KG-Virginia Posted March 15, 2017 Share Posted March 15, 2017 I have a 2013 1.6L EcoBoost Fusion with just over 45.5k miles. Recently it has started to exhibit an intermittent steering wheel jerking when I begin coasting. It only occurs after 30-60 minutes of highway speed driving, then occurs at almost any speed upon removal of my foot from the gas pedal. There is an associated rumbling noise in the front end when the steering wheel twitches/jerks. It sometimes occurs during acceleration and during braking, but mostly during coasting (no gas, and no brakes). Sometimes this results in a pull to one side or the other but it is not consistent -- sometimes no pull at all. The steering wheel will move between 5-15 degrees when this happens. I have taken it to the dealer and an independent repair shop -- neither can get it to do it while they test drive it (they don't drive it long enough under the conditions mentioned above) and no codes in the computer. This is not the typical out of balance or out of alignment problems -- very familiar with those symptoms. Sometimes it reminds me of the digital nature of ABS pulsing during heavy breaking. The frequency (cycles per second) of the twitching and rumbling does appear to be loosely tied to the speed -- lower speed, lower frequency; higher speed, higher frequency. I'd appreciate any feedback wrt similar symptoms 0 Quote Link to comment Share on other sites More sharing options...
eGuru Posted March 16, 2017 Share Posted March 16, 2017 When did you last service the front brakes? 0 Quote Link to comment Share on other sites More sharing options...
KG-Virginia Posted March 16, 2017 Author Share Posted March 16, 2017 12-15k miles ago -- Dealer turned the rotors. I get it inspected annually by the dealer and have routine maintenance done. They also flushed the brake lines at that time. Why would it only occur during coasting if it's a brake problem? Is there a feedback between the engine and the brakes ala a vacuum connection? E.g. coasting equals low vacuum? Seems like the highway time to get this to occur is decreasing -- now 20-40 minutes. I don't know any details about the steering and brake design and interconnection. I am an engineer with a good grasp of electronic controls, electrical power, hydraulics, and the fundamentals of mechanical rotating machinery. It's been cold here in VA for the past month and I have been using the floor heat regularly. Today on my drive back home, I turned down the floor heat and switched off traction control for a few minutes. The symptoms seemed to decrease -- unfortunately changing two variables at the same time can give false leads/conclusions. Where is the electronics module located? Could the floor heat be affecting it after 30+ minutes of thermal soak? 0 Quote Link to comment Share on other sites More sharing options...
eGuru Posted March 17, 2017 Share Posted March 17, 2017 I was suspecting that you are experiencing a sticky brake caliper and damaged or perhaps warped rotor. The caliper could be binding more after warming up during the drive. You could probably eliminate this as a cause by checking your rotor temperatures at the end of your drive to see if one is hotter than the others. 1 Quote Link to comment Share on other sites More sharing options...
KG-Virginia Posted March 19, 2017 Author Share Posted March 19, 2017 I'll check into this and let you know what the results is. Thanks. 0 Quote Link to comment Share on other sites More sharing options...
KG-Virginia Posted March 27, 2017 Author Share Posted March 27, 2017 After driving over 100 miles every day, I have check ed the rotor temps and didn't find anything significant. RF was a max of 30 deg F above the LF. Often they were the same or within 10 degrees of each other. The front rotors were always hotter than the rear by 15-50 degrees depending on driving conditions (stop and go vice extended periods of highway speeds). The symptoms seems to be changing as well. The jerking steering wheel is happening less often, but a rattling/clunking has increased. Still requires 30-40 minutes of driving to get it to happen. If I stop and put it in park, it seems like it resets. This is very annoying since I've taking it by my trusted mechanic after it has started and then it won't happen again. Today I crawled between the tire and fender to inspect the CV joint boots. The outer left (drivers side) boot had grease on it and I felt what seemed to be a small 1/4" tear. Going to take it into the shop on Thursday so they can inspect up on the lift and replace if necessary. I'll post the results after that. It still seems like the computer is playing a part in this and is controlling the transmission such that it pretty much only occurs when coasting/foot off the gas. As soon as I put my foot on the gas, the symptom goes away. But I don't have a schematic/block diagram/interconnection drawing, etc. so that's a shot in the dark. I'd love to understand the design better so I could try to make sense of this... In any case, thanks eGuru !!!! 1 Quote Link to comment Share on other sites More sharing options...
eGuru Posted March 27, 2017 Share Posted March 27, 2017 A defective bearing in the CV joint could definitely be the cause of the issue. Good that you found the ripped boot. See if you can hear any grinding sounds when making tight slow-speed left and right turns. Your observation that the symptom is only there when the loading changes from a 'forward' load to a 'reverse' coasting/deceleration load is consistent with how these things can fail. I doubt that this is a transmission issue. 1 Quote Link to comment Share on other sites More sharing options...
KG-Virginia Posted April 17, 2017 Author Share Posted April 17, 2017 CV Axle replacement on the drivers side solved the problem. I kept forgetting to login and post the final answer 1 Quote Link to comment Share on other sites More sharing options...
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