View Full Version : grommit question

08-05-2006, 03:46 AM
My 3rd question of the evening is a grommit question
I'm missing several of the rubber grommits (sp?) that go around cables passing through the firewall. I have some replacements, but my real question is, what is the trick to getting those things in place? And do the grommits have to be in place first before cables are passed through, or can you slide the grommit over the cable and then work it into place? Does the difficulty of the task decrease proportional to an increase in swearing?

08-05-2006, 06:05 AM
Well, Wallace, first get some cheese......
I've found it easier to install the grommet on the cable first. A little dishwashing liquid will help sliding the grommet on the cable, and in working it into the hole in the firewall. It'll also give your engine bay a nice lemon fresh smell.
A Popsicle stick tapered to a blunt edge can be a handy tool to help with the really stubborn ones.

08-05-2006, 09:17 AM
I spray with WD40, then fold them in half. Place one edge of the grommet into the hole and work it around. If a portion of the lip folds over, finish that with a small flat blade screwdriver after the grommet is seated in the hole. For speedo/tach cable, you need to push the nut through the grommet (WD40 helps) before installing it in the firewall.

08-05-2006, 05:16 PM
Just watch out for those were-rabbits!


08-05-2006, 11:03 PM
If the grommets are missing, but the wiring is all attached, there is no way to get the grommet over the wire as far as I can see, unless you cut the grommet.

I have the same problem. I am missing two grommets from the firewall, and I don't really want to disconnect the wiring harnesses to get them on. So I have the grommets, and I am just about to cut one radius, wrap it around the wire harnes, and then try to manouvre it into place. I can't see any other way.

A split new grommet is better than no grommet I would think.

08-06-2006, 06:14 AM
A neat trick for firewall grommets where no rubber grommet exists is to use black butyl rubber rope caulk . The stuff usually comes in strip form, about 1/2" diameter, and will adhere to itself. I have used it to form around the wires (or in the case of the wiper actuator arm) and mould it to fit snuggly within the confines of the hole in the firewall to be filled. Looks just like a grommet after you mould it to shape (use a little spit on your fingertip to smooth it up) and frankly seals better than any grommet you will find. I have used it where the grommets have failed from age (all of 3 years) and just clip out the rubber grommet and make my own out of butyl rubber. Most NAPA stores carry this product.


08-06-2006, 11:27 PM
Thanks all for your suggestions. Bill, I like that idea! I had been toying with the idea of using some vinyl polysiloxane impression material! I think I'll try the butyl rubber instead. Thanks! Do you suppose plugging all those holes will have much impact on decreasing cabin fumes?

08-07-2006, 02:25 AM
I had exactly the same problem when I bought my TR6, not one firewall grommit left. I plugged these, but still had fuel fumes in the cabin. I found that the fuel pump was 'wet' in places causing the smell to fill the boot and finally come thru into the cabin. I taped up the rear end internally with pvc sheet and put the trims back over this. Stopped the smell comming thru. I'll get to the pump shortly. I might replace this with a new Bosch pump.

08-07-2006, 05:29 AM
I had been toying with the idea of using some vinyl polysiloxane impression material! I think I'll try the butyl rubber instead.

[/ QUOTE ]

That is a dentist inside joke, folks. Don't try this at home!
Talk about an expensive fix!!


08-07-2006, 11:23 AM
Bill- that BVBRC that you mention . Would it be a good sealant for the wiper arm access pieces under the dash. Where did you get it?

08-07-2006, 11:51 AM
Don, if you are referring to the little "doors" way up under the dash, I would think that any good caulk rope would work. The butyl rubber rope doesn't compress easily and would be tough to use as a sealant sandwiched between two pieces of metal, if we are on the same page.

I think they use this stuff to seal or caulk windshields and the like. It is relatively rigid and smooth, adheres to itself nicely to make a donut and stays put afterwards. I got mine from a local NAPA automotive retailer. I know that NAPA is a national chain so you should be able to find it wherever. Another good source would be a professional automotive paint supplier, like PPG or the likes.

Wait! I went outside in my workshop and found the box! It is a NAPA/Martin Senour product, called PRO Glass Setting Butyl Tape, product #4196, 3/8" X 15' roll. There. I hope that helps. Works great!


08-07-2006, 01:56 PM
thanks, still trying to find something to use on them dang "doors".

08-07-2006, 05:27 PM
Just use caulk strips. That is what came off of mine. I resealed them with silicon.


08-07-2006, 05:38 PM
didn't like the silicon idea if I had to take them off again.