Hi All,

A leaky beehive pedestal to engine connection on my 83. At least I hope it's that. I've seen a thin film of oil own the side of the engine for a bit and I'm think it's this rather than dowel pin.

I was looking for beehive o-ring and crush washer specifications and could not find any definitive details. I did find other threads here, general info elsewhere, but nothing that included complete information. So here's this, backed up with measurements and photos that haven't been deleted from our nebulous cloud. This post is meant to clarify refurbing the pedestal to engine interface. I am not planning to loosen fasteners where the manual says "never loosen".




1. Beehive pedestal to engine block. The engine block interface is machined flat and the pedestal has 2 machined receptacles for the o-rings. The dimensions of the receptacles are 19.8 mm in diameter and 1.6 to 1.7 mm depth.
The nuts attaching the pedestal to the studs are 10mm. The front is easy to get and the one near the firewall a bit of a challenge. They are not tightly torqued from the factory. I used a 10mm combination open ended/box wrench about 6" in length. That gave me enough swing reaching from under the car to loosen the rear most nut. That's a 12mm bolt at the other end, threaded into the engine.



2. The old pedestal o-rings were compressed to 1.7 mm in thickness and had expanded to the full diameter of the receptacle, 19.8 mm. The new o-rings are 19.2 mm OD and 2.6 mm thick.

Some other threads recommended getting a McMaster Carr part that is 15 mm OD with 2.5 mm thickness. Those would be way too small! The proper size is 15 mm ID with 2.5 mm thickness and resulting 20 mm OD. Here are links to resources where you can buy these

McMaster part # 1185N99 https://www.mcmaster.com/1185N99/
Grainger part # 713N13 https://www.grainger.com/product/O-R...-Inside-713N13
Harbor Freight, #A114 part of the $10 Viton kit (slightly larger as they are imperial sized and = 15.8 mm ID with 2.6 mm thickness.
Atkins, https://www.atkinsrotary.com/Oil-Sys...4-10-1601.html
And presumably, Mazda dealership?

I'm choosing to use #A114 from the HF Viton kit, despite being slightly larger. I tested this size, A114, in a Buna rubber version, 70 Durometer, I had on hand. They fit really nicely but the temp rating was only 100°C, too close to our oil temps. The HF Viton kit is rated for temps up to 400°C. And I'm keen to just buy them rather than mail orders.

Here's a test photo of the A114 sized ring with a 1/4" plexiglass plate screwed down using the 10mm nuts. They fill the space nicely, provide a nice thick seal, and don't block the passages at all.



3. Banjo Bolt Crush Washer Size

The exact size is 18 mm ID x 24 mm OD x 1.5 mm thick in copper. I have an Amazon kit with that exact size but in aluminum.

HELIFOUNER 560 Pieces 18 Sizes Automotive Drain Plug Gaskets, Oil Crush Washers, Aluminum Flat Washers Assortment Kit (M6 M8 M10 M12 M14 M16 M18 M20 M22 M24)
A huge thank you to @lwrobins for the suggestion to use a 23 mm crow foot attachment to break loose the banjo bolt.

 

Mazda number is 9954-10-1601. the list price is $6.63, Mazda comp is almost half that