Clutch Master Help

**Frozen WS6** · 06-19-2007, 06:27 PM

I was wondering if anyone knows were I can buy a new GM clutch master cyl. with the drill mod already done to it. I asked one of my local Pontiac dealers and they claimed they have never heard of the drill mod. Thanks in advance.

**Eagle** · 06-20-2007, 06:45 PM

LOL! Drill mod? I've never heard of it either... clue me in?

**2MuchFun** · 06-21-2007, 05:08 AM

heard of it dont know what it is and would like to know because im replacing master & slave cylinders when i put my new clutch in

**2MuchFun** · 06-21-2007, 07:30 AM

AHA i found it on installuniversity bassically the drill mod makes the master cylinder line bigger, allowing more flow i guess

This step is known as the infamous "drill mod". The same modification can be found in numerous publications and bulletin boards over the internet. If you don't want to perform the drill mod, which at this point would be a pitiful shame because it only takes a minute to do, skip this step and continue on to Step 18.

You should now be left with the steel braided line as shown in Figure 16. We took a small piece of cut up vacuum hose (anything thick and flexible will do), and wrapped it around the brass part of the fitting on the steel braided line. Then we clamped down on it with a set of vice-grips to hold the line while the restriction would be drilled (see Figure 17). Take a 1/8" drill bit and slowly, constantly bringing the bit back out and then back in to remove metal shavings as often as possible, drill out the ingenious in-line restriction (lots of sarcasm) that GM decided was best for your blessed muscle car. You will have to drill until you feel the drill bit pass through the restriction. The bit should freely move into the line before you are through drilling. The total distance drilled will be in the neighborhood of one inch (1"). Also, while drilling, be sure to keep the steel braided line as straight as possible so you don't drill through the line by accident. This sounds like a lot to accomplish, but common sense will carry you through. ;-)

http://www.installuniversity.com/ins..._line_show.jpg
http://www.installuniversity.com/ins...line_clamp.jpg
http://www.installuniversity.com/ins..._drill_bit.jpg

17. Now that you have the restriction drilled out you will need to flush some fluid through the line in order to remove any excess shavings left behind. You will need to press the end of the quick connect fitting down while squirting fluid onto and in the quick connect fitting as shown in Figure 19. This will allow fluid to flow down the line and wash out any excess shavings keeping them from entering your hydraulic system as shown in Figure 20. Be sure you have a rag to catch the fluid and metal shavings at the end of the line. We used a bulb syringe which can be acquired for a few dollars at most any local auto parts store.

Figure 19 http://www.installuniversity.com/ins..._flush_top.jpg

**2MuchFun** · 06-21-2007, 07:31 AM

heres the write up.......but its for a mcleod master cylinder, not sure if it applies to gm cylinders http://www.installuniversity.com/ins...r_cylinder.htm

**SSwt00SS** · 06-21-2007, 08:46 AM

you won't find a master that has the drill mod done to it new, PERIOD. the drill mod is what you do to the master cylinder...

**Eagle** · 06-21-2007, 10:44 AM

and why would one want to drill out this restriction? My factory clutch behaves just as I would expect it to... perhaps its only useful to folks that have heavier pressure plates installed?

-Eagle

**2MuchFun** · 06-21-2007, 03:53 PM

drill out the ingenious in-line restriction (lots of sarcasm) that GM decided was best for your blessed muscle car.

my guess is it makes the clutch slightly easier to push..........im gonna do it.

**Frozen WS6** · 06-21-2007, 06:41 PM

you won't find a master that has the drill mod done to it new, PERIOD. the drill mod is what you do to the master cylinder...

I know it is a mod that I would need to do. I'm not totally stupid. I just want my car to quit driving through the clutch. First off I don't have the time or experiance to do it myself, I've done alot with mechanical clutches, but not hydrolic. Second I live in the middle of no where and no one up here has a clue as to what I'm talking about. That is why I want to know the name of a good speed shop, or tranny shop that could get me a new GM master, then do the drill mod, and then send it to me. Or do I need to spend over a thousand dollars to fly down south to get in someones face to get things done, and so I don't get screwed.

**SSwt00SS** · 06-22-2007, 08:49 PM

Originally Posted by Frozen WS6

I know it is a mod that I would need to do. I'm not totally stupid. I just want my car to quit driving through the clutch. First off I don't have the time or experiance to do it myself, I've done alot with mechanical clutches, but not hydrolic. Second I live in the middle of no where and no one up here has a clue as to what I'm talking about. That is why I want to know the name of a good speed shop, or tranny shop that could get me a new GM master, then do the drill mod, and then send it to me. Or do I need to spend over a thousand dollars to fly down south to get in someones face to get things done, and so I don't get screwed.

eh, welcome to my world. plenty of mechanical clutch experience and exposure, but the Ls1 hydrolic clutch is a new one for me as well. IMO, i would just order both a new master and slave and then follow the drill mod instructions, as i have read them over and it's very detailed, save yourself a few bucks and do it yourself. i know when i get ready to do a clutch swap, that's what i will be doing. good luck and wish you the best when the time comes for you to change out your clutch....

**Frozen WS6** · 06-23-2007, 11:45 AM

Thanks SS. But last summer I had a new pressure plate, clutch, and flywheel asm. installed and now 4,000 miles later it's toast. I drive like granny. I shift at 2,000 to 2500 rpm and rarely turn it above 3,000. the only thing we didn't replace were the hydrolics. My therory is that the master and line restrictor is not allowing the fluid to move properly and causing the clutch to not fully lock up/ hook up and is always slipping. It will always drives right through the clutch, even if I excellerate to pass someone around town or on the highway.

**2MuchFun** · 06-23-2007, 01:34 PM

talked to a mechanic on the corner from me, he said he would replace my clutch for $325 labor.........and said while you have it apart, might aswell replace the master and slave cylinders........

dunno i might still do it myself, but im def. replacing master/slave cylinders while im at it, only $60 apiece give or take $20

**Frozen WS6** · 06-24-2007, 08:41 AM

Yeh, I should have done it with the clutch. But I had just about maxed out the old credit card on a new tranny for my truck. Which will always get priority, since I will never drive the bird in the snow. I have 7 months with snow on the ground.
[QUOTE][talked to a mechanic on the corner from me, he said he would replace my clutch for $325 labor.........and said while you have it apart, might aswell replace the master and slave cylinders........
I wish our prices were that cheap. The price of the parts cost alot more than that up here. Thanks to the high freight prices.