Throttle Coupler

Old 911, 912 cars have a poorly designed in-line coupler attached to the end of the throttle rod. It is rubber and deteriorates over time. Mine had sever cracks in it as you can see in one of the pictures below. The difficulty in repair comes when you discover that the coupler is frozen to the rod. I broke the throttle rod end trying to remove it.

To get at the parts rather than trying to fix this problem with the rod in the car, I removed the rod - starting at the gas pedal and working back - and discovered there are a couple (I found 2, the parts book shows a usage of 3) of plastic guides that keep the rod suspended in the tunnel. These have to be replaced - they are falling apart. They are not expensive - a few dollars each, but my car doesn't go all that well if you remove the throttle rod.

I am amazed at the number of plastic and rubber parts on this car. I guess after nearly 35 years it is not surprising to find they have not stood up that well.
031701-243 Here is the throttle bell crank when I started this project. As expected the original plastic bushings were completely gone. I ordered some brass replacements, but they are for a later design with smaller dimensions. Factory plastic were used instead of the brass ones.
031701-244 The bell crank after removal and cleanup. Next comes primer and paint.
031801-255 The rubber throttle coupler and connecting ball end fitting. The new rubber coupler is covered with a tube, such that if the rubber coupler were to break, the throttle would still work partially.
031801-256 Coupler showing that it is beginning to come apart. If it were to break, the car would be disabled. This is a good item to check on any old 900 series car.
032001-257 For the price of a new throttle rod, I rescued the old one by buying a set of taps and dies. The threads were cleaned up with the new tools.
032001-258 Here is the new rubber coupler encased in an open ended metal can. If the rubber were to break, the throttle would still work although not at 100%.
032201-260 The throttle bell cranks was cleaned up, repainted and the new plastic bushings pressed in the ends.
032201-261 The plastic guides keep the throttle rod from sagging in the tunnel. Any droop could cause some surging if the rod drooped while going over a bump. A bouncing throttle rod would effectively shorten the rod briefly, adding gas to the carburetors.
032401-262 Here is the completed project that you can contrast with the initial picture and the cracked coupler.
Last modified: Sun, 18 Mar 2001


Site Details. Disclaimer. Comments? Questions? Dave Hillman
Content attribted to others remains their property. Otherwise the text and images are licensed under a Creative Commons License.
Creative Commons License Valid XHTML 1.0 Transitional Valid CSS!