Hydraulic clutch conversion

Discussion in 'Classic Mustang Specific Tech' started by RTGreen, Sep 27, 2007.

  1. I know this is a mustang forum, but I've rarely found other sites that can help with old fords like this one.

    I have a 1972 Gran Torino with a Toploader 4sp and 351C. I would like to swap to a hydraulic clutch to free up some space for some Hooker Super Comps. Is there a do it yourself way to do it with salvage yard parts? Or does some one sell a conversion kit?


  2. hey, Ctrl-v and I don't have to type much, sweeeeet one more post:D :D


    Seriously, there are two proven ways to do it.

    JMC unit (400bux) or source together your own kit from CNC parts. The preceding thread describes those two options plus some junk yard tech. More than one member around here has a web page describing their home brew solution.

    Rots o' ruck
  3. I did it using a girlock (or was it girling?) 1.375 stroke 0.70in bore master cylinder coupled with a PBR 0.75in slave cylinder from an XB falcon. I took heaps of photos of the whole setup. The m/c is mounted where the clutch rod would go through the firewall with 2 bolt holes and a reinforcing plate.

    If I didnt make mistakes with part selection prior to that it would have been fairly inexpensive (a lot less than the JMC setup).
  4. One thing I have not seen on any of these threads is a measurement of how much travel is obtained at the fork/slave cylinder. Using a 3/4" MC bore and the CNC slave with a 7/8" bore, I get a maximum of 3/4" of travel at the fork with very little pedal effort. Several people have reported that this combination worked fine. Unfortunately, it doesn't disengage adequately on my car. I tried a 3/4" (Honda) slave that did disengage, but with no mechanical advantage in bore sizes, the pedal was rather stiff. Question now is: how much travel is required at the fork to disengage the clutch properly?

    Late model style bell with "pull" type clutch fork, Centerforce II pressure plate. I really don't want to go back to the 3/4" slave.
  5. There is also the Hyd. throw out bearings which will give you great pedal feel just make CERTAIN you pay close attention to the travel limits and install a pedal stop or you'll have your transmission out like I do now.....:nonono:

    With this t56 there was no room for external cylinders but if you have room I'd investigate that as you can work out those much easier.
  6. I was going to suggest the hydraulic throwout bearing too. I have a McLeod on the T-5 in my '65, with the JMC master (which is merely a CNC master with a different bracket welded on, to achieve the correct angle with the Mustang firewall.

    One thing no one has mentioned is that the toploader clutch fork is a "puller" (when viewed from the tailshaft) and the T-5 and T-56 are "pushers." Another is that toploaders don't have the ears in the case that the T-5 does, to mount a bracket for a slave cylinder. Where there's a will there's a way, I suppose. It's possible to mount a bracket on the bell housing and use a pusher slave. It's also possible to mount a puller slave (CNC does make one) on a toploader case, although welding might be required. Whatever you cobble together has to be strong, though, since the slave has to exert, I dunno, about 100 pounds force on the clutch fork, a few hundred thousand times in the life of the car.

    The challenges of using a slave on a toploader might explain why the kit JMC offers for the toploader uses a hydraulic TO bearing. Likewise the Tremec.

    Question to Shankin66: I don't have the pedal stop with my McLeod TO bearing. What happened to you without one?
  7. I've got the JMC kit on my '66 and have 1" of travel at the slave. The engagement/disengagement is pretty close to the floor. I can see inside the slave that the piston could come out another 1/16" or so. I'm going to work on further bleeding at this point.
  8. Sorry to hyjack.....Does anyone with a JMC hydro. also have power brakes in a 65-66? I'm close to ordering what I need to install my t5 and I want to go hydro, but I also really want power brakes.
  9. Yes, I have the JMC master cylinder and power brakes. Because of the closeness of the factory holes for the brake and clutch pushrods, you must use a bellcrank booster. You must also use a booster that is compact enough to fit between the firewall and the shocktower. Check with NPD; they offer a bellcrank booster that will fit.

    I have a Scott Drake unit that I believe is not in production anymore. It fits the holes and the shocktower, but its fancy polished aluminum fluid reservoir doesn't clear the Maier Racing one-piece underhood brace I already had in place. I solved the problem by notching the brace, but it would have been smarter to get a late model MC with a more compact plastic reservoir.
  10. Thanks 180out.. I will give NPD a call tonight. Do you have any pics of your setup?
  11. Here's the only one I have on-line:


    It doesn't show much, except you might notice the booster/MC sits a couple inches higher than normal.
  12. They still have them, but they aren't with that MC though. THey have switched the MC on us twice. After yours, they had a plastic capped aluminum housing. Now they are back to just a plain old steel one.
  13. Hello,

    i did the conversion too. I use a booster from a 89 fox and a
    mc from wilwood. Not much space for the clutch slave cylinder
    but it works. I build the combination on the work bench to test the
    Here are alot of pictures from my work. Unfortunately in german.