I refer the honourable members to my earlier post. At the dealers I worked for we were never allowed to jack under the DeDion either, but we had a commercial hi-lift jack to do the job properly. Without one of those I mostly jacked at the rear, or under the pinion crossmember, but in the real world there are times that the only way to get things done is jacking under the dedion, so it had to be, and with the ones I did that way I never had any problems. Problems are mostly caused, not by what you do, but the way you do it!
A Question About Jacking!
- Thread starter Jimbob-Squarepants
- Start date
Hmmm, unless a car is so badly damaged by corrosion that jacking from beneath the body either at the rear point or beneath the jacking points is not possible, then I can see no reason at all why jacking under the de dion tube would ever be necessary.
There is nothing beneath the car that cannot be removed successfully by jacking from the afore mentioned points. Sometimes the task may take a little longer and be a touch more difficult, but that is all.
Ron.
There is nothing beneath the car that cannot be removed successfully by jacking from the afore mentioned points. Sometimes the task may take a little longer and be a touch more difficult, but that is all.
Ron.
partviking
Member
I would phrase it thus, just cos you think you got away with it doesn't mean you have and doesn't mean others will as well.
The de-dion is 2 tubes one inside the other, the only way the inner one will lift (and it has to if you want to raise the car) if you jack the outer is by putting half the weight on the two oil seals and thin retaining steel washers at either end which are there to keep the oil in the centre and lubricate the expansion and contraction of the tube. Quite alot of weight on two small and delicate (IMHO) components. Add to this what I believe is an unatural strain on the Watts linkage and I think you could have problems.
Yes you can do it and yes it will lift the car but to assume you've done no long term damage to the oil seals that may eventually shorten their life Is perhaps looking through rose tinted specs. Fair enough I'm no technical expert and am expressing MY opinion but the engineers and technicians that created these wonderful cars are/were, would they really advise not to jack the de-dion in quite such strong terms if they were wrong??
harveyP6 said:
Unless you were ordered to jack the car from beneath the de dion tube by your boss.... :?
From a mechanical perspective, all can be achieved without resorting to such behavior.
Ron.
SydneyRoverP6B said:
I can't see how jacking it there can cause any more stress than it is under whilst driving. When you hit a pot hold its under a twisting force, that is one end of the inner tube is being forced down and the other end is being forced up words. This is a much more uneven force than you would exert when jacking. It's very substantial structure and if jacking there would cause damage then I would expect it to be unsafe to drive too.
richarduk said:
When Engineers (professionals with 4 years of full time University study completed) designed the rear suspension, the indivudual components and their material thickness was determined based upon the task that each would be required to meet, and together as a complete suspension system. If then for what ever reason a part, such as the de dion tube is subjected to a force that it has not been designed to withstand, such as jacking from beneath, then damage to that part may well result.
You could of coarse spread the force of jacking beneath the de dion over a much larger area by using suitable lengths of appropriate material, but that still does not mean that damage will not result.
It was never designed to withstand such a force, and there is no mechanical reason why you would ever need to.
Ron.
partviking
Member
I can't see how jacking it there can cause any more stress than it is under whilst driving.
Whilst the de-dion does actually move up and down think of it as a movement about a common axis, namely the end of the drive shaft where it bolts to the disc. So in effect each half of the de-dion is rotatating in an arc about this point. yes it is going up and down but it is also contracting and expanding. The forces are different because all the weight is on the road wheels and it is the wheel that is moving up and down, the tube is only maintaining it's position and allowing for the changes in track created by a fixed drive shaft. The de-dion is carrying no weight at all when in a fixed position other than it's own. All it's doing is stopping the two trailing arms moving to far out or too far in. It never was designed to take the weight of the car.
Whilst the de-dion does actually move up and down think of it as a movement about a common axis, namely the end of the drive shaft where it bolts to the disc. So in effect each half of the de-dion is rotatating in an arc about this point. yes it is going up and down but it is also contracting and expanding. The forces are different because all the weight is on the road wheels and it is the wheel that is moving up and down, the tube is only maintaining it's position and allowing for the changes in track created by a fixed drive shaft. The de-dion is carrying no weight at all when in a fixed position other than it's own. All it's doing is stopping the two trailing arms moving to far out or too far in. It never was designed to take the weight of the car.
Brian-Northampton
Administrator
Just moving away from the discussion on the De-Dion - almost wish I'd never asked 
My problem was to get the rear of the car in the air as well as the front, whilst only using two axel stands and keeping the car in the garage at the same time. Additionally my trolley jack would not fit under the rear trailing arms to jack under the coil/shocks.
I jacked up the car at the rear jacking point to get the wheels 4 inches off the ground. put a couple of fence post off cuts under each rear wheel.
Then I had room to jack up each rear wheel under the trailing arms, jacked each rear wheel up high enough to slide a ramp under each wheel.
Then jacked up the front at the front crossmember and put my big beefy 2 tonne each axle stands under each sill at the front jacking point with fence post cut offs between the stand and the sill.
This gave me 18 inches of clearance to work on the exhaust. kept the rear weight on the wheels for stability and only two axle stands. Rock Solid.
Not sure how I'd achieve the same thing with the front wheels on the ramps and axle stands at the rear without driving up the ramps because of the need to jack up the suspension - any ideas???
Thanks all for the discussion and help.
Cheers,
Brian.
My problem was to get the rear of the car in the air as well as the front, whilst only using two axel stands and keeping the car in the garage at the same time. Additionally my trolley jack would not fit under the rear trailing arms to jack under the coil/shocks.
