De Dion Tube greasing

arthuy

arthuy

Well-Known Member
Hi all,

I have been thinking for a while about this one and would be interested in a second opinion.

I have a 1977 2200tc. As some of you may know a few months ago I took the De Dion off to sort out the elbows.

Anyway I put it all back together and just before I took it off the road for an engine rebuild I heard a scrapping noise from the back which I am 100% sure means I didn't put in enough grease.

Reading the rover manuals it seems that the later cars were greased for life. The only way to re-grease them is to unbolt it all.

What I was thinking of doing was adding a grease nipple to the tube. has anyone done this and does it sound like a good idea?

Colin
 
I asked about refilling with grease a while ago but didn't get any feedback. In the end I thouroghly greased the tube on re-assembly and then added a little EP90 for good measure.

I think a grease nipple sounds like a very good idea. What about one at each end and maybe even look at positioning them so they inject directly onto the bearing surfaces rather than in the center.

BB
 
Manufacturers say 'sealed for life' but probably figure life isn't going to exceed 10 years.
I'm under the impression that the lubricant is for the smooth action of the 2 sliding tubes & that central topping up is the ideal option. Also, I've been told that grease isn't suitable for the de-dion's as it slides to the bottom after a while & gets pushed into a lump up one end, goes hard with cold weather or age (as you see on neglected wheel bearings..etc) & you end up with a dry & jerky (scraping?) tube. EP90 or engine oil (which is a bit thicker & clings to the surfaces a bit better) is the thing to use as it's free-flowing & slops around. Tricky to top up on the late tubes as you have to dismantle them to get any in but the earlier one's have the (central) filler plugs which makes life a lot easier though it takes ages to get any amount of oil in there due to the flush fit of the tubes.
Grease nipples may allow you to top-up the grease but the inner & outer tubes are so tight-fitting that you'd probably not get any grease through the nipple & fitting one in the first place would be nigh on impossible as you need a perfectly flush surface between the tubes so they slide smoothly & how would you manage that on the inside of the outer tube? If you fitted one at the end where the inner tube doesn't reach the grease would just sit there in a pile & not do anything. The lubricant needs to flow.
 
Unless the design changed at some point the de-dion tube (compared to the two i've seen on a 72 cars) bearing surface isn't the entire length of the tube, it's just at either end where two bushes made from a synthetic material are situated. There is some clearance between the inner and outer between the two ends.

I'd agree with you about the sealed for life and limited life span comment but I still think that a pair of grease nipples would be a good idea if you wanted to switch from oil to grease lubrication. A grease gun will excert enough pressure to force grease into the bearing and it doesn't have to finish flush, it could be arranged to finish below the bearing surface. Apart from reduced possibility of leakage topping up the tube with grease via the nipples would force any old congealed or contaminated grease out of the bearings and into the void beween the inner and outer tubes. (One of the advantages of universal joints with grease nipples on)

Anyway all this talk of nipples is getting me a bit hot under the collar, I'll have to go out in the garage for a play with my own!
 
Well! I've had my '75 2.2's sealed tube apart & I seem to remember the tubes being the same diameter all the way down & when I topped up my '69 2000's tube with the filler plug there didn't seem to be a gap & the oil took AGES to drain down into the tube & if the oil was finding it difficult then grease would probably just squirt out around the nipple rather than through it (Ooer Missus!). Maybe I'm wrong about the diameters but more than one mechanic has told me grease isn't a good substitute for oil for the reasons I stated.
After all, Rover recommended oil.
Has anyone out there actually tried nipples before?
 
Speaking to a local mechanic who is used to working on P6s, he reccomended Vaseline rather than grease for the tube. Not sure I agree, but he said grease attacks the synthetic bushes. I would have thought that Vaseline would do the same, and attack the rubber gaiter, and not offer the same amount of lubrication. Any thoughts?
 
