Hydraulic clutch in 73 pickup?...what are the options?

[slammed48]

What are the options for putting a hydraulic clutch in a 73-80 pickup?...

Is there any option to avoid hacking on the firewall to put a master cylinder there?

[greg64]

Hi slammed. I have a 77 truck that I retrofitted a hydraulic clutch into. It turned out to be fairly easy, but did involve some fabrication. I used the clutch cylinders from a 93 chevy truck (what I happened to find at the yard). But I'm going to replace those with the 91 cylinders that I used on my Suburban, because they were easier to connect hydraulic lines to.

I didn't hack up my firewall, I just drilled a 1" or so hole in it. I could take some pictures if you really want to see how it was done.

[hatzie]

I have an 87 or 88 R30 pedal set, clutch master, and Hydroboost in my 1976 to fit the NV4500 and 6.5L diesel.
I agree you don't have to hack up the firewall. The holes are not large and even the master cylinder would be hidden at least partly by a Vacuum booster can. I added small 16ga sheet metal plates barely larger than the clutch master flange on the inside and outside of the firewall. I put those plates on to add support to the firewall sheet metal. I probably could've used the clutch master from the 1998 T400 K30 transmission donor.
If you're worried, and the donor cab is spent, you may be able to get a section of the later model firewall. Or. Tape a sheet of heavy paper over the brake master and clutch master holes and mark the hole locations from inside the cab...
The 85-86 CK or 87-91 RV trucks have hydraulic clutches stock.

Make sure to get the pedals from the correct flavor of brake assist Vacuum or Hydroboost. Be sure to get the booster pushrod as well. The pushrod pins are in different locations on the pedals depending on booster and brake options. I cheated a bit and got the pedals, brake booster, pushrod, and clutch master from one R30 truck.