New Engine Bay Grommets

Today I installed all new round rubber grommets throughout the engine bay.  Four months ago I removed all the dried up old grommets and measured them so I could procure fresh new replacements. There are 14 total grommets in six different sizes in the 320’s engine bay. I was able to buy new ones from McMaster Carr in all the sizes I needed, though I had to buy full bags of each size, since they don’t sell by the piece.

I worked my way around the engine bay from the front driver’s side toward the firewall and around to the front passenger side, installing all the new grommets as I went.
First was a 3/4″ diameter hole at the front-right on the lower inner fender.

Next, slightly back on the upper fender a smaller, 5/8″ hole for wiring to the signal lamps.

Since there were wires coming through, I cut the grommet using a pair of scissors to accommodate them.

Then I just put the grommet into place and used some rubber cement to glue it back together around the wires. I found the key to using rubber cement successfully in this application was to apply a very thin coat to both cut ends of the grommet, wait for the cement to dry, and then press the parts evenly together and hold them together for at least a full minute.

Next, further back a bit lower on the inner wheel well was a 1 1/4″ diameter hole for the hard fuel line from the fuel tank. No cutting necessary; I just popped that one over the end of the fuel line.

And further back and down lower was another, slightly smaller 1 1/8″ hole for the hard brake line for the front wheel.

Next, back on the firewall, was the choke cable, which comes through a 3/4″ hole, and the hole for the hood release rod, which was 1/2″.

I cut the grommet for the choke cable and slid it over the cable and onto the firewall.

Then I did the same for the hood release.

I replaced two grommets at the corner of the firewall and engine bay. The lower was 7/8″ in diameter and the upper 1 1/8″.

And on the other side of the steering column moving toward the center of the vehicle, I installed another 5/8″ grommet around the accelerator cable.

Next, down a bit lower on the firewall and continuing across toward the other fender were the pair of holes for the heater core supply and return hoses, which are 1 1/8″ in diameter. I used my needle-nose pliers to pull out the remnants of the hose from the lower outlet.

Then I used the pliers to pull out the grommet…

…and installed two new ones.

Next, on the inner fender passenger side just between the firewall and the battery shelf I installed a new 1 1/8″ diameter grommet around the brake line, again cutting and rubber cementing it around the line.

Further forward, behind the front end of the batter shelf on the upper fender I pressed in a 5/8″ grommet around the signal lamp wires similar to on the opposite fender.

These new grommets make a big difference in the functionality and the appearance of the engine bay.

When I ordered my new grommets the minimum lot size (bag) ranged from 25 to 100 for the smaller size grommets. I actually sold a handful of kits I made by bagging up the surplus grommets in each size, labeling them, and providing an engine bay map of where they go. I may still have some grommets leftover, so f you have interest in buying such a kit, just shoot me an email.

Steering Column Grommet Removal

Today the weather warmed up a bit and I was able to get outside and do some work on the truck. I pulled the steering column grommet out of the firewall. Mine is in really rough shape and I’d like to replace it, though I haven’t had much luck finding a replacement part.
Here’s the engine bay:

The steering column grommet is a boot that mounts into a cone-shaped hole in the firewall and has two holes; one for the steering column and another for the shift linkage column. I’ve seen pictures of some of these in decent shape. They angle downward parallel to the steering column outwards an inch or so. Here’s a close-up of what remains of my grommet. The bottom lip part that mounts into the firewall is intact, but the boot section that encloses the columns is gone.

I used a flat head screwdriver to pry the grommet from the firewall opening.

Clearly the grommet wouldn’t come free without removing the steering and shifter columns, so I cut the rubber with a pair of scissors.

Then I was able to pull it off.

Here are some detail shots of the top and bottom of the steering column grommet.

Here is a close-up of the profile of the grommet where it mounts to the firewall.

Engine Bay Grommets

I plan to replace all of the firewall and fender rubber grommets in the engine bay. Some are just missing and others are dried up, crusty, or falling apart. The first step was to inventory all of the holes in the engine bay that need grommets to get a sense for what size I need to order and the quantities of each.  I used my calipers to measure the diameter of each hole in the engine bay so I can get the right sized replacements.
This post serves as a photo record of the engine bay grommets, starting in the front driver’s side corner, working my way back around the firewall toward the passenger side and back down the inner fender on that side. The area with torn metal that is bare in spots I believe is where the fuel filter bracket originally hung.
The first was down on the lower inner driver’s side fender.  The diameter of this hole was 3/4″

Moving back in the direction of the firewall, another grommet in the fuel line hole just over the wheel well.  This hole was 1 1/4″ in diameter.  Also shown in this photo, further back on the same fender from the fuel line grommet (near the steering column linkage) was another grommet in a hole in the fender with a 1 1/8″ diameter.

In the upper firewall above the shelf and next to the hood hinge, there was another grommet, this one in 1 1/8″ diameter hole.  Shown also in this picture is another hole, located to the right of the first one in the upper fender (without a grommet).  That hole was 7/8″ in diameter.

Then, pictured just to the right of the master cylinders, two small holes for the hood release (1/2″ diameter) and choke cable (3/4″).

And another small one on the other side of the steering column, 5/8″ in diameter.

Two grommets for the heater core inlet and outlet, each 1 1/8″ in size.

There were two more large holes in the firewall to the left of the heater core. I later determined that these were not original, had been drilled by a previous owner, and plan to weld them up.

On the passenger side of the engine bay, also up high above the fuse box near the hood hinge, was a larger hole with grommet for the engine bay wiring harness.  That one was 1 1/8″.

Another hole was located in the lower fender with grommet for the brake line.  That hole was 1 1/8″ in diameter.

And closer to the front of the engine bay in the upper fender over above the battery shelf, was a small 5/8″ diameter hole and grommet.  Not shown, there was another hole identical in size to this one on the opposite fender.

Below is a diagram I created of all of the engine bay holes that require grommets in my 1964 L320. The letters represent the different grommet sizes.  This should be reasonably consistent with 320s from other years.