Driveshaft dynamic damper

[martinw]

Working on front brakes reminded me that I'd seen this earlier:-

O/S "dynamic damper" (Honda parts list description) seems to have destroyed itself - see pics, N/S one seems ok.

From reading elsewhere, seems this is caused by trapped moisture leading to corrosion on the shaft and that corrosion eventually causing possible snapped driveshaft ?

On mine, although you can't see it clearly in pics, there are signs of corrosion to the shaft inside the doughnut (and it seems like the diameter of the shaft is less there than the rest of the shaft - normal ?).

Anyway, my first thought was to cut this doughnut off, as it can't be acting as it should, the state its in. But, question is - if I do cut it off, is this going to cause vibration or other adverse effects ? (opinion seems divided as to whether these dampers actually do anything much)

Next - as I'm now worried that I could have a driveshaft that is already weakened, looking towards replacing it in near future (complete with CV joints both ends). Looking at replacements on Ebay, found a J&R item for a reasonable price, but no doughnut/damper on the shaft.

Anybody got experience of using these non-OEM shafts with no damper on their car (maybe in conjunction with the original shaft/damper on the other side). Any problems ?

Or, if I replace one side with no damper, do I also need to replace the other side with no damper ?

Also - do these non-OEM items generally come with the correct number of "teeth" on the ABS ring ? 

[dr_broon]

I used a j&r driveshaft when mine snapped, but the mechanic fitted it, so don't know about the damper. 

Quite a few people have used them over the years though, so hopefully someone can shed some light on it. 

[dr_broon]

Oh, and you can buy them direct from j&r from their website. 

[KiNK43]

I also use j and r shafts. No damper. I beat the crap out of them there great value for money and no balance issues

[martinw]

Thanks for the advice, will probably go for the J&R shafts when I get round to it (may not be far away, see below).

Decided to cut off the damper, mainly to see what damage the corrosion had caused to the shaft, but also to better understand the construction of these things.

First pic shows the damper after being cut off. There appears to be only one securing clamp on the outboard end and mine was still in place. So guessing the water gets in at the other end and corrosion starts? You can see where its been cut that there is a metal ring that is inside the rubber and goes all the way round the circumference. Decided to weigh the doughnut and it came to a surprising 10 ounces ! That's a fair bit if centrifugal force acting on the shaft ….. and (playing with the good one) this force is applied to quite a flexible rubber base where it meets with the shaft. 

Next pic is of the shaft after doughnut cut off and last pic of the shaft after wirebrushing.

Worrying amount of metal corroded away from the shaft where the doughnut was. So decided to measure it - the normal part of the uncorroded shaft was approx. 26mm dia (with paint). The narrowest part of the corroded area was only approx. 19mm ! That means the shaft has lost 27% of its dia (and strength) at that point, and the corrosion probably goes deeper.

No wonder these shafts can snap easily if corroded and put under stress.....

Luckily, my car has been (and will be) off the road until mechanically good and I,m not having to use it regularly. But if I was using it daily, I would be worried about driving it with a shaft in this state. And who knows if the one on the other side (that looks good) hasn't also corroded underneath the rubber ??

Guess most driveshafts snap when pulling from a standing start (?) and don't cause too much damage underneath or loss of control ? But say one let go at 60mph when you drop down a gear (or two) - you've got two broken ends of the shaft flailing around at high speed and maybe a disastrous loss of control ?

My own thoughts at the moment are that maybe there's a case for recommending that if your car still has the original dampers on the shafts, that you change the shafts to the non-damper (J&R type) asap..... 

[KiNK43]

Yeah it's madness isn't it. Hideous to imagine the shaft breaking as they so frequently do spinning round smashing things up 

[Dave]

bloody hell never knew the shafts were so thin! Must have a look at DD's sometime soon. Something I've never really bothered about but when you see that.....makes you think!

[dr_broon]

Crikey!   That's such a weak point now 

[martinw]

Update 

As moving onto the brakes on the other side, decided to have a look at driveshaft/doughnut on that side before ordering new driveshaft - in case I needed to order two.

As I already said doughnut on passenger side appeared good previously but wanted to have a really good look in case the corrosion had got in there too. Pulled the rubber back on the un-clamped inboard side of the doughnut and could feel a bit of flakiness to the paint but otherwise looked/felt good. Was just about to decide on cutting it open when noticed that when spinning the driveshaft back and forth, there was a distinct clunk from the inboard CV joint. As there was obvious slack in the joint and would need replacing anyway, decided to cut off the doughnut.

Pics below are what I found...….

Pretty self explanatory, but the pics of the doughnut cut open show that there is a difference in design/construction between the bad one on drivers side and the good one on passenger side (don't know if they are both original but suspect so). The good passenger doughnut is much more flexible when you try to turn it by hand coz the outer ring is attached to the inner sleeve by a series of rubber ribs whereas the drivers doughnut inner and outer parts are connected by a continuous rubber ring (less flexible). Don't know if this affects durability.

Anyway, what was significant to me was that on the edges of the pristine paint on the driveshaft under the good doughnut, the corrosion had already started (see bubbling paint). Give it some more time and you could have another weakened driveshaft with no exterior signs . Draw your own conclusions...….