What is the best way to get the 3 hole, 4 hole, and speedometer grommets in the fire wall. The holes seem awfuly small. Do you install in the firewall and then put the hoses in the grommets?? Also, how do you get the backup light switch cable connector thru on the 4 hole grommet???

thanks

 

Not sure if this is the correct answer...but i just ran my new battery cables last night and had to deal with the battery box grommets. I also cut a new hole and inserted a universal one wire grommet for the ground cable.
In order for the grommet to provide a water tight seal I found it easiest to put the wire thru the grommet then thru the hole. Once I had the wire to the location and length that i wanted it I pushed the grommet down the wire to meet the box/firewall. I then worked the grommet into its location with a blunt flat head screwdriver. Took some patience and elbow grease but it worked out very nicely. Water tight seal.
I would imagine if your wires weren't so tight in the grommet that you could install the grommet first and then snake the wires thru. Just keep an eye b/c if you pull to hard or quick you could pull the grommet right out of the firewall without much effort.
I would recommend some clear silicon gasket around the wires and grommet just as insurance once everything is finalized. If you have 5 wires and a 4 hole grommet chances are that 5th wire is meant to travel thru the firewall somewhere else...but you can feed it thru the grommet next to another wire in the same hole depending on wire size then just cover it with silicon gasket.

 

Your best friend for this is Dawn Dish detergent, it works great on lubricating grommets and the like.