Auto Service World
Feature   August 1, 2011   by Tom Venetis, Editor SSGM Magazine

How To Prevent A Comeback

Avoidable mistakes can make for happier car owners, happier technicians

There is an expression in this industry that all shop owners and technicians know and dread – the job done a second time is one done for free. This happens when the original problem that is fixed persists and the driver of the vehicle comes into the shop seething.
This can happen even on the simplest of jobs, such as a belt replacement. How many times has a timing or serpentine belt been replaced, only to have the diver return complaining that the squealing noise, which made them drive to the shop in the first place, is still happening after supposedly being fixed? Thankfully, this scenario does not happen too often; but still often enough that it should leave technicians wondering why it does happen in the first place.
SSGM Magazine decided to ask some manufacturers of today’s newest belt and tensioner technologies why such problems happen and what can be done to avoid them. The goal is not so much to sell more of the technology, which will happen regardless as vehicles age and parts need to be replaced, but to help technicians improve the customer’s experience with the shop and its staff, thereby generating profit as customer’s return for future work.
So what causes a comeback with a simple belt replacement job?
According to Bill Hay, vice-president of sales with Dayco Canada Corp., it is sometimes as simple as “not knowing what to look for when it comes to the belt part of the job.”
“If (a technician) has an issue with the belt drive system, be it a noise, a chirp or a squeal, the technician automatically goes to the tensioner, thinking it has to be a tension issue,” Hay adds. “The problem comes about because instead of diagnosing what the trouble is, they say it has to be the tensioner and then replace that part. What the technician may not have realized is that the belt has become badly worn. So replacing the tensioner does not fix the problem.”
This usually happens because today’s new belts have moved away from the older neoprene technology to EDPM or Ethylene Propylene Diene M-class rubber. EDPM produces wear patterns that are markedly different than those in neopren belts. It is something that has to be explained to vehicle owners. Belts made with neoprene have distinctive sets of visually discernable wear patterns, such as chunking or cracking, when the belt achieves some 50-60,000 miles of use. When this happens, it is time to replace the belt. EDPM, however, wears more like a car tire, slowly losing material without cracking or chunking. One has to use a special tool to measure how much belt material has been lost.
Dayco Canada and Gates Canada offer easy-to-use wear gauges that allow a technician to check for that wear. They are also nifty for showing vehicles owners that an EDPM belt is worn as on visual inspection a worn EDPM belt looks the same as a new one. It should help prevent a vehicle owner from thinking the shop is trying to sell them an unnecessary repair and part.
Marc Alary, marketing manager with Gates Canada Inc. says along with spending time correctly diagnosing where a problem is, it is also important to treat the belt system as a system, a combination of many components that have to work smoothly together.
“It needs to be treated as a system, and replacing an individual component in that system without verifying and considering other system components could lead to customer comebacks,” he adds. This means making sure that when replacing a belt, one takes the time to inspect the pulleys to make sure they are in good working order and are aligned properly, and that the tension has been properly set, even with automatic tensioning systems.
That is why it is recommended that the whole system be replaced rather than individual components. If a technician needs to replace a worn belt or pulley at 80,000 miles because of wear, one can be certain that every part in the system also has worn out as well. A worn pulley may not be causing a problem right at the instant the vehicle is in the bay, but one wants to avoid the possibility of that pulley squealing in a few weeks time after having installed a new belt; and then dealing with the angry customer who comes back wondering why the technician did not replace that defective part when he or she had the chance.
“If a mechanic is going to spend three to four hours working to get to the timing belt in order to change it, it is cheap insurance to change the other components as well,” adds David Hirschhorn, director of brand management with CRP Canada Inc. “You know that if you do so you will not have to go back there for another 80,000 miles.”
One other challenge is to make sure the pulleys are properly aligned. This is critical in today’s newer engines, according to Dayco’s Hay as the pulley systems and belts now have to operate a wider range of systems and alignment is critical.
“The integrity of the belt today is being challenged today by all of the different accessories inside a vehicle,” adds Hay. “In some cases, there can be nine to twelve different pulleys under the hood of a vehicle, taking care of such things as the power steering, the air conditioning, the alternator, for example. So it is very easy for a pulley to get ‘out of whack,’ or misaligned, which is why it is so critical that pulleys be aligned properly.”
Hay says when a misalignment happens, it will eventually force a new belt out of the pulley and cause it to hang either to the left or the right, thereby causing the ribs of the new belt to come into too much contact with the side of the pulley. This will produce that annoying noise that will send a vehicle owner back to the shop. SSGM’s technical editor Jim Anderton has a video which demonstrates Dayco’s Belt Alignment Kit and its tools to ensure proper pulley alignment:
Something else to remember, and one emphasized by everyone spoken too by SSGM. When installing a new belt, use fresh gloves to prevent any errant dirt, grease or lubricants from getting onto the belt; or using a screw driver or crowbar to get the belt onto the pulley, as either will damage the belt and cause premature failure.

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