Input sought for replacing dual mass flywheel
 

I have a 2004 Sonata 2.4 4-cyl that needs a clutch which I'll be replacing soon. I was surprised to learn it had a dual mass flywheel. I don't know if the flywheel is scored or not, but if it is, dual mass flywheels are expensive.

I see several clutch manufacturers who sell "solid mass flywheel" conversion kits to eliminate the dual mass flywheels.
I also see comments on the net that many OEMs do not recommend replacing dual mass flywheels with solid flywheels, but can't find any more details on why.

I'm not looking for a lightweight flywheel - I just want something that duplicates the stock behavior.

My question is: What have your experiences been when replacing dual mass flywheels with solid mass flywheels?
Has there been an increase in drivetrain vibrations?
Any other side effects?

Thanks,
Joe

RE: Input sought for replacing dual mass flywheel
 

Unless your flywheel is scored, I don't see a reason to replace it. It's just not normally done unless there's a compelling reason. Just take it to the machine shop and have it resurfaced if it needs it. Buy an OEM Valeo clutch kit on eBay for $100 includes shipping.

RE: Input sought for replacing dual mass flywheel
 

Thanks. I don't know if it's scored or not (we did teach two teenagers how to drive on it).

The longtime local machine shop says they can't resurface dual-mass flywheels - because they can't be correctly mounted.

I appreciate your input saying the dual-mass flywheels aren't normally replaced unless there's a compelling reason.

RE: Input sought for replacing dual mass flywheel
 

First of all, I was going to question whether the car truly had a dual-mass flywheel. In a another thread regarding Sonata clutch systems, I could not find any written reference to the dual-mass flywheel with either the EF or NF model Sonata's. This doesn't address your problem, but for anyone else who has read both threads, I have discovered I was wrong. Both single- and dual- mass flywheels were specified as far back as the 2000 model year Sonata. I still haven't substantiated whether the NF series uses the dual-mass clutch, but that issue for sure doesn't concern you.

Can you replace the dual-mass flywheel in your Sonata with a single-mass version to improve durability? I think you can and Hyundai may already offer the parts to do so. The graphic indicates the 2004 Sonata was offered with either a single- or dual-mass flywheel.

[IMG]local://upfiles/4972/D614D52572EC4AF197EF0F0DB576F1BA.gif[/IMG]

Seperate torque values are listed for the pressure plate bolts depending on which flywheel is present. It appears all other parts (disk, pressure plate, throwout bearing, etc) are the same, but this may not be true. You likely need to replace most if not all of those components anyway. In 2004, Hyundai issued a TSB regarding the conversion of Santa Fe's with the 2.4 liter I4 engine to single-mass clutch systems for warranty repair of failed dual-mass systems.

http://www.hmaservice.com/files/331/.../04-40-013.pdf

The TSB list the specific parts for the conversion. The replacement flywheel, clutch disc and pressure plate may work in your car, or even be the proper replacements to make such a conversion. You need to discuss this with your local Hyundai parts manager. Since the TSB provides Hyundai part numbers, you might even be able to reference these to parts manufactured by other OEM part suppliers.

Hyundai has issued TSBs to deal with dual-mass flywheel clutch systems in the Tiburon and Santa Fe, both models that are well known to have had premature dual-mass clutch failures prior to 2006. I cannot find a similar document for any year of the Sonata where the dual-mass was used. Either the clutches haven't been problematic in the Sonata or perhaps the dual-mass was a rare application in them.

Good luck.

RE: Input sought for replacing dual mass flywheel
 

Looks like you have to take it apart first and determine:

A. Is it a dual mass flywheel.

B. Is is scored.

Looks like you can get a new dual mass flywheel on eBay, but it's REAL expensive, like $700.
If you luck out and only have a solid flywheel, then of course it's a lot cheaper, or you can have it resurfaced. If it's not scored, you can sand it with sandpaper and a block of wood in a circular motion w/o removing the flywheel.

PS - The notion occured to me. Did you try to bleed the hydrolyic clutch system first? It's a real common problem. The clutch system gets hung up, and the clutch won't disengage. It happened to me on my Elantra, and I ordered a new clutch, dropped the trans, but much to my suprise, the clutch was fine, the hydrolyics were hung up. I bled the system, and it's been fine ever since. If you're not sure the clutch is burnt, then I would try to bleed it first, it could save you lots of time and money.