Technical Serious vibration

[RickDP]

Dear All,
Having just finished fitting a suspension raising kit to my 1988 4x4 I took it for a test drive to discover that it is now suffering serious vibration when the engine is under load. The vibration appears to be coming from the near side front. It is much much smoother when in the cruise or decelerating. At the same time as I fitted the suspension kit I also replaced the rubber boots and outer CV joint on that drive shaft. Can any one suggest what I might be the cause of the vibration? Thank you for reading; all suggestions welcomed.

 

[bugsymike]

Dear All,
Having just finished fitting a suspension raising kit to my 1988 4x4 I took it for a test drive to discover that it is now suffering serious vibration when the engine is under load. The vibration appears to be coming from the near side front. It is much much smoother when in the cruise or decelerating. At the same time as I fitted the suspension kit I also replaced the rubber boots and outer CV joint on that drive shaft. Can any one suggest what I might be the cause of the vibration? Thank you for reading; all suggestions welcomed.

Unless the raising kit is excessively high, meaning the drive shafts coming out of the gearbox are at too steep an angle when going down to the outer CV joints meaning they are working overtime all the time, then the most likely cause is a CV joint has become dislodged, a ball out or similar, it could even be the inner if it came out of it's joint to far when fitting the outer joint and boot.
If you jack the car up and slowly turn the road wheel you may see the drive shaft turning awkwardly or have excessive movement.

 

[RickDP]

Thank you, I’ll jack it up on Monday and take a look.

 

[Mike1alike]

Could be the engine mounts.

 

[Mike1alike]

Test the engine mounts by supporting with jack and wood the engine for the right side and the gearbox for the left side. Support, start the engine, feel if vibration is better.

 

[RickDP]

So I jacked the car up this morning and turned the L H wheel slowly to see what was happening. It looks like the rubber boot on the outer CV joint is rubbing against the head of the bolt that joins the lower arm to the anti roll bar. There are witness marks on the boot and splashes of CV grease all over the place. The rubbing looks to be caused by the excessive camber (6 degrees) resulting from the raised suspension legs. My plan of action is to modify the lower suspension mounting hole in the hub carrier into a bean so I can reduce the camber back to spec. Does this seem reasonable?

 

[bugsymike]

So I jacked the car up this morning and turned the L H wheel slowly to see what was happening. It looks like the rubber boot on the outer CV joint is rubbing against the head of the bolt that joins the lower arm to the anti roll bar. There are witness marks on the boot and splashes of CV grease all over the place. The rubbing looks to be caused by the excessive camber (6 degrees) resulting from the raised suspension legs. My plan of action is to modify the lower suspension mounting hole in the hub carrier into a bean so I can reduce the camber back to spec. Does this seem reasonable?

Correct me if I am wrong , but won't that pull the wheels out further putting extra strain on the drive shafts?
Years ago I saw a care with Hydrolastic suspension that had been pumped up really high and when he drove around a corner it forced the drive shaft to pull apart.
Is the lift kit supplied for your model exactly and if so can they advise as it may be to high and causing damage?

 

[RickDP]

Correct me if I am wrong , but won't that pull the wheels out further putting extra strain on the drive shafts?
Years ago I saw a care with Hydrolastic suspension that had been pumped up really high and when he drove around a corner it forced the drive shaft to pull apart.
Is the lift kit supplied for your model exactly and if so can they advise as it may be to high and causing damage?

Hmmm - I think you may be right. The kit is supposed to be designed specifically for the Panda Raid Series 1 4x4 Panda (5cm lift). I have to say that the supplier (Rialzi 4x4) have been rather lacking when it comes to customer support…..
I’ll have another play later in the week. If I can’t get it to work satisfactorily I think I’ll swap out the front struts for something a little more conservative.

 

[bugsymike]

Hmmm - I think you may be right. The kit is supposed to be designed specifically for the Panda Raid Series 1 4x4 Panda (5cm lift). I have to say that the supplier (Rialzi 4x4) have been rather lacking when it comes to customer support…..
I’ll have another play later in the week. If I can’t get it to work satisfactorily I think I’ll swap out the front struts for something a little more conservative.

Generally speaking if from the front you look at the drive shafts coming out of the gearbox to the road wheels, if the angle is much more than horizontal then every revolution the drive shaft makes the CV joint is working overtime, where as if it is horizontal the CV joint is just revolving without moving the bearings in their cups.
Five Centimeters doesn't seem very much, are you sure there is no other issue?
Are the top mounts offset, I don't know if that is likely on your model, but it can be on some?
Others on Forum may have done a similar conversion on their Panda 4x4s.
On old Series Land Rovers the front prop shaft universal joints always wore out much quicker than the rears as the front was very short so it had to work at a steeper angle where as the rear prop shaft was much longer to get to the back axle so it was a less steep angle. I have fitted many in the past.

 

[RickDP]

Generally speaking if from the front you look at the drive shafts coming out of the gearbox to the road wheels, if the angle is much more than horizontal then every revolution the drive shaft makes the CV joint is working overtime, where as if it is horizontal the CV joint is just revolving without moving the bearings in their cups.
Five Centimeters doesn't seem very much, are you sure there is no other issue?
Are the top mounts offset, I don't know if that is likely on your model, but it can be on some?
Others on Forum may have done a similar conversion on their Panda 4x4s.
On old Series Land Rovers the front prop shaft universal joints always wore out much quicker than the rears as the front was very short so it had to work at a steeper angle where as the rear prop shaft was much longer to get to the back axle so it was a less steep angle. I have fitted many in the past.

