OK, how do I get the master cylinder from a '91 RS into the firewall on my '82? I know the '82's were mechanical linkage. The '91 pedal assembly fit just right--but the '82 firewall has a crease where the '91 parts car doesn't, where I need to cut the hole. What's the best way to get that clutch working?

 

I swapped the hydraulic setup into my (late ) 83 - same thing.
I had to drill two smaller holes for the 'U' bolt, and slightly enlarge the existing hole that was used for the mechanical linkage. After I had installed it, about the sixth or seventh time I pressed tthe pedal, I heard a loud snap from the firewall area and found a crack had appeared radiating outward from the larger hole. Everything still worked fine afterward....

 

Thanks--at least I know it can be done. My '82 was originally an automatic so there's no hole there for the mechanical linkage. I might go to an aftermarket master cylinder if I have to, if somebody has a prefab solution to this, or make up my own, but my goal is to make it look as stock as possible.
If you could do yours over again would you make some sort of reinforcing plate to keep the firewall from cracking? I guess there's a lot of pressure there.

 

I swapped a hydraulic system into my 83 which came with linkage.... except my firewall didn't crack, because I didn't leave out any of the parts.

The thing that allows all the stress to be on the firewall, is when you don't put in the 2 brackets that go from the pedal pivot bolt, down to the U-bolt that holds the master cyl to the firewall. The brackets make the whole system work far better by helping keep the force from punching the cyl out of the FW (since otherwise, all that's holding it in is those 2 little nuts and their contact patch).

 

RB83L69--excellent advice, thanks. My pedal assembly is out of a '91 RS--I have the whole parts car--and I think there's just one brace from the right end of the pedal pivot bolt down to a point behind the gas pedal. Sounds like, from your experience, if I don't have a brace from the pivot to the clutch master cylinder I should make one.
Was yours originally an automatic? Mine was--and the FW looks different than the '91 parts car FW. Should I just go ahead and punch a hole for the cylinder, two more for the U bolt, and make a brace from the pivot bolt to the U bolt nuts? Thanks

 

No mine wasn't an auto; it's a 83 L69 (HO) Z28. Those only came with 5-speeds. Auto wasn't available until 84.

There should be 2 brackets. Maybe your parts car is already missing one. YOu could probably pick one up at the boneyard.

 

I probably would make a plate out of 1/8" steel if I were to do it again. I used all the stuff from my 84 Z28, reinforcing bars and all...I just attributed it to the difference in the firewall shape. I drove it for three years before the accident without problems

 

Alright, gentlemen, thanks, I think I know what to do: I'll use the '91 FW to make a cardboard template to locate the master cyl. hole--and no matter the contour of the metal there, I'll go ahead and make the hole. If the metal looks weak, like it might split with time, I'll make a 1/8" reinforcing plate and do it right, nothing rough. Then I'll do a bone yard search for that second bracket and if I don't come up with one I'll make one, from the pedal pivot bolt to the U bolt--on the left side because the right end of the bolt already has the bracket that goes to the floor behind the gas pedal. That should hold. I think I better take a good second look at all the parts on the floor of the parts car and make sure that second bracket isn't laying there--wouldn't be the first time.

 

OK--the clutch master cylinder from the '91 is made to mount on the flat '91 firewall; the integral flange locates the cylinder at the correct angle. The '82 firewall isn't flat; if I bolt the master cylinder right to it, flat, it doesn't point at the clutch pedal.
Did you guys make some kind of spacers to align the cylinder?

 

hey im a little late to this thread but i can help out! i just finished doing my hydro swap into my 82. with the brake master out as well as the dash and pedal assembly i had 2 holes on my fire wall both blocked off by steel plugs and seam sealer. the top plug is a flat section on the fire wall and a perfect angle for the clutch master. using a cardboard cutout of the clutchmaster flange i made the 2 holes for the U bolt and it slid right in place no need for spacers tho i did make a small reinforcment plate so my firewall wouldn't flex as much. if i get a chance ill snap a picture of what im talking about. ive been to busy to put the dashboard back in!

 

Hot69Z--Outstanding!! Thanks! Pictures would be a real plus. My friend who is stuck with this problem put the hole in the tranny tunnel using the reinforcement ring from the '91 parts car as a guide--no welding--and it looks bone stock original--but this clutch thing has had us stumped.
Maybe I didn't write the first installment of this string right; the difference in the firewalls is what really gets us--but these other guys have given us so much valuable info that we think we can make a solid swap that will last for years.
Did you use the braces they talk about from the pivot bolt to the U bolt? I'm gonna make them up. thanks.