Pedal Cluster model differences, HELP

zotman72 · 02:35 PM

I am in the midst of upgrading the brakes of my '74 911 racecar to '82 Euro SC specifications. This means OEM power brakes. Adding a brake booster and swapping out the MCs and pedal clusters. Several local (Denver) mechanics rolled their eyes when I talked with them about it and were not interested in the job. I would be not interested either except I am required to do it if I want to race my car in PCA stock class as E spec car this coming 2008 season.

Ok. Now the issue.

Take a look at these two clusters. Note the main shaft differences at point A. Apparently Porsche changed things on spacers and gas pedal lever activation shape on the later clusters. Should I swapped out the main rod from the '74 to the SC cluster? As it is now, I have two much room on the left side of the SC shaft (note pin hole visible). I do not want to swap out cables if at all possible, using the in place '74 clutch and accelerator cables. I already have modified the clutch cable attachment on the transmission end (e.g. no omega spring etc.) to work/function fine.

Note B location. There is an electrical switch of some sort on the '74. Huh? What is this for? As the '74 master cylinder does have a brake light switch,---what is NOT going to work if this switch is not operational? Do I need to rig this switch somehow on the SC cluster, as this would be a trick?

Thanks for any insight from those fellows who have been here before. This PCA scrutineer mandated task is such a crazy endeavor but then when does reason ever come into play when you want to go racing?

zotman72 · 01-21-2008, 06:11 PM

Ok I found the clear plastic spacer that came off the SC cluster, I thought it was a throwaway part but apparently it is not. I going through the SC cluster with a brass rebuild kit. SO the offset issue on A is settled. What about the actual clutch actuator bar, use the '74 one to match the '74 cable? I still have no idea about the '74 electric switch function still. Anybody?

1974carrera · 1974carrera's Garage

The switch at location B is for the brake lights. The presure switch on the '74 master cylinder is for the brake failure warning light.

zotman72 · 01-21-2008, 09:09 PM

Nuts, how in the sam hill am I to get brake lights working on the car. As the '74 electrical switch will not retrofit on the SC cluster easily. Does my SC master cylinder have a switch for this brake light activation role? Thanks Bob!

javadog · 01-22-2008, 04:02 AM

Well, if you are putting in the rest of the system (the booster, master cylinder, etc.) you won't have a problem. See the diagram below, from the Pelican catalog.

What I'd like to know is why you need to do this to be legal in your class this year. That's the part that mystifies me.

JR

javadog · 01-22-2008, 04:03 AM

zotman72 · 01-22-2008, 05:57 AM

I have an updated stock class car, going from '74 911S to Euro spec 911 SC. There was nobody to race against in PCA in the class of a '74 911S (formerly H) except for some lame water pumper types. There is plenty of competition in with the Euro SCs and next class below USA spec SCs. So accordingly, I have to make the '74 near identical to '82 Euro SC. Flares, wheels, engine, tranny, boosted brakes etc. Not cheap. Last season my updates did not pass PCA scrut muster and the boosted brakes are a mandated fix it before 2008 or no compete. Do not get me started....