Hydraulic clutch-opinions?

[Steven K]

I am almost at the stage of mounting the clutch and transmission and I figure there is no better or more convenient time to add the hydraulic clutch, but I am curious what everyone's experience is with it. Any opinions, for or against, are welcome.

Thanks.

[FF33rod]

I'll kick off with a couple of the easy comments so the big experienced guys can get to the nitty gritty. Are you thinking hydraulic throw out bearing or external slave cylinder driving the fork? I think most favour the latter although I'm going the former. In either setup, the trick is to get the right combination of master/slave cylinder sizes. FFR's hydraulic clutch option for the '33 provides a 0.75 master, not big enough - 1 or 1-1/8 is the way to go. Has been easy to setup in the build stage, haven't driven it yet...

Steve

[SJDave]

I've my external slave system working for 8 years in my car and have had no issues whatsoever. I was motivated to go hydraulic in an effort to move the pedal box further away to get more leg room in the car. So I used a 1" Master from Tilton to drive the CNC 3/4" slave. This reduces the clutch pedal travel for full engagement to about 5" total. I don't think the effort is bad, but maybe if you have your petite girlfriend driving it she would not be happy.

Everything fails and sometimes by bad luck you get stuck with the 1 in a 1000 crappy part, so that's why I went external, 20 minutes to replace the slave if it every fails instead of days to replace the internal transmission shaft slave setup. At the time, Mike Forte had his system available but it required you to replace the clutch fork....well that puts a damper on it unless your still in the build process. So I made the first adaptor for a standard clutch fork to attach the CNC pushrod directly to the clutch fork without removing it. I send the drawings to Mike and he has improved the design over the years and is very popular. I guess CNC went out of business recently and their slave isn't available anymore, but I'm sure Mike has something else available now.

Routing the cable on the quadrant type mechanical linkage was never clean either, and adapting the quadrant to the Wilwood pedal box was kind of kludge design in my opinion, not very smooth. and with old Wilwood Cast pedals led to twisting the top off the pedal bracket itself. Mine just rotated about 15 degrees but never broke fully.

I wouldn't hesitate to go hydraulic again, but external slave only for serviceability.Pedals and Hydraulic clutch 006.JPGPedals and Hydraulic clutch 004.JPG

[edwardb]

You're listing FFR 3906. So I'm guessing you have a Mustang pedal box? If so that changes things up a little from the more recent builds with Wilwood pedal boxes where the master cylinder already has a mounting location. So you'll need to come up with a solution for that. I personally haven't, but I know some on here have.

I've done two of Mike Forte's external setups and they work fine. He has different brackets depending on your transmission and bell housing. I'm finishing up a build using a Tilton hydraulic release bearing (HRB) and SJDave's concerns are valid. I'm holding my breath. It's not done and on the road yet, but initial feel is lighter and works very well. Certainly was easy to set up. It's in a Gen 3 Coupe and because of the frame design the trans would drop out pretty easily. But obviously hoping that doesn't happen.

For the record, my first build was a cable system on an SN95 pedal box. With the right cable (I highly recommend Ford Performance M-7553-C302 Adj. Clutch Cable. That exact one.) and properly routed (e.g. as smooth as possible, away from heat sources) a cable system can work very well. In my experience, the hydraulic conversions were a little lighter/smoother. But not like it was night and day.

[BEAR-AvHistory]

Have the FORD cable but if you are going to do hydraulic do the tubing early in the build.

[NAZ]

Can't provide info specific to your build but can add a few general comments from my experiences with a variety of clutch actuation methods. First, determining which is best is very much dependent on your application and use. There is no one correct answer to which is best. All have proven reliable if installed correctly.

For a street car, a juice clutch is a good choice. It makes installation easier as routing hydraulic tubing is a no-brainer and if space is tight, the hydraulic T/O bearing has the smallest footprint of all other conventional clutch release methods. However, there are some drawbacks with the hydraulic clutch systems. 1) they are not compatible with all clutch types; 2) they are slower to operate than a mechanical release so it will be slower to shift than a mechanical release; 3) the hydraulic T/O bearing is very sensitive to set-up and if you have too much throw you can push the seals out; 4) the hydraulic T/O also requires splitting the engine and bellhousing to make repairs, which for some cars means pulling the engine & trans.

Mechanical release systems come in two favored varieties: mechanical linkage and cable operated. I've used and worked on both and both are good systems. The cable operated systems are a lot easier to install in a new build, almost as easy as the hydraulic systems. There is nothing wrong with cable systems -- they are the most popular actuating systems on motorcycles and airplanes. The mechanical linkage systems take some engineering to optimize them in a new build and may be beyond what most folks would want to mess with. For drag racing, the mechanical release systems are much faster to operate than any juice clutch commonly found on the market. They are compatible with all common clutches including the Borg & Beck popular with drag racers. They typically are not easy to adjust pedal force like a hydraulic release system. They are simple to maintain and up-front costs are also usually less than a hydraulic system.