I jacked up the car at the rear jacking point to get the wheels 4 inches off the ground. put a couple of fence post off cuts under each rear wheel.
Then I had room to jack up each rear wheel under the trailing arms, jacked each rear wheel up high enough to slide a ramp under each wheel.
Then jacked up the front at the front crossmember and put my big beefy 2 tonne each axle stands under each sill at the front jacking point with fence post cut offs between the stand and the sill.
This gave me 18 inches of clearance to work on the exhaust. kept the rear weight on the wheels for stability and only two axle stands. Rock Solid.
Not sure how I'd achieve the same thing with the front wheels on the ramps and axle stands at the rear without driving up the ramps because of the need to jack up the suspension - any ideas???
Thanks all for the discussion and help.
Cheers,
Brian.
As soon as they have finished building my garage, I will get mine off the ground by sitting it on four car ramps - bought another pair from ebay for £10. 8)
I was going to reverse it up onto the first pair, then jack the front up somehow (don't know how yet, but I am sure it won't be that difficult).
I was going to reverse it up onto the first pair, then jack the front up somehow (don't know how yet, but I am sure it won't be that difficult).
P6Rovers
New Member
EEEEK......Listen to "partviking".
I have restored 2 and two halves 2000 TCs and jacked many others all with a variety of rust from none to excessive. I have worked on Rover P6 for over 20 years.
Listen to "partviking" so you don't damage important bits or get hurt. The deDion tube looks attractive as a jacking point. Look at it as an important piece of precision SLIDING gear.
Eric (Canada)
I have restored 2 and two halves 2000 TCs and jacked many others all with a variety of rust from none to excessive. I have worked on Rover P6 for over 20 years.
Listen to "partviking" so you don't damage important bits or get hurt. The deDion tube looks attractive as a jacking point. Look at it as an important piece of precision SLIDING gear.
Eric (Canada)
MJP6B
Member
Quattro I agree 4 car ramps are the best bit of kit short of your own two/four poster lift.
My ramps are higher than standard (10 inches) and quite steep, so it is difficult to back up onto them without fouling exhaust/rear valance, so I drive forwards onto two ramps then jack up the rear and place the other two under the rear wheels. The car is stable and safe with enough working height underneath to do most jobs (except removal of gearbox when I jacked up higher resting all four wheels on additional cut lengths of old railway sleeper – this I found necessary to get the rear of the gearbox low enough so that bell housing could be turned slightly to clear tunnel making removal easier – bearing in mind that the whole engine /gearbox assembly has to be tilted 15-20 degrees).
Word of caution using this method of gearbox removal from P6: Make sure that your front engine mountings are in sound condition as they take quite a strain at angles they were not designed for
My ramps are higher than standard (10 inches) and quite steep, so it is difficult to back up onto them without fouling exhaust/rear valance, so I drive forwards onto two ramps then jack up the rear and place the other two under the rear wheels. The car is stable and safe with enough working height underneath to do most jobs (except removal of gearbox when I jacked up higher resting all four wheels on additional cut lengths of old railway sleeper – this I found necessary to get the rear of the gearbox low enough so that bell housing could be turned slightly to clear tunnel making removal easier – bearing in mind that the whole engine /gearbox assembly has to be tilted 15-20 degrees).
Word of caution using this method of gearbox removal from P6: Make sure that your front engine mountings are in sound condition as they take quite a strain at angles they were not designed for
Err, I stand corrected. Easy mistake to make I think.. "I need to jack it up, ah, that big girder on the suspension will do"...
Just looked at the hand book, page 137. It does say not to jack on the De-Dion but does say that pad at the back is for jacking, I thought it was only for the tow bar, guess not.
Easy mistake to make I think.. "I need to jack it up, ah, that big girder on the suspension will do"...Just looked at the hand book, page 137. It does say not to jack on the De-Dion but does say that pad at the back is for jacking, I thought it was only for the tow bar, guess not.
DaveHerns said:
I always managed with ramps at the front, and stands at the rear without any problems at all.
Make sure the fan blades are positioned across the rad, and don't drop the engine too far back as the O/S rocker cover can break the petrol reserve tap. V8 boxes come out a lot easier than 4 cyl ones, but are a bit heavier, although I always did them on my own, no problem. (Not sure whether I could now though.................. :roll: )
MJP6B
Member
If needs must Harvey, I`m sure you could !
Regarding supporting the gearbox on removal and refitting, I welded some scrap bits of angle iron into a cradle into which the gearbox sits at approx the right angle for removal/reassembly, it has a tube on the base which fits into the pad mount of my Bluepoint trolley jack (took about an hour to make up), it has been invaluable in the last ten years for clutch & gearbox jobs on the Land Rover and 3500S when a second pair of hands are not available.
In addition to the above post, when lowering the back of the engine, depending upon model, it is advisable to remove the top rad hose from the radiator as it can strain the neck and cause it to leak afterwards (just what you dont want when you think you almost there !) :shock: :cry:
Regarding supporting the gearbox on removal and refitting, I welded some scrap bits of angle iron into a cradle into which the gearbox sits at approx the right angle for removal/reassembly, it has a tube on the base which fits into the pad mount of my Bluepoint trolley jack (took about an hour to make up), it has been invaluable in the last ten years for clutch & gearbox jobs on the Land Rover and 3500S when a second pair of hands are not available.
In addition to the above post, when lowering the back of the engine, depending upon model, it is advisable to remove the top rad hose from the radiator as it can strain the neck and cause it to leak afterwards (just what you dont want when you think you almost there !) :shock: :cry:
