Accelerator linkage adjustment

[frederik]

So... I finally took the time to work on this. Last winter, my engine builder checked and replaced the diagonal pull rod. The one I had in the car was far too long (on the left in this picture, on the right is the new one):



This made the pedal feel much better, so I drove the car like this during the summer, but I still didn't have full throttle at the engine. So last week, I followed Ed's advice to the letter. Started at the pedal, adjusted it to the stop, and worked my way to the back. Now I easily get to full throttle and all play has been removed from the linkage, it feels awesome. Thanks Ed!

The only problem that remains is that I hear a creaky sound from the tunnel when moving the pedal all the way down. And there's a lot of play in horizontal and vertical direction on the rod in the tunnel. I suspect that the white plastic guides are worn or missing. In order to get to these, I assume the handbrake assembly needs to be removed?

[dummkopf]

Great thread! Mr EdMayo is the man!!! I was having the same problem. Time to break out the floor jack and jack stands...

[edmayo]

Proving that you must approach this in a logical manner, and you can't just jump around. To get the bushings you must remove the shift assembly, the hand brake and the third one one is under the rear tunnel cover. Glad you got it working Frederich!

[flat6guy]

Question. Are there specific measurements in the repair manual related to adjusting throttle? I know the 356 B/C manual has several specs to ensure proper carb drivability. The first third of the pedal travel on a 356 or 912 allow for smooth progression meant to make the car easier to drive in city traffic. Also the tip of the pedal is to be aprox 80m from the pedal board. Should that be the same for 911’s?

[frederik]

Proving that you must approach this in a logical manner, and you can't just jump around. To get the bushings you must remove the shift assembly, the hand brake and the third one one is under the rear tunnel cover. Glad you got it working Frederich!

Thanks! The tunnel cover is the easy one. I’m contemplating replacing my short shift kit by a standard shifter so that’s a good time to address the others.

Question: is there supposed to be a plastic bushing around the pin on the transmission? The bell crank there has a lot of play on my car, and that doesn’t seem right either. One by one, fixing all the little “shortcuts” made during restoration...

[edmayo]

Yes, absolutely the trans bellcrank should have plastic bushings so there is no slop.

[frederik]

Well I installed the bushing under the tunnel cover and it fixed the squeaking, and the pedal feels even better. It turned out I had bushings after all on the transmission bellcrank -- just with a little play. The new ones I ordered also had a bit of play so I left it like this.

All in all I'm very happy now. Especially adjusting the pedal to rest at the stop makes a huge difference in feel, heel and toe is easier, and being able to reach WOT feels like the engine gained at least 10 hp. Thanks Ed!

[edmayo]

To have all the controls, throttle, shift, clutch working correctly makes such a difference in the driving experience. Unfortunately if you don't know what is right you don't know what you're missing. I can pull a customer car in the shop and determine what it needs from that short drive. Glad yours worked out so well.

[Simonjjb]

Most cars I see don't have full throttle. There are three bellcranks that all must have good bushings as Mike said above. Start by removing the pedal floor board, often that bell crank gets bent over. You will need to study bellcrank leverage to understand how to do the adjustments. Bellcranks can only operate with a straight pull that makes max usage of the travel of the other arm on the crank. Look closely at the movement and you'll see what is needed.

The front bell crank on my car was bent just like you said it might be..now I will order my new linkage that I need - and then follow your great instructions !

[SFE]

Hi all,

I've found my bell crank bent like most of us.



Thanks to Mister edmayo I now know this bell crank should be 90°to centerline of the car but if so it touches the tunnel (yellow arrow).





All bushings are in place inside the tunnel.

I'm wondering if in fact my bracket is not bent ?



Do you think I can try to redress it ?