In this Shop Talk Blog post, we are going to look at one of the most damaged final drive motors we have seen -- and we have seen plenty here at Texas Final Drive. The majority of the damage can be traced back to the rotator group.

Here are some additional Shop Talk blog posts you might be interested in:

• Excessive Noise Troubleshooter Guide
• How to Troubleshoot a Noisy/Vibrating Final Drive
• Preventing Case Drain Related Failure

Internal Explosion?

This is the axial piston final drive motor whose rotator group was more damaged than anything we’ve seen. Shattered piston shoe fragments and chunks of metal of all sizes -- that is a nightmare failure mode for a final drive motor. Our autopsy of that final drive showed even more damage, but this is one image that we won’t soon forget.

Chewed up Piston Shoes

When we opened it up, we saw these horribly scarred piston shoes. It’s not unusual to see abrasion on piston shoes if the motor has been exposed to hydraulic fluid contaminated with abrasive particles. But this goes beyond abrasion and scarring to what looks like a monster chewed on those piston shoes. However, we still haven’t reached the worst of what we found inside this final drive motor.

Broken Retainer Plate

You might notice in the image above that the retainer plate is missing. Well, not exactly missing -- we found it -- in pieces. As you can see below, it looks like the retainer plate simply shattered. If you look closely at the broken ends of the retainer plate, the break looks fairly clean, indicating a more brittle failure mode.

What Happened to This Final Drive Motor?

Now to figure out what happened first. Was it the retainer plate that failed first, leading to the scarring of the piston shoes and their removal from the pistons? Or could you see a different course of events leading to this damage? If you can, let us know your thoughts in the comments.

And why did the retainer plate fail the way it did? Thoughts?

Totaled

Needless to say, this final drive motor was pretty much totaled. The damage from having piston shoes and pieces of the retainer plate moving around inside the hydraulic motor while it is running did significant damage and takes the concept of contaminated hydraulic fluid to an entirely new level.

Warning Signs

This type of damage does not happen overnight, and we can be fairly confident that there were some very strange noises and possibly vibration at the beginning of this failure mode. As things grew worse, this drive motor would have lost significant power and that is probably the reason why it was brought it.

Lessons Learned

If your final drive loses power or makes odd noises, you need to get it checked out rather than trying to keep running it. What may start out as a simple problem can escalate into a total disaster if you ignore the signs that something is going wrong.

Texas Final Drive is your partner in providing new or remanufactured final drive hydraulic motors from a single mini-excavator to a fleet of heavy equipment. Call today so we can find the right final drive or hydraulic component for you, or check out our online store to find your O.E.M. manufacturer brand motor now.