EagleTribune.com, North Andover, MA

August 26, 2012

Mysterious squeak can be difficult to trace

Under the Hood
Brad Bergholdt

---- — I have a 1995 Saturn SL-2 and tow it behind my motor home. When my air scoop in front started to drag on my driveway, I had my front shocks and coil springs replaced. After I took it out of the shop, there was a loud squeak when I would turn the wheel right or left. I informed the service manager, who is also the owner, and he said that it would go away after I drove it a while.

A few days later, I took it to another shop, and they said that it had a bad right shock. The manager of the original shop said that he could not fix it, so if the other shop could, to go ahead and he would reimburse me the cost. I did, but replacing the shock did not eliminate the squeak. The second shop replaced the tie rod ends, and it still did not fix the squeak.

I am afraid that if they have to replace more parts that it will cost me more money. Do you have any ideas as to how to stop the squeak?

This is an odd situation for two reasons: It seems really clear the squeak wasn’t there until the struts and springs were renewed, and why did the first shop take such a hands-off approach to resolving it?

Your Saturn, like many small and midsize cars, employs MacPherson struts in the front suspension. Struts combine the shock absorber with the upper pivoting part of the suspension, creating a compact and lightweight suspension system that’s well suited for transversely mounted powertrains. A strut consists of the shock absorber tube, the coil spring and a strut mount at the top. The strut mount serves as a bearing, allowing the strut to rotate as the wheels are turned, and as a cushion, to dampen harshness. The strut mount attaches to the upper inner fender of the vehicle body, and the lower end of the strut bolts to the steering knuckle.

It sounds like either one of the replacement coil springs isn’t seating properly in its nest at the bottom of the strut or the upper spring seat, a rubber disc, is out of position. Another possibility is the bearing within the upper strut mount lacks lubrication or is failing.

A squeak such as this can be challenging to pin down, as the front wheels likely need to be on the ground for the noise to occur, loading the strut components, which are difficult to access. Also, the squeak seems to radiate from all directions.

The best bet for tracking down the exact source is to very carefully touch with fingers, or use a stethoscope to listen at various component locations for a tearing/grating vibration as a helper turns the steering wheel back and forth. The vibration will be much more localized than the squeaking sound. Another method is to duplicate the squeak, then shoot a narrow stream of WD-40 at selected locations, starting at the bottom and listening for a temporary change in the offending sound.

I’m baffled why the first

shop would take the approach it did. Who better to fix this than the person familiar with the work originally performed? It’s possible this isn’t a workmanship error or defective part, but simply bad luck that the replacement spring’s lower coil diameter isn’t a perfect fit for the strut nest.

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Brad Bergholdt is an automotive technology instructor at Evergreen Valley College in San Jose, Calif. Readers may send him email at under-the-hood@earthlink.net; he cannot make personal replies.