Unfortunately, you have a false sense of security if you believe this is the case. Your regular brakes continue to do their job, so it may seem like no big deal. If the wheel speed sensor becomes damaged or wears out, initially you probably won’t notice much difference in the way your car performs if your ABS light comes on unless you are driving on slippery pavement. That is why in general, it is unsafe to drive a vehicle with a broken wheel speed sensor. However, when it comes to wheel speed sensors, a minor-seeming glitch may turn into a major safety risk.
E46 M3 DIFFERENTIAL REBUILD RALEIGH NC DRIVERS
Drivers sometimes think that if a sensor is damaged or a warning light is on the dashboard, it can be resolved later down the road, as long as the vehicle doesn't break down.
In our opinion, from having repaired street and track cars, the best fixes for the subframe problem are:Ī) making the attachment points stronger by completeng the spot weldsī) reinforcing the sheet metal floor by adding more metal and spreading the load over a greater area (the tried and true solution done on the E36)Ĭ) using solid subframe mounts that will not twist under load (BMW went to solid mounts on the F10 M5 and F8X M3/M4)īelow are photos of subframe damage we have repaired in house.A safe assumption is that many drivers typically rank mechanical failures on their vehicles based on many variables, including cost to repair or replace. It also doesn't help if you already have cracks in the rear floor. It also makes chassis repairs more difficult and affects the rear crash structure of the chassis. This increased the rigidity but did not address the weak spot welds holding the subframe mounts to the body. Click here for more information on this kit.īMW's official fix for the E46 was to inject structural foam into the frame rails and the void between the trunk floors. This kit will save time when repairing the chassis, and is also strongly recommended as a preventative maintenance item. We also include instructions and new sheetmetal for reinforcing the top of the subframe mounts in the trunk floor, an often neglected location that also fails. This spreads the load over a wider and stronger area than before. Our Turner E46 rear subframe reinforcement kit thickens the sheetmetal over a greater area. This is where we have seen many failures of the chassis on low mileage street cars and race cars. The unfortunate side effect of this is that the load from the front of the subframe now gets transmitted to the left rear of the subframe. This cross member keeps the front mounting points from having problems by placing the bushing and the stud in double-sheer, thus reducing the twisting action on the sheet metal. A very similar issue preexisted on the E36 models and BMW fixed it by welding reinforcment plates on the floor.īMW tried to fix the issue during the design of the E46 by placing a cross member on the front two mounting points of the subframe. The issue is widespread on all 1999-2006 E46 sedan and coupe models (we have not seen any E46 convertibles with this issue). This constant loading and unloading weakens the sheet metal and causes it to fatigue and separate from the chassis (see images below). Worn rubber subframe mounts add fuel to the fire and promote further twisting. As the rear differential transmits the torsional load from the engine through the subframe, then into the chassis, the sheet metal flexes and twists and will break the welds with additional cracks forming through the sheet metal.
The attachment points where it gets bolted are spot welded to the sheet metal of the floor. The subframe is bolted to the chassis at four points under the trunk floor. As advanced and solid as the E46 feels it has a major weakness in the rear suspension: the subframe rips away from the chassis.