firewall grommet - heater valve pipes

[digger]

I am reinstalling heater box. What is the trick with install of the firewall grommet? it looks like it is design to be installed from inside.

If I install it on firewall first the aluminium pipes push it out into the engine bay as can’t quite get the angle right to hit the holes.

if I pre slide it on the tubes then getting it seated is very difficult as with a RHD car there is a bracket in the way for the brake transfer lever so only have minimal access to manipulate

[varg]

It's definitely meant to be installed from the inside, flange on the inside of the firewall, semicircle cutout on the bottom. Like the engine harness grommet, it has a groove that is tough to get mated with the sheet metal without pushing it into its spot then going around to the engine side and pulling at it around its perimeter to open that groove and get the sheet metal seated in it. To keep the pipes from pushing it out I would lubricate them with soap, worked for me. Maybe have someone put hands on the grommet from the outside to counterhold the pipe sleeve portion of it as the pipes push through? I can't visualize the RHD obstructions to know if this is an issue.

[moatilliatta]

/\ + I usually put some sil glide / silicone lube on the grommet and the pipes.

[ghrays]

I found it’s definitely a two-man job. The only way I could get the grommet to seat was to install it first, from the inside, and then gently push the heater pipes through. It took several attempts.

[digger]

i ended up installing from engine side i.e. in reverse. it was a new piece so pliable enough.

the reason i couldnt get the pipe angled to get through the hole and it kept gettting pushed out despite being lubricated was it was a new foam gasket thats much thicker than the old one so the whole box sits too low until the thing is bolted home.

[slippery]

I just did this last month. Total pita. I installed it from the engine side as well.