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Backing plate gaskets, also called axle flange gaskets, help isolate your vehicle’s differential fluid from its wheels and brakes.



What are Backing Plate Gaskets?

When you remove the wheel hubs from a solid rear axle, you’ll find backing plate gaskets between the hubs and the axle. There’s one backing plate gasket per side. It’s a good idea to replace these gaskets whenever you service or replace your vehicle’s rear wheel bearings. If you own a 4x4 with solid axles mounted front and rear, you likely have four backing plate gaskets rather than the standard two found on rear-wheel drive vehicles.

How do Backing Plate Gaskets Work?

Not all vehicles have backing plate gaskets. Front-wheel drive vehicles don’t have a rear differential, making backing plate gaskets unnecessary. Because metal parts don’t fit together perfectly, gaskets are often necessary to preserve the life of your vehicle’s components. Backing plate gaskets accomplish this task for the drive axles on vehicles equipped with solid axles, like older rear-wheel drive cars, trucks, and 4x4s.

How are Backing Plate Gaskets Made?

Backing plate gaskets may be made of paper, plastic, rubber, or composite material. It’s easy to replicate paper gaskets at home with a razor blade and some gasket making material. If your gaskets are made of plastic or rubber, it’s best to purchase factory or aftermarket replacements.

Why do Backing Plate Gaskets Fail?

  • Like all gaskets and seals, backing plate gaskets eventually wear out and create leaks on the components they’re supposed to protect.
  • Age, oxidation, and heat add stress to gaskets.
  • Improper installation is a leading cause of premature gasket failure.

What are the Symptoms of Backing Plate Gasket Failure?

  • You may notice differential fluid near your wheel hubs or other suspension components.
  • Your differential fluid may read low during a routine check.
  • If gear oil contaminates your brakes, they may fade quickly and produce smoke and noise whenever you press your brake pedal.

What are the Consequences of Backing Plate Gasket Failure?

  • In extreme cases, your rear differential may run completely out of fluid, making costly repairs necessary.
  • It’s unsafe to operate a vehicle after the brake pads become contaminated with gear oil
  • Topping off differential fluid can be cumbersome at best. Frequent top offs add to the time and expense of maintaining your vehicle.

Leaks need to be diagnosed and repaired as soon as possible to avoid costly repairs in the future. Small problems tend to become much bigger problems if they are ignored. If your vehicle leaks any of its fluids, and you’re not sure how to fix the problem, call your local Pep Boys and schedule an appointment before the issue worsens.

If you have questions or concerns about backing plate gaskets or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.