I have a 1971 Opel GT, with an automatic transmission, that will not stop. Lately, if I am coming to a stop, as the car slows to about 10 MPH the engine starts to increase in RPM and the brakes will not work. It feels as though I can push the brake pedal further, but they start to release and the car will not stop, or she slowly accelerates. If I shift the transmission into neutral the engine revs but the brakes work. If I take my foot of the brakes before shifting into neutral then brake, the engine does not rev and the car stops normally.
Also, lately, the car has been hesitating when I try to start from a full stop. I have to gently pump the gas pedal to get her to go more smoothly. She also has stalled several times when starting from a full stop. Not sure if this is related to the problem of not stopping?
I suspect a vacuum leak, either in the hose going to the brake booster or the booster itself.
I was going to congratulate you when I had only read the title! I always like the look of those GTs and one that is reliable to boot!
I think that mc’s hypothesis sounds great.
On a different subject: If you want to sell your GT, they are highly coveted in Germany. My cousin’s husband works for a company that buys them in the US and imports them to Germany. He works on the cars to make them worth the big money they want.
Thanks for the suggestion. I checked the master cylinder and found that one of the two reservoirs is completely empty. Can I just add brake fluid or should the lines be flushed first? Could this be the problem? I did try starting the car with the brake pedal depressed. When the engine turned over, the pedal did move slightly further towards the floor.
Since the reservoir was empty you most likely have a leak and just replacing the fluid isn’t going to work. I suspect the leak is going into the vacuum system and may have to replace the booster, like Mcparadise stated. Check to see if the vacuum line going to the brake booster has oil residue in it.
After you add brake fluid you may need to bleed air out of the lines. Considering the age of this car perhaps a complete brake fluid replacement (flush) is not a bad idea. Find out where the fluid went first, though, and fix whatever is leaking.
Thanks for the suggestions. Will look into this over the weekend.
This is the car Don Adams drove in Get Smart, the spy spoof TV series. Yes, these cars are highly sought after. In view of the success of the remake of Get Smart, the movie, where the car is on display in “Control” offices, its popularity will be more so.
I think the car that Don Adams drove, at least for the show introduction, was a Sunbeam Tiger. That has a small V8 in it. Many years ago I had the 4 cylinder version of that, the Alpine.