Remove relay box cover?

[Chris B]

I'm prepping for the 1000 hr inspection, which requires getting inside the relay box to check the battery relay connections. However, I can't see how to remove the relay box cover. The big problem is access to a 10mm hex-head bolt on the right (outboard) side, directly behind a huge (/immovable) bundle of wires penetrating the firewall.

Hopefully I am missing something stunningly obvious! But how does one remove the relay box cover??

Chris

[Steve]

Chris:

You're right - it is almost impossible. I have had mine off twice: once to replace a starter relay, and at the last annual, to install the BatteryMinder harness. You can just barely get an open-end wrench on it and by repeatedly reversing the wrench, loosen it. You don't have to remove it, just loosen it a few turns. The relay cover is slotted on that side. Good luck,

Steve

[Chris B]

You can just barely get an open-end wrench on it and by repeatedly reversing the wrench, loosen it.

To close the loop on this, I was unable to replicate Steve's feat with any open-end wrench. At least on my aircraft there was simply not enough room. Presumably there are variations in assembly? Or maybe I am just not very clever.

In case others struggle with this problem, a modified ratcheting box wrench ($11 at Amazon) did the trick, per the pictures below.

Note that in addition to the retaining bolt from Hades, the right magneto, several wire clamps & the oil filter must be removed to extract the cover from the engine bay. Serviceability was definitely not high on the priority list when this was designed...

Chris

*****************

Here is the problem:

The initial wrench modification:

Unfortunately, the ratchet head still interfered with the tapered aluminum flange around the wiring bundle.
Some additional sanding fixed the issue (note that both the front and back sides of the wrench are sanded for clearance, since for installation the wrench is reversed):

Here is the wrench in action. There is just enough room for one 'click' on the ratchet (5 degrees):

[Steve]

Chris: Your invention is great! Looking at your photos, it appears that your aircraft has a different design than mine does for the cover. As bad as I thought mine was, yours looks worse.

Steve

[rwtucker]

Fantastic Mod work Chris!

[Charles]

Wish I had seen this thread before tackling this task. After much head scratching, a flex-head ratcheting box end wrench (unmodified) did the trick. Set it at a 90-degree angle and access the bolt from underneath the cable bundle. Hold it in place with a screwdriver wedged between the cables and the bolt, and turn the wrench using pliers to gain leverage given the 90-degree angle. We were able to get 3-4 clicks per turn. We’ll need to go back in there in a few weeks, I’ll try to post a picture.