Hi, guys. I've been tracking down various issues on my 04 XJ8 over the past couple months and have a hopefully easy question. My car is leaving a spot of blackish "oil" by the right front wheel. I say "oil" because it seems less viscous than engine oil, practically water like, but it will not evaporate like coolant. It has been dripping about one dime sized drop per day for the past week or so. It is dripping down on the floor from the lower forward control arm (where the circular bulge is). I have read through various threads and it seems that there is some debate about whether the control arm bushings are solid rubber / nylon or fluid filled (hydrabushes). As I cannot find any oil leak above this, I believe it is the bushing that is leaking. First, can anyone confirm that this is indeed a hydrabush and that it can theoretically be the source of the leak? Would the fluid be thin like I'm describing?

Second, assuming I decide to replace the bushing, it looks like it's probably just as cheap to replace the entire control arm as it is to source the bushing and have it pressed in. I have shopped around for new aftermarket control arms, and I see that there are numerous suppliers in the $115 to $150 range, such as SNG Barratt, Febi Bilstein, etc. It's hard to tell from the pictures, but it looks like these parts probably do not have hydrabushes, as they do not appear sealed. Is there any noticeable difference in bushings across these parts? I suppose I would like the bushing that gives the softest ride, as I do not drive aggressively at all.

Finally, is there any compelling reason to do these in pairs or do other parts while I'm in there? I don't see any reason why it would matter much. Given it's an 04, I probably am not going to totally refresh the front end proactively, as it rides great the way it is. What's the next most likely issue in that part of the suspension, not counting the air suspension parts?

Thanks!

 

Looks like something above may be leaking down on the rear side.

 

The front trunnion bush is a hydrabush according to the Technical Notes for 04/05 cars. These are replaceable separately from the arm, and I had mine replaced on the first X350 I owned from 2010 - 2016. Provided the mandrels and a press are available, it is a reasonably easy swap-out. Mine were done by a specialist Jaguar shop. Of course it is a toss-up between the additional labour to swap-out the bushes, and just swapping out the whole arm which costs more than the bush. Apart from the leak you are seeing, the failure of this bush causes tow-out when the car is in motion causing wear on the inside shoulder of the front tyres. an alignment check may not show this tow out because the vehicle is not moving.

This is the front bush: -

https://www.jaguarspares-northeast.c...or-jaguar-x350

 

Replacement parts are not very expensive.
Would replacing them change your alignment?
I would think not, as there is not an adjustment to change much here.
Just helps to stabilize things from shifting more or less???

 

I would re-align after replacing parts just to have everything centered; for another $50 its worth it and could save you some tire life.

However, i just replaced all control arms and bushings on my 05 about a year ago. The wishbone arms definitely didn't have fluid in the bushings, that has to be something else dripping onto it. I wouldn't change the wishbone/bushing unless you know for a fact they are bad.

The comments above are spot on about identifying the wear in the wishbone bushings. A laser alignment wont tell you. But you can see it if you watch someone else drive the jag slowly forward with the wheel turned and hitting the brakes, you'll see the entire rim and tire jump/flex backwards. I think it also happens under hard acceleration, but that is harder to see 3rd person POV.

 

The engine mounts contain hydraulic fluid - your right mount could be cracked and leaking fluid down onto your control arm bush.

 

Believe your right on target with the motor mount leaking.

 

I will read up on the right engine mount and see if that could be it.

anybody know how much fluid is really in play? It seems like there’s not enough volume in either a hydrabush or engine mount to really leak for that long.

I’m also going to try some UV dye in the coolant to make sure it’s not some small leak from there somehow dripping down.

thanks for the tips!

 

There can't be much in there, they (the motor mounts) are not all that big.

 

Did all new poly bushings on mine, front and rear for £35!
hardness was 85A I think
drives like a dream now!
not too harsh and very precise