VIBRATION!!!
 

I could really use some help. I've read previous threads, road forced balanced a set of new tires, new wheel bearings and still... two harmonic vibrations. The car is basically mint with 48K miles. Absolutely 0 issues other than an extremely annoying vibration. I have a high frequency vibration starting around 30mph and continuing throughout. I have a heavier seat and lower steering wheel (mostly driver side) vibration starting at 50mph and continuing up through 80mph. Could the drive shaft rephasing help with both ?

Propshaft mount worn possibly.

Hi aaf8,

Assuming you are asking about your '95 X300, deterioration of the flexible coupling (aka Jurid, Giubo, Flex Disc, etc., part 5 in the diagram below) between the driveshaft and differential is a common cause of vibration. Likewise the center bearing (part 3) can allow speed-dependent vibration if the rubber surround allows the bearing to move out of its slight sideward orientation.

https://cimg5.ibsrv.net/gimg/www.jag...f122a8f624.png

Another thing to check is the transmission mount, or "rear engine mount," part 5):

https://cimg3.ibsrv.net/gimg/www.jag...a293cd44ad.png
A couple of other thoughts regarding your steering wheel vibration: check your steering rack mounting bolts, and also the front subframe/crossbeam rear pivot bushings, part 2 in the diagram below. When those bushings deteriorate they can allow the entire front end to wobble side to side:

https://cimg3.ibsrv.net/gimg/www.jag...14aa2d3110.png
Note that all of these items deteriorate with age regardless of mileage.

Cheers,

Don

Here is an old thread "Transmission Mount replacement advice needed please" where you can see some of the items mentioned above on my XJR were being replaced. I did not have the kind of vibration you described, but as my mechanic was then removing the manual gearbox for fixing a bad oil leak from the oil-plug O-ring, he had to remove the exhaust pipe, the propeller shaft, gearbox mount, the jurid, etc. to gain access, so the opportunity was taken to replace them as well. You can see that the old parts were already badly worn which would cause problems sometime down the road.

Q, what's a 'jurid'?

@Steve M Q, what's a 'jurid'?

See Don's post 3 above :)

"Jurid" is Part #5 in Don's first diagram. It is also called the propeller shaft coupling, usually made of flexible heavy duty rubber to withstand the force while absorbing the vibration. You can see that the coupling is held in place by many bolts. Many years ago, my Mercedes W124 vibrated strongly whilst in motion which grew with speed. Brought it to the workshop and found the coupling badly worn out, with one of the holding bolts missing. So it was like a wheel loosing balance as the propeller turned. These items do wear out with time (our X300s are close to 25 years old). AL NZ also has a long story about his propeller shaft since converting into manual.

Hi Steve,

Just to explain more fully, flexible couplings are typically made of hard rubber with metal sleeves to accept mounting bolts. They allow some angular misalignment of driveline components while reducing vibration.

Jurid Werke AG is a Germany-based manufacturer of brakes, flexible couplings and other automotive components and a long-time OEM to Jaguar, where the term Jurid came into use as a proprietary eponym for flexible couplings regardless of the manufacturer, similar to the common usages of the trademarks Kleenex and Xerox. For example, GKN also made flexible couplings for many Jaguars, but they're still referred to as Jurids. Jurid is now a division of Federal-Mogul.

Another common term for flexible couplings is Giubo, which is an Italian brand name created by contracting the words "giunto Boschi," or "Boschi joint" in English. Antonio Boschi was the inventor of the first flexible coupling. Giubo is often misspelled and mispronounced Guibo.

Cheers,

Don

Well, there you go, never too old to learn.
I've never heard of either term in 40 years of motoring.

Thanks to all for the advice.... Steve...awesome! I'll update as I go through this. Starting with the Jurid first.

Where can I find decent replacement bushings..prefer poly. I found the jurid coupler.

sorry for asking here, but i was searching the forum and this thread seemed relevant for a issue with my car. i have a vibration that feels like its coming from right rear wheel.

can't really feel it when accelerating but when i lift off throttle i can feel it. the local garage could not see or find any fault and the wheel bearings are new.

am i correct in thinking that jurid coupling is the culprit?

The Jurid coupling is on the propshaft, and hence is in the middle of the car. If you are feeling a vibration from one side, it is more likely one of the oft neglected universal joints in the driveshaft, which are supposed to be greased regularly.

If it feels like it is from the right rear wheel then it's unlikely the Jurid (which would feel more like the whole car vibrating). Failed Jurid is easy to spot by visual inspection (cracks) so the mechanic should have seen that if it was a problem.

Simple checks first - could be damaged wheel or tyre. Swap them around to check.

Also check for play in Driveshaft UJ (but I'd hope your mechanic looked at that also.

if i chose to simply buy a new jurid and a driveshaft u joint.. what kind of a task is it to install these bits? how many hours are we talking about for an average mechanic to do the job?

b1mcp makes a good point; if the vibration feels like it is coming from the right rear wheel, it might well be coming from the right rear wheel! Definitely start with a check of the wheel and tyre for damage, and the brake disc and calliper.