I’m not aware of any other issues (yet!). The top mounts are standard so no offset. The LH drive shaft on the Panda is very much shorter than the RH due to the position of the gearbox so the drive shaft is angled at quite an acute angle relative to the CV joint.

 

[bugsymike]

I’m not aware of any other issues (yet!). The top mounts are standard so no offset. The LH drive shaft on the Panda is very much shorter than the RH due to the position of the gearbox so the drive shaft is angled at quite an acute angle relative to the CV joint.

So not helping.
My concern is there is something else wrong, especially give you mention 6 degrees of camber, I assume positive?
So handling is going to be pretty weird.
If you stand at the front and look at the wheels, what does it look like, also if it is that far out then the wheel alignment is going to be miles out also.

 

[RickDP]

I’ve adjusted the tracking back to spec but it does indeed drive a bit wierd…..

 

[bugsymike]

I’ve adjusted the tracking back to spec but it does indeed drive a bit wierd…..

Definately excessive positive Camber.
Also look at the angle of the drive shafts, quite steep.
Something is seriously wrong with the modification.
Do you still have all the original parts?
I would be tempted to revert back to that or buy a kit that others on Forum with your model recommend.
Another option which may reduce acceleration pulling away, is to go with a higher profile tyre or larger wheels if applicable, that way the drive shaft set up is still original but you have a higher road stance.
I did this on a Skoda Scout which had the option of 17 inch wheels, but I kept to a fairly high profile tyre, performance wasn't an issue as it was a 2 litre 140hp diesel, but it handled well and sat nicely on the road. Incidentally the speedo then matched the GPS exactly.

 

[RickDP]

I do still have the original parts. My plan is to reassemble with the “slotted” hub carrier and lower profile cv boot and see how that works. If it is still problematical then I plan to buy some 30mm raised struts from a different supplier!

 

[kolza]

Have a read trough my post , some helpfull info there.

Panda (Classic) - My Sisley, Panda 4x4 - division north

As above this might be the cool print of the issue. It did rotate freely when manually spun at the assembly stage, but in theory at certain rpm and frequency it can wobble more as the tripod bearing races are at stepper angle. I'll get the front on stands and check from underneath at...

www.fiatforum.com

 

[RickDP]

Have a read trough my post , some helpfull info there.

Panda (Classic) - My Sisley, Panda 4x4 - division north

As above this might be the cool print of the issue. It did rotate freely when manually spun at the assembly stage, but in theory at certain rpm and frequency it can wobble more as the tripod bearing races are at stepper angle. I'll get the front on stands and check from underneath at...

www.fiatforum.com

Thank you Kolza, very interesting.

 

[RickDP]

Well I fitted my newly slotted hub carriers and new CV boot. Didn’t make an iota of difference ( other than correcting the excessive camber). As has been suggested I think the drive shaft must be catching on the gearbox tulip ( I measured the angle of the LH drive shaft - 18 degrees down from the horizontal). So in the interests of time and sanity I’ve decided to abandon the 50mm raised struts and go for 30mm instead. Thank you everyone for your comments.

 

[RickDP]

Help! Just when I thought I had the car sorted! On assembling my left hand side suspension this morning I found that the wheel did’nt rotate very easily. I removed the hub carrier assembly and both the hub bearing and the driveshaft rotate just fine. The problem seems to come when I bolt the hub carrier to the suspension strut. If I insert the lower ball joint into the suspension arm, rotate the hub carrier such that I can insert the lower of the two bolts (that attach the hub carrier to the suspension strut) the driveshaft still rotates easily. As I rotate the hub carrier to fit the upper bolt I can feel that the free play of the spider bearing sliding back in the gearbox “tulip” disappears and the drive shaft locks solid. It feels as though the driveshaft is too long and with the hub carrier in its proper position the driveshaft shaft is pressing into the gearbox internals. What am I doing wrong?? Any suggestion gratefully received.

 

[Mike1alike]

What you’re feeling is the inner CV tripod joint binding because of angle and plunge, which commonly happens during suspension reassembly.

The inner joint (the “tulip” and spider) is designed to slide in and out and only rotate freely within a certain working angle. When the hub carrier is rotated up to line up with the strut while the suspension is at full droop, the driveshaft angle becomes extreme. At that point the tripod rollers can bind inside the tulip, making the shaft feel locked solid.

That’s why it turns freely in one position and then suddenly feels tight or locked as you rotate the hub carrier.
It feels like the shaft is too long, but it isn’t.
Nothing is wrong with the gearbox or driveshaft. This is very common during assembly.
To avoid it:
support the hub carrier or lower arm with a jack
bring the suspension closer to normal ride height before tightening bolts
make sure the inner CV is fully seated in the gearbox.

Once everything is bolted up and the car is back on its wheels, the joint will sit in its normal operating range and rotate freely.

 

[bugsymike]

Unless of course something has fallen off the drive shaft joint and is jammed behind the shaft in the coupling, something I mentioned at #2.