Grease does rot rubber, not sure about Vaseline but it still won't flow.
I've just bought a P4 110 (Where will it end?...... :D Actually I hope it doesn't as I'm dead chuffed & can't wait to pick her up) & the kingpins on the P4's have to be lubricated with oil only as grease is death to them. The P6's De-dion tube's recommended lubricant is also oil.
 
I think your mechanic is making it up as he goes along. I feel sure that the synthetic bushes would have been made from a material impervious to attack from oils or greases since that is the recommended lubricant. There are oil seals at the end of the tubes and the gaiter is not really designed to retain the oil it's there to stop the elememts getting to the exposed end of the inner tube. (

Pulled the two halves of my spare de-dion tube apart to have a look today and I was right about them not being the same diameter all the way along. ~(yes i am a pedant!)

01010005.JPG


The inner tube measures 65mm for approx 6" at either end and the centre section (painted black) measures 64mm.

01010006.JPG


Inside the outer tube the synthetic bearing at each end (yellow) gives a running fit to the ends of the inner tube. Between the synthetic bearings the diameter is approx 69mm giving around 5mm clearance between the two tubes.

If I was going to add grease nipples I would fit them so that they squirt grease directly through the yellow bearing. Having looked at it though I don't think it's worth the hassle (For one the gaiter would get in the way at that end). If your rebuilding it fill it with oil on the bench where it's easy to get to. I've had a few car with de-dion tubes that looked like boat anchors on the outside but didn't leak and were still full of clean oil on the inside when dismantled.

01010007.JPG


This last picture might be useful if you're dismantling. It's the retaining clip that doesn't actually stop the two tubes being seperated but does score the bearing surface and oil seal if you don't take it off first! I've no idea why they bothered with it.
 
BB,

Sounds fair enough.

That tube you stripped was an oil filled one, are grease filled ones the same size only with/without filler plug?

What I am thinking is either to getting an outer tube with the plug and making up an adaptor for the grease gun. What about putting grease in a tube designed for oil would that be a bad move?

It is P6 week in my house will lots of concurrent activity going on, I have for the first time sent some items away to be refurbished. Mainly to let me get on with putting the enigine together and back in the car in an attempt to do some rallies this year.

Since I can't much whilst the paint on the engine is drying I decided to make a start on the electric window conversion I have been taking about for ages. I am glad to report it has been a success, I just need to figure out how to fit the switches. where I want them. Did you go for electric windows in the estate bennet?

Colin
 
Are you using standard P6 electric windows ? or a custom conversion ?

I used 216 rear mechanisims on mine, and standard rover rocker switches in the speaker grill area of the center console.

Richard
 
Colin,
the NADA models had electric windows and I believe that their switches were mounted on the centre console. (I'm looking for a photo' as I type this!)
Ian Wilson has a lot of NADA stuff for sale why not give him a call?
Regards, John.
 
Thanks John/Richard,

My Windows are a custom job. I got a set of knackered sd1 doors so I have a complete set of switches, motors, relays, central locking motors and wiring. I am quite please because this was cheaper than buying the component parts.

I had to modify the existing p6 regulator, cut and welded the sd1 bits up to make a bracket for the motor. I have plans for the switches, I just need to work out the fine detail. I don't want non standard items on view on my car so you wont be able to tell at a glance. I promise to draft up a piece for the p6 news and some pictures.

Colin
 
I can't imagine that there is any difference between the grease filled and oil filled tubes but perhaps someone with more experience like Ian could confirm.

No electric windows for me Colin, I'm a budding luddite! Actually I do find hand wound windows are a pain as you can't wind them down on frosty mornings to see where your going so i'd be very interested to read about your conversion.
 
Back to the De dion tubes. Mine is a grease filled one. I cant see any oil seals on it, apart from the furry thing at the gaiter end. no sign of any rubber seals. I have a spare lying about now (since my suspension collapsed) also grease filled and no sign of any rubber seals. Are they both missing something?

I dont think I would bother adding grease nipples etc, as its not too bad a job to re grease every few years.
 
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