Brake Master Cylinder Reservoir Cover Diaphragm / Gasket

This is an OEM brake master cylinder reservoir cover diaphragm / gasket for 1986–1987 Buick Grand National and Turbo Buick applications, designed to seal underneath the brake fluid reservoir lid and help keep brake fluid contained and protected from outside contamination.

This gives you a factory-style replacement option for freshening up your original brake reservoir setup without swapping out unnecessary parts.

⬛ OEM Part – Factory Brake Reservoir Seal

Why You Want It
Because the little rubber pieces matter. This diaphragm/gasket sits under the brake fluid reservoir cover and helps the lid seal properly. Over time, the original gasket can get swollen, hard, distorted, cracked, or weak from age and brake fluid exposure. When that happens, you can end up with brake fluid seepage around the reservoir lid, moisture getting into the system, or just a messy engine bay around the master cylinder.

If you’re restoring, servicing, or cleaning up the brake system on your Turbo Buick, this is one of those small OEM pieces that helps keep everything looking and functioning the way GM intended. Perfect for someone trying to keep their Powermaster brake setup complete, correct, and original.

This is an OEM used part with normal wear from age and use. Please review all photos closely before purchasing.

All parts are sold as-is with no returns, refunds, or exchanges. Buyer is responsible for verifying fitment for their specific application prior to purchase. Turbo 6 Parts makes no performance guarantees. All sales are final.