Nissan says worry, Firestone say don't worry re "bearing scoring" - photo attached

I just had brakes redone at Nissan on a 2003 Pathfinder. Nissan said that when the last brake job was done (by Firestone), the bearings were overtightened causing “scoring” from friction. Nissan says there is a chance that this may have weakened the metal from repeated heating and cooling over about 40,000 miles. Nissan said that it’s unlikely, but possible, that a break can cause the wheel to fall off while I’m driving. I took it to Firestone who looked at it (see photos attached) and said it’s just normal wear for a car with 140,000 miles… nothing to worry about. I’m a bit freaked out about notion that a wheel can fall off while I’m driving. Any professional thoughts? Thanks so much!!

Some issues like that in the picture can be due to wear over time. No matter who or what is at fault there are some issues with the metal bearing surfaces shown in the pic.

The odds of a wheel falling off are somewhat slim unless there has been some noise such as rumbling or grinding involved. If noises like that exist then a vehicle should not be driven as loss of a wheel is entirely possible.

Based on the pic, yes bearings are needed.

I think it’s just about impossible to prove Firestone caused it, what about the shop before them?

At 140K miles, you’ve done great in getting your useage out of these bearings. Whether it was caused by firestone or just normal wear and tear, it really doesn’t matter. Pony up and replace it so you have the peace of mind. sometimes when there is a direct correlation and an easy proof/documentation of causality, you ask people to pay for their mistake.

When there really isn’t, you just move on with life.

I’m not familiar with the Pathfinder’s bearings - are these the front axle? Aren’t they conical roller bearings? If so, the axle picture on the left has nothing to do with scored bearings, that’s where the races sit. If Nissan tried to tell you that was scoring, I’m suspicious. As for the right hand picture, without knowing that the race was wiped 100% clean it’s hard to tell.

Is there any unusual noise from either front bearing?

At 12 years old and 140,000 I would look at those bearings and say they are worn and recommend replacement, normal wear and tear.

"The sky is falling!!!

Replace the bearing if there is any concern but like @texases I don’t see any indication of damage to the spindle which I assume is what the Nissan dealership shop is condemming. I wouldn’t expect excessively overtightened tapered roller bearings to last 40,000. Very unlikely. And I’m no fan of Firestone.

“And I’m no fan of Firestone.”

I agree. Normally when Firestone says not to worry…it’s time to worry.

If you do get new bearings, find a good independent shop. The dealer will be 2X more expensive, and I wouldn’t take it to a chain, like Firestone. Replacing front wheel bearings isn’t rocket science.

Replacing front wheel bearings isn't rocket science.

I agree…but I’ve seen several so-called qualified mechanics who don’t the proper way to re-pack wheel bearings.

No doubt, @Mike. I have seen far too many supposedly professional mechanics who fail to fully seat races while some seem to have a great aversion to getting grease on their hands.

Rod Knox I have hand packed a few (quite messy). I remember a tool where the bearing was clamped down and grease pumped in. The new grease forced the old grease out.

Yes, takes careful work, but no computer or micrometer needed.

I have that packing tool @Sarge. And on large truck bearings it’s great but I continue to pack light duty wheel bearings the old fashioned way from a glob in the palm of my hand. And I prefer the red grease.

Personally I really like packing grease into bearings, it was one of the first things I learned in the shop where I started. It’s fun to get that greasy and everything cleans up with soap and water. Rocketman

Haven’t owned a motorized vehicle that required repacking the wheel bearings for about 20 years now. But my pop-up has wheel bearings that I repack at the beginning of each camping season. It’s a little messy…but I know it’s done right. My camper is 10 years old and the bearings and axle look excellent. And I do a lot of camping.

This picture has me a bit confused. Is this the rear axle? If so, why would anyone tighten the axle nut, why would they even remove the housing just for a brake job? If it is a front bearing, is it 4wd or awd? If so, I have the same question, why?

The dealer is always going error on the caution side and Firestone might be correct. I would just have them replaced for peace of mind and eliminate the possible of failed bearing causing injury to myself or others.

If it is a front bearing, is it 4wd or awd? If so, I have the same question, why?

Pretty sure it’s a RWD ONLY Pathfinder.

The appearance of the grease, the patina of some of the metal, and what appears to be galling could be a sign that someone ran an axle nut down too tightly during the brake servicing.
It also appears the bearing had to be cut off; another sign of overheating due to overtightening.