Manual cars are still around thanks to enthusiasts and those who appreciate the simplicity of a flywheel/friction plate combo. The way these key power transmission components are designed makes them prone to wear.
Diagnosing BMW clutch issues is something many manual car owners will have to do at one point as it’s not a matter of if, but when your clutch will wear out. If you suspect that your clutch is on its way out, there are a few things you can try to establish the diagnosis.
The Inner Workings of a Clutch
The average car drivetrain can be described as perfectly organized and synchronized chaos. Engineers who designed and built your BMW have figured out the optimal way of harnessing the violent, raw power of your engine, and how to transfer it to the wheels.
A clutch plays a critical role in this process as it controls when your gearbox is getting power, and how much. The way manual clutches work is pretty simple. The engine’s crankshaft is mated to a flywheel that spins as fast as the crankshaft is rotating.
Facing the flywheel from the other side is a friction disc coated with a special friction compound. This disc is held in place by a pressure plate. When you press the clutch pedal, the diaphragm spring forces the friction disc away from the flywheel, thus separating the transmission from the engine.
Once the friction disc is no longer touching the flywheel, you can change gears. With a new gear selected, you slowly take your foot off the clutch, which makes the friction disc engage the flywheel once again. At this point, the power is once again being transferred through the gearbox and further down the rest of the drivetrain.
What Causes BMW Clutch Issues?
Driving a manual car means that you’ll be engaging and disengaging the clutch dozens if not hundreds of times per day. This causes wear on the friction plate, but also the diaphragm spring and every other part of the clutch. That being said, we have to emphasize that clutch wear is normal. Clutch is a wear item. However, the rate of wear is almost always down to the person operating the clutch.
The moment when you engage or disengage the clutch is critical. We all know what happens when you dump the clutch, but we also know that riding the clutch causes excessive friction disc wear. The optimal way to use the clutch is to feather it just enough that you get a smooth gear engagement. Anything beyond that is riding the clutch.
An average clutch should last around 100,000 miles or so. However, these figures are calculated with average drivers in mind. Drivers who are new to driving a manual gearbox will often wear out the clutch much sooner, especially if it’s a used car with an already worn-in clutch. The reason why clutches rarely last a long time in the hands of newbies is that they have a tendency to ride the clutch.
Anyway, a worn-out clutch is nothing out of the ordinary. The key is recognizing those early signs that a clutch is nearing the end of its life. That way you’ll have plenty of time to organize a clutch swap, all while minimizing the chances of being left on the side of the road somewhere. Here’s how to diagnose a faulty clutch on your BMW.
Diagnosing BMW Clutch Issues — How Do I Know When My Clutch Needs to be Replaced?
Although the basic principle of clutch operation isn’t all too complicated, there are still plenty of moving parts to make the troubleshooting process a little tricky. That is unless you know what to look for.
There are several components that can fail, all of which fall under “clutch issues”. These include the following:
- Friction disc failure
- Pressure plate failure
- Hydraulics, mechanical linkage failure
- Dual Mass Flywheel Failure
Most of the problems you’ll experience with your car’s clutch will be in relation to these components. Let’s start from the top.
Friction Disc Failure
One of the most common clutch failure points is the friction disc. No matter how you drive, the friction material wears out at a steady pace. Then, it begins to slip.
Worn Out Friction Disc
More often than not, your clutch will begin to slip gradually. You may not even notice it at first until you get on a highway.
The clutch will most likely begin to slip when you reach higher RPM in higher gears. Interestingly enough, it will generally work just fine in 1st, 2nd, and 3rd gear. That being said your clutch slipping in the higher gear should be taken as a serious warning sign. It’s highly recommended that you start planning a clutch replacement if you experience these symptoms while driving.
Pressure Plate Failure
The pressure plate, along with the diaphragm, is also prone to wear. The constant pressing and depressing of the friction disc to the flywheel leaves a mark. Symptoms of a failing pressure are numerous and include the following:
- Clutch slipping
- Difficulty engaging or disengaging the clutch
- Spongy pedal feel
- Noise right when the clutch bites
- Gears slipping
All of these symptoms may or may not coincide with a worn-out friction disc or any of the other clutch symptoms we’re about to discuss.
Because of that, if you’re replacing any of the clutch components on your BMW, it’s highly recommended that you replace the entire clutch assembly at once. Even if only your friction disc is worn, but everything else looks decent enough, you can’t know how long the other components will last.
Hydraulics Failure
Although most clutch issues can be traced to items that wear out, like the ones we’ve mentioned above, there are outliers. Most modern clutch systems feature a hydraulic system that actuates the pressure plate via a set of hydraulic cylinders. The master cylinder drives the slave cylinder, which then applies pressure to the diaphragm.
If any of these cylinders fails, you can experience a sudden loss of clutch control. Additionally, any leaks result from a clutch cylinder failure, or hydraulic line failure can lead to friction disc contamination. At that point, you’re dealing with compounding issues.
Mechanical Linkage Failure
Long before hydraulic clutches became the norm, most cars ran mechanical linkages. You might find these in older BMWs. Mechanical clutch linkage can fail suddenly, or gradually.
If you suddenly lose the ability to control the clutch, you are most likely dealing with a broken clutch cable. Unfortunately, this is the type of failure that will leave you stranded on the side of the road.
On the other hand, if you gradually begin to notice difficulties while shifting gears, there is a good chance that your clutch cable only needs to be adjusted.
Dual Mass Flywheel (DMF) Failure
Modern BMWs produced from 1991 and later, such as the popular E46 3-Series, feature a dual-mass flywheel. The idea behind a DMF is to dampen the uneven vibrations produced as each cylinder completes its power stroke. To achieve the dampening effect, DMFs feature two independently moving pieces that feature a set of springs between them. It’s those springs that neutralize any excess vibrations. However, they are also what makes a DMF prone to failure.
Once the springs fail, the two independent masses will gain some play. This unwanted and often lateral movement often causes all kinds of weird vibrations and knocking sounds when the car is driven.
Just like with a friction disc, DMF failure isn’t a matter of if, but when. Once your DMF goes
What Happens If You Keep Driving with a Bad Clutch?
Driving around with a clutch that’s showing early signs of failure is not recommended. Yet, this is exactly what many people do, thinking that there’s nothing wrong with driving their cars until the clutch no longer works. It’s not that simple.
A clutch that is making it difficult for you to change gears can lead to transmission damage. By forcing the gears while your clutch isn’t disengaging properly, you’re putting a lot of strain on the synchros. Losing synchros implies a gearbox rebuild, which is much more expensive than replacing your clutch.
Of course, even if your synchros survive the torture, you’re risking being stranded on the side of the road somewhere.
BMW Clutch Kits — Which One to Get?
Replacement clutches are a hot topic in the BMW community. Opinions are generally divided between OEM clutch kits and aftermarket kits that allow for more performance should you need it.
If you’re only looking to get your car back on the road and make it dependable again, we strongly suggest sticking to OEM or Genuine BMW clutches. You can find both in our catalog by selecting your car’s year, make and model from the dropdown menu. We’ll touch upon performance and competition clutches another time, as that’s a whole different subject.
