DMF's

[JohnD]

I belong to two or three caravanning forums and there have been several reports of premature clutch failures on Pug 307 and 407 HDI's, but never on Citroens. Given that the C5's has the same engine and transmission, how come the problem seems to be confined to Pugs? Any ideas?

[philipte]

The problem isn't confined to Pugs by any means, the DMF on my C5 failed prematurely. First sign was brief clutch slippage when drving along, which gradually got worse and worse. Still, by driving carefully I managed over 80,000 miles before the slip became too bad to live with. The car was regularly used to tow up to a ton.

When I saw the old components the friction plate was virtually unworn, but the DMF had excessive movement between the two halves, and the flywheel face showed definite signs of overheating.

Rumour has it that the DMF can disintegrate and exit via the bellhousing. I'm sure it could, but with a degree of mechanical sympathy it is possible to nurse things along whilst preparing for open wallet surgery.

[JohnD]

So maybe the DMF doesn't like towing. I believe Valeo have produced an alternative. It's a four piece kit which is much cheaper than a DMF replacement. The kit consists of a traditional rigid flywheel, a cover assembly, a high performance drive plate and release bearing. The vibration control function, originally performed by the Dual Mass Flywheel, is transferred to a long travel damper drive plate. In the event of needing a replacement, maybe this is the way to go.

[vince]

Being in the parts game, more and more people and garages are looking into the kits that convert back to solid flywheels as people simply cant see the reason why the design was ever changed and then being stumped with the higher cost on top....

Lets face it, how many flywheels have you ever had to change on all your old cars.......none? nope me neither....

[Gregg1100]

Hi Vince,
Same goes for PULL type clutches--what are they all about ?. Hit and miss whether you get the fork fingers in slots first time, and they get heavy action in a shortish period of time. The normal push clutch has been with us for years, easily aligned by a kit or an old first motion shaft
Like software on computers, newer is not usually better---too many bells and whistles/uneccessarily complicated.
Greg

[Gregg1100]

Sorry about double post---
Greg

EDIT - Citrojim: No worries Greg, deletion is easy

[Peter.N.]

The only failure you got with solid flywheels in the olden days was the starter gear ring wearing - before the days of pre engaged starters.

[np]

So maybe the DMF doesn't like towing.

I`ve just clocked 88k miles,32k since i`ve had it & re-mapped to 140 ish,the rest from new with my Dad.Both of us are caravaners.The car has towed to Italy 4 times & back,a few times to France,mega towing mileage from both of us.
Still have the original clutch & DMF.Although biting point is 3/4`s to the top of pedal now,but still going strong.

[AndersDK]

Anyone with a clue on WHY the DMF clutctches develops the problems ?

AFAI see it its down to the bonding being too soft, and then the clutch initially bounce because of the load and sets off slippage. Once started it wont stop until load removed, and will of course set off again on next load occurrence.
The whole thing gradually tend to set off on less & less loads because of the bad/damaged bondings which gradually allows for too much movement between the components.

Any other explanations ?

[bencowell]

My C5 HDI 110 had a powerbox fitted at about 25,000 miles. Clutch started slipping at 55k, replaced at 60k to be on the safe side.

The old friction material was like new and you could move the two halfs of the flywheel with your hand.

Clutch replaced with a Valeo solid flywheel replacement. Much much better.

The biting point is now constant (now got 95k on the clock), the clutch lighter and more progressive. It is easier to drive smoothly.

I'd recommend the Valeo solid replacement to everyone with the slightest hint of clutch problems.

Ben

[reblack68]

Our C5 has only done 60k and the clutch should last the life of the car. It annoys me greatly that not only am I going to have to replace the clutch but it's going to cost me several hundred pounds instead of the £100 it should cost.

It's not giving trouble yet but it will. I'm still convinced it's responsible for turning the C5 into a slug.

[ACTIVE8]

D.M.F...............I.E... Dual Mass Flywheel.

Seems it really should be......Develops More Faults.