In a manual transmission, the flywheel is a thick metal disc that provides mass for rotational inertia to help keep the engine balanced while it’s running. The torque converter performs this function by default on automatic transmission-equipped powertrains.
Like the flex plate on an automatic transmission equipped powertrain, the flywheel is bolted to the crankshaft in the center with six or eight bolts.
The clutch is bolted to the flywheel. The clutch disk splines to the transmission input shaft and the clutch cover (pressure plate) is bolted at its outer edges to the flywheel with six or eight bolts that are smaller than the bolts holding the flywheel to the crankshaft.
While most flywheels are typically made of durable cast iron, or steel, some are aluminum or Chromoly. If the clutch lining becomes contaminated or begins to slip a lot for any reason, hot spots can be created on the flywheel that will necessitate replacement or resurfacing the flywheel.
If the clutch lining becomes contaminated or begins to slip a lot for any reason, hot spots can be created on the flywheel that will necessitate replacement or resurfacing the flywheel.
– Richard McCuistian, ASE Certified Master Automobile Technician
Oil leakage from the rear main crankshaft seal is on the front side of the flywheel and away from the clutch lining, but the transmission front input shaft seal can leak and potentially damage it. Of course, if you have a leak as bad as all this, you’ve got bigger problems than hot spots on the flywheel!
Why You Should Resurface Your Flywheel
When hot spots form on the flywheel, the clutch can chatter, vibrate, and fail prematurely. In some cases, the crooked flywheel can also prevent the clutch from releasing. This can make the transmission unpredictable, so it’s not exactly an issue you can just ignore. Sooner or later, you’ll have to either replace or resurface the flywheel.
Replacing the entire flywheel assembly can be expensive, which is why some people turn to flywheel resurfacing instead. It offers a cost-effective solution that can help improve clutch performance, extend clutch life, and reduce noise and vibration.
How To Resurface a Flywheel
Resurfacing a flywheel by yourself can be difficult, mostly because you’ll need heavy equipment to do so. Here are two common ways of flywheel resurfacing:
Brake Lathe Machine
A brake lathe machine is a large tool used to correct a brake rotor’s uneven thickness, which is usually caused by uneven contact of the brake pad on the rotor surface or corrosion. It can also be used to resurface a flywheel, but this still depends on the size of the flywheels and the accessories of the brake lathe machine.
If you ask your fellow car owners about this, you’ll likely get mixed opinions. While some claim brake lathes are great for cutting flywheels, others believe they aren’t worth it. Brake lathes typically can’t cut hard spots on the flywheel, and you might find it hard to find an auto repair shop that still has a brake lathe machine.
Block Grinding Machine
Some auto repair shops have block grinding machines instead of a brake lathe. Also known as a flywheel grinder, this machine can recondition flywheels, clutch friction plates, pressure plates, and other circular pieces like discs, rings, and flanges. It grinds the surface of the flywheel using a type of stone.
Different machines will have different specifications, including the maximum grinding diameter. In most cases, however, using a block grinding machine will give you a better finish than a brake lathe.
When To Resurface Your Flywheel
If the clutch is worn or needs replacing, then you probably have to resurface or replace your flywheel as well. Here are other signs that you should get your flywheel resurfaced:
Excessive Runout
Excessive runout typically occurs due to poor resurfacing methods or when the flywheel has been exposed to excessive thermal overload. This causes the flywheel to wear faster due to its uneven surface.
Dishing
While it isn’t typically common with cast iron flywheels, dishing still occurs in steel flywheels, where a deep hole or pocket forms on the surface. These small cracks might not seem like a big deal at first, but they can get worse over time.
Hard Spots and Discoloration
Excessive clutch slippage can cause carbide hard spots to form on the flywheel. Because the surface becomes uneven, the new disc won’t fit properly, causing the clutch to slip and fail. You’ll need to resurface the flywheel to get rid of these spots.
Grooves
If you touch the flywheel and find grooves along its surface, then it’s best to either resurface the flywheel or replace it entirely. Grooves along the mating surface of the clutch disc mean the clutch has less contact area with the flywheel, causing it to slip or create hot spots.
Ring Gear Wear
A ring gear around the flywheel engages with the starter motor’s pinion, cranking the engine upon starting. If the ring gear around your flywheel is worn, then this means the flywheel’s weight is uneven. This slight imbalance can throw off the engine, preventing it from running smoothly.
Can You Resurface a Dual Mass Flywheel?
A dual mass flywheel, or DMF for short, consists of two flywheels that rotate independently, with one attached to the clutch while the other is attached to the engine. This design is meant to stop engine vibration from reaching the transmission and driveshaft.
DMFs come with dowel pins that can’t be machined or removed, which is why most manufacturers strongly advise against reconditioning DMFs. If your vehicle has a DMF, it’s better to replace it with a new one.
What To Consider When Replacing the Flywheel
If you’re lucky, you might get away with simply resurfacing the flywheel or replacing it on its own. In some cases, however, you might have to replace the clutch as well, especially if your vehicle has a DMF. When replacing a DMF, you typically have to replace the clutch and other components and consumables as well. This includes the throwout bearing, pressure plate, slave cylinder, clutch fluid, and transmission fluid.
How Much Does Flywheel Resurfacing Cost?
The exact price will depend on several factors, such as the auto repair shop you choose and your vehicle’s year, make, and model. On average, however, you can expect to spend anywhere from $20 to $50. In some cases, however, resurfacing won’t be an option, so you’ll need to replace the flywheel, which can cost anywhere from $40 to $1640.
Where to Get High-Quality Flywheels for Your Vehicle
As mentioned, the flywheel helps keep the engine balanced while it’s running. As such, it’s crucial to replace it once it is worn or damaged. Luckily, you don’t have to look far, as CarParts.com has high-quality flywheels.
Why waste time driving between stores when you can order the parts you need right off your mobile device or computer? Shop for OE-quality flywheels online, and get your order delivered straight to your doorstep with just a few clicks.
Our website has a built-in vehicle selector that lets you input your car’s year, make, and model to ensure that the part you ordered matches your ride’s specifications. And in case you have any questions, we have a friendly and helpful customer service team that offers round-the-clock support.
Order a replacement part from CarParts.com to get the best deals on flywheels today!
Keep Reading: Related Posts
Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.
