What's the clutch drill mod?
 

Can someone tell me?

Re: What's the clutch drill mod?
 

I believe the drill mod you are refering to is done when an aftermarket master cylinder is installed. To do it you just widen the opening of the end of the hydrolic line that connects to the master cylinder by drilling it out slightly. I forget the size bit that is used, that information should come with the new master cylinder. Also, if I remember correctly the depth of the bit should only be about 1/4 inch, not sure exactly. Hope this is helps and answers your question.

Matt <img border="0" alt="[cheers]" title="" src="graemlins/gr_cheers.gif" />

Re: What's the clutch drill mod?
 

You can also do this to a non aftermarket clutch assembly as well I believe. It is to help get a little better clamping force in the clutch especially at higher RPMs where the stocker fails miserably. You can check out installuniversity.com or searching over on this board.

Re: What's the clutch drill mod?
 

From what I have heard. drilling out the line, lets the disk ingage and disingage faster. There will be less slipping because you get a fast, hard, clamp.

Re: What's the clutch drill mod?
 

Check out this web page. Gives a pretty good description of what to do.

Drill Mod

Click on modifications and then scroll down.

Re: What's the clutch drill mod?
 

The drill mod opens up a restriction in the line between the clutch master cyl and the throwout bearing. The factory line has a .062" orifice built in. I opened it up to .125 - this allows the fluid to return faster. If you make 3 consecutive quick shifts on the stock line the oil stays in the throwout bearing and prevents the cluth from clamping completely. This is the cause for a lot of failed clutches. The master is a bitch to get out because it's under the brake booster. The line disconnects from the throwout bearing by pushing in on the release ring. Make sure you have bled the line well before you re-install. Several people have had to remove the thing twice just to get it bled.I'm not sure if this applies to te aftermarket clutches or not.I first read about this in GMHTP magazine.