Before I send these to my local machine shop to have Moogs put in can anyone tell me what the purpose of have these rubber bushings and a weird movable bushing at the other end would do? I would think that on Accel/decal they would pivot the tires so why not remove and use polyurethane? Anyone

 

Hi motofreak72,

Those suspension bushes help reduce the road noise, vibration and harshness (NVH) transmitted into the steering wheel and passenger compartment, so if you replace them with less-compliant polyurethane bushes, you shouldn't be surprised if the result is an increase in perceived NVH.

The "movable bushing" is the upper ball joint that allows the vertical link/steering knuckle to move within the constrained limits of the suspension geometry.

I've had very good performance from Moog parts in the past, but do your research on this forum - the original equipment bushings may have been made by Lemfoerder/Lemförder and you may find that they are available at prices similar to the aftermarket Moogs. Lots of sources have been reported in this forum.

Cheers,

Don

 

Don, Thanks for the description. Ive got the upper ball joint part that wasn't where I was confused. But, the mounting points one of which has a bushing the other side looks more like a pivoting point(where that finger is pointing in the pic). Just wasn't sure how this would effect the cars handling say I remove and replace with Polyurethane. I like the acronym though..(NVH) Noise, Vibration, Harshness Is that Jaguars or yours? I get it now though as far as why they are there so I may have to test out the feel when I remove them. I drive the car alot and am not afraid to get into the higher speeds and cornering. I am curious though if this will eliminate the sort of spongy/slight shiftyness of the rear when thrown into a corner. I would think the Air suspension should be enough to cover the NVH so to speak. If I don't like it Ill put it back with new Moog/Lem ball joints regardless.

 

NVH is a standard automotive engineering term and a critical parameter on a Jaguar. NVH is one key element that makes a Jag a Jag.

 

Modern cars, and Jaguars especially, are full of technology to combat NVH, but rubber suspension bushings are nothing new. Even on cars without air suspension, lots of components are isolated by bushings or mounts that incorporate rubber or other synthetic materials. These componenets include suspension control arms, subframe mounts, engine mounts, transmission mounts, differential mounts, anti-roll bars, crankshaft pulleys, coolant and power steering fluid reservoirs, radiators and other coolers, fuel pumps, air suspension compressors, and many other components. If you replaced all those bushings and mounts with solid, inflexible materials, you'd still have a car, but it would ride and sound like a tank.

As far as I know, Jaguars have featured these types of rubber bushes since at least the '40s. I know the 1948 XK engine had a rubber-bonded crankshaft damper made by Metalastik, Ltd., probably the best-known brand name of bushings that incorporate rubber bonded to metal. A German inventor, Fritz Schmidt, patented a number of designs for bushings with rubber vulcanized to metal, and he assigned his patents to Metalastik.

I know that's more than you ever wanted to know about rubber bushings, but suffice it to say, they are not new technology, and the specific bushing sizes and rubber compliance have been carefully chosen by the chassis engineers to provide the unique combination of comfort, handling and quiet that make Jaguars such wonderful cars to drive.

Cheers,

Don

 

Ok so I understand now why they are there. I mean its obvious there was a lot of R&D involved to get this right so why mess with what works. I am still curious though as to how bad the NVH would truly be if going that route and may just do it for giggles. I will however be looking to machine shop at least the ball joint portion of this and if it isn't to much trouble will than proceed to do the fronts as well. Ill let you know how it goes . Thank you for the knowledge and history lesson though I do love learning new things.

 

If I'm not mistaken, some members have replaced their bushings with polyurethane - search the forum for their reports. If you're looking for a