You probably maintain your tracks, filters, and attachments, but did you know that hydraulic fluid quietly destroys pumps and final drives when it’s neglected? Bad hydraulic fluid won’t fail overnight. Its effects are slow, causing excessive heat, accelerated wear, and power loss, until your equipment comes to a complete stop.

In this Shop Talk Blog post, we're looking at what it costs you to keep running your compact equipment on bad hydraulic fluid ... and the price is more than you budgeted for!

Here are a few other Shop Talk Blog posts you might find interesting:

• The Case Drain Filter: A Small Component That Prevents Big Trouble
• Why Rental Companies Trust Texas Final Drive
• 5 Warning Signs Your Final Drive Might Be Failing (And What to Do Next)

Why Hydraulic Fluid Condition Matters More Than You Think

You see, hydraulic fluid does more than just transfer power: it also serves to lubricate components and cool the system. When it starts to break down or become contaminated, everything it lubricates will wear out faster than it should, and the performance of your system will be negatively impacted. Pump failures, travel motor failures, and valve issues can very often be traced back to the condition of the hydraulic fluid.

Varnish: The Silent Killer of Tight-Clearance Components

Varnish refers to oxidized, heat-damaged oil that starts to become sticky and forms a very thin deposit in valves and other internal components. It can lead to sticky valves, which can cause your final drive motors to appear weak or even cause them to become stuck. Another effect of varnish is increased friction that then leads to excessive heating, bearing wear, and further control valve issues. It can also cause case drain filters to clog, which can quickly lead to catastrophic final drive motor damage. In short, varnish can escalate what could have been a simple fluid change into catastrophic damage. 

Water Contamination: Rust, Pitting, and Cavitation

Hydraulic fluid can also be contaminated with water. This happens through bad seals, outdoor storage of the fluid, condensation, and failed breathers.  Water contamination leads to 

• Rusted internal parts
• Micro-pitting
• Reduced lubrication film
• Cavitation

All four of these translate to accelerated wear. That means parts will wear out more quickly, including critical components such as bearings, gears, and shafts, resulting in noticeable power loss. Water contamination can cause bearing and gear damage, potentially destroying pumps and final drives long before their expected lifespan.

Abrasive Contamination: Dirt, Metal, and Sand

Abrasive contamination originates from a variety of sources, with the most common being damaged seals, poor-quality filters, wear debris, and contaminated fluid. Abrasive particles cause so damage because they can circulate through the hydraulic system like sandpaper. This type of contamination scores pumps, gouges gears, and wears out valves. Once abrasive particles enter the system, the only effective way to remove them is through a full fluid flush that includes filter changes. And components like final drives and pumps may have to be replaced.

Oxidation Thickening: When Fluid Turns to Sludge

Sludge is harmful and results from oxidation. Oxidation results from overheating, extended service intervals, or the use of low-quality hydraulic oil. It leads to clogged filters, poor lubrication, increased heat, and lubrication starvation. As with most of the issues discussed here, it also leads to accelerated wear and its domino effect. When it comes to final drive motors and hydraulic pumps, sludge can block case drain lines, leading to seal failures, bearing damage, and complete system failure. It can also blog critical values, leading to a filter bypass. Expect expensive repair or replacement of essential components.

Additive Depletion: When Your Oil Loses Its Protection Package

Additives are essential to your hydraulic system and typically include anti-wear agents, anti-foam agents, anti-oxidation agents, detergents, and viscosity stabilizers. Additive depletion, also known as aging, leads to thinner fluid and the loss of special features, such as anti-wear and anti-oxidation properties. As wear increases, the chances of cavitation increase, and overall system heat rises. And that rise in heat means even faster additive depletion. The results of additive depletion include weak travel power, inconsistent performance, and an increase in friction and internal heat. As with the other issues we’ve talked about, aging hydraulic fluid reduces the expected life of key components like bearings, gears,

The True Financial Cost of Bad Hydraulic Fluid

Bad hydraulic fluid leads to numerous issues, including direct costs such as the repair or replacement of final drive motors and pumps, as well as the time and cost associated with flushing the system. There is also downtime, missed deadlines, and lost work, along with higher fuel consumption and a reduced resale value.

Preventing Expensive Failures

How can these kinds of failures be prevented? Here are some tips:

• Change hydraulic fluid per manufacturer guidelines 
• Replace filters with quality ones
• Keep case drain lines clear
• Take periodic fluid samples
• Protect breathers and seals
• Invest in good-quality hydraulic fluid

Conclusion

Pumps and final drives rarely fail without a reason, and bad hydraulic fluid is often to blame. A little routine maintenance prevents expensive failures and keeps your machine earning money. And remember, you can always contact Texas Final Drive Parts for help diagnosing performance issues before they become costly repairs.