Hello All,

This is a PSA to avoid Prothane bushings for installation on 99-06 Sierra/Silverado trucks. Based on the failure I have experienced I would not recommend them on any vehicle until they update their formula and provide extensive testing data showing the issue has been fixed. Suspension parts are critical safety items and a failure like this can cause unpredictable, dangerous handling.

Truck:
2003 GMC Sierra SLT Z71 4WD 5.3 Extended Cab
(If it matters, the truck had new shocks, new brake pads/calipers/discs, new wheel hubs, and new balanced tires installed at the same time these were installed - an alignment was performed by a reputable shop immediately after this work as well. Everything was replaced with OEM ACDelco/GM parts other than tires and these suspension bushings.)

Products:
Product ID: 71168
Product Name: Front Sway Bar Bushings and Endlinks - 36mm (1.42 Inch)
Product ID: 191750
Product Name: Prothane Super Grease - 3 Pack

I installed these bushings two years and almost exactly 10 thousand miles ago. I cleaned the sway bar with rubbing alcohol before applying Super Grease to the bar and bushings. I installed them exactly per provided instructions and Sierra service manual. All bolts were torqued per service manual specs with a recently calibrated torque wrench with <2% variation (friend works in electrical testing and has a regularly calibrated high-end torque wrench).

The bushings fit perfect and tight around the bar, no squeaking or noise, and the handling was great at first. Based on ride quality, I believe these compressed and failed around 5-7 thousand miles after installation, but I cannot confirm that. All I can say for sure is they failed within 10 thousand miles of installation. Both sides failed equally in the same way.

Please see attached picture.

I emailed Prothane with my concerns and received this as a reply:

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"After looking at your pictures, I have no explanation on what happened, I’ve been doing this for over 17 years and I can say I never seen this happen unless it was installed without our Super Grease, which you said you used. All of our products come with a Life Time Warranty, I would be happy to send you another set if you would like, just let me know.

Another reason for something like this is if there was some kind of rough edges on the Bar which could cause it to erode the Bushing, but yours looks pretty clean."
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I will not be using Prothane again and cannot recommend using them for suspension bushings. If you are looking for an alternative, I would recommend sticking with OEM bushings.

If you have installed Prothane bushings, please take your wheels off and inspect them, maybe I got a bad batch, but if this happened to me it's likely some of you may have the same issue.

Stay safe out there,

Regards

 

Where you drive can have a lot to do with how the bushings perform.

What if you tried a different brand?

 

10k miles have been mostly freeway, pavement only, haven't even been on a gravel road.

I already replaced these with OEM ACDelco bushings.