine belt systems only. Some early engines were equipped with 7-rib serpentine systems. Check your belt before proceeding. 

Image Credit: ford-trucks.com

 

 

What the problem is

According to early Ford releases, the original issue was premature belt tensioner wear caused by the massive never-seen-before torque the 7.3 made (paraphrased of course). All kidding aside, that’s pretty much the truth, the stock setup simply wasn’t strong enough, so it wore out prematurely. Easy as that.

Keep in mind that it’s not just the tensioner that took the abuse. Once that belt starts moving around the added vibrations beat up on the other pulleys, and the accessory items, like the alternator. It’s common to have multiple related issues when this upgrade becomes necessary.

 

Why it fixes it

The bulletin specifically calls for swapping the single-arm tensioner to a dual-arm unit, removing the grooved idler from the system, keeping the flat idler, installing a new belt, and updating the belt-routing. The alternator bracket also needs to be modified so the new setup sits correctly.

Altogether, the reason the fix works is pretty straightforward: the dual-arm layout controls the belt better and is less prone to the sloppy, off-axis behavior that the old single-arm setup can develop as it wears. The result is usually less chatter, better belt tracking, and fewer repeat problems with noise or weird belt life.

 

Install tips

The bulletin’s procedure is simple on paper: remove the belt, alternator, old tensioner, grooved idler, flat idler, and alternator bracket. Then modify the bracket by cutting the grooved-idler support boss off flush and trimming the support rib down 12 mm, or 0.5 inch. After that, test-fit the new dual-arm tensioner, make sure it lies flat, and reinstall the bracket, tensioner, flat idler, alternator, and new belt. The old grooved idler gets tossed.

The biggest install tip is to take the bracket trimming seriously. If the new tensioner does not sit flat on the bracket, do not force it and hope the belt sorts it out.

The second big tip is to use the right tensioner. This is where a lot of people lose time. Over the years, many owners have found that some aftermarket dual-pulley tensioners do not work like the Ford/Motorcraft unit. One commonly repeated complaint is that some aftermarket versions only pivot one pulley instead of both, which changes the geometry enough to make the normal F8TZ-8620-FB belt seem too short. Save yourself the headache, use the Motorcraft part.

One more smart move while you are in there: as we hinted on earlier, inspect the rest of the front accessory drive system. A bad tensioner can beat up the belt and accessories, but a rough idler, dragging alternator, worn vacuum pump bearing, or another unhappy pulley can also overload the tensioner and make you think the tensioner was the whole problem. Always check teh related components when diagnosing belt noise and tensioner failure.

Note: A Super Duty alternator bracket can NOT be used in place of modifying the OBS bracket. The brackets are not interchangable. 

You can find the full Ford TSB below:

 

 

Parts needed

Unfortunately many items have been discontinued, we've listed alternates where possible.

• Updated dual-arm tensioner: F8UZ-6B209-CA
• The new truck belt: F8TZ-8620-FB (Ford has discontinued this PN, here's an alternate K081223HD)
• Or the Econoline belt: F8UZ-8620-BA (Ford has discontinued this PN, the truck belt above is the closest alternative)  
• And the new belt-routing decal: F8UZ-8B656-AB (also discontinued, image below).

*You keep the flat idler pulley if it is still good. You do not reuse the old grooved idler pulley.

 

Final thoughts

TSB 98-23-14 is the kind of fix OBS owners still care about because it solves a problem that never stopped being annoying. If your 7.3 chirps, squeals, or seems hard on belts, the dual tensioner conversion is not internet folklore. It is Ford’s own answer for premature wear in the original setup.

Done right, this swap gives you a better-behaved belt drive, less noise, and a lot better odds that you will only do the job once. And on an OBS truck, that kind of upgrade usually beats throwing another cheap part at the same old problem. Just keep in mind that your truck will use newer 1999-2003 Super Duty belts for future maintenance.

Disclaimer: The information provided on this blog is for informational purposes only. We share our knowledge and experience, but we are not liable for any damages, injuries, or losses that may occur as a result of using this information. Situations are rarely cut and dry in the automotive world. Your situation will likely be somewhat different than what we describe here. Use your best judgment and always consult a qualified professional for automotive repairs and modifications. Your safety is your responsibility.