Grommet for Through Pedal Box Hydraulic Lines

[mach'er]

I found this grommet (Danchuk 820, for a 55 Chevy), and ordered one to see if it would work.

http://thefactoryfiveforum.com/attachment.php?attachmentid=79399&d=1516143681

Lo and behold, it is almost perfectly sized for the clutch cable hole in the firewall (which I'm not using, since I've gone to a hydraulic clutch):

http://thefactoryfiveforum.com/attachment.php?attachmentid=79398&d=1516143506


All it needs is the holes drilled out a hair larger than as delivered.

Anyone have a smart and successful way of drilling/reaming out holes in rubber? I ruined the one I ordered, but it fits so good, I'm willing to try it again.

Or, does someone have a better method of creating a sealed pass through for three reservoir 1/2" hoses (two brake, one hydraulic clutch) and one brake line? I thought this could work great, but am willing to look at other ideas.

Thanks!
--Curt

[NAZ]

I've used a small sanding disc and small grinding stone on rubber and urethane products with good results. I've never had any luck using cutting tools like a drill or reamer but grinding or sanding works. As a machinist I used to precision grind urethane rolls for coating applications. It grinds easy but won't cut to save your life.

[michael everson]

try freezing it before drilling it
mike

[JoeAIII]

A punch, like used to cut holes in leather or fabric to install grommets may work as well. Similar to these https://www.amazon.com/SE-7909LP-9-Piece-Hollow-Leather/dp/B0002964CC
I have used them to cut holes in rubber sheets before.

[Thunderball]

What Mike said. Leave it in the freezer overnight, chuck it up in the vice, high speed low pressure on the drill. Should be a clean hole.

Chris.

[CDXXVII]

If that ends up not working out you could just use three separate grommets. Separate grommets made my install pretty simple and clean.

http://thefactoryfiveforum.com/attachment.php?attachmentid=79415&d=1516209400

[mach'er]

Thanks for the responses. I'm going to give it another go, or two, using the suggestions here. If it doesn't work out, I'll go the separate grommet route.

I'll post a picture in my build thread of whatever I end up with.

CDXXVII: I see your lines from the reservoir to the master cylinders. Where'd you choose to route the pressure lines (including to the clutch slave cylinder)? I don't see them coming out in that picture - but it sure looks like a clean and well thought out layout. Also, I like your braided lines. Nice!

[jrcuz]

Here is my solution.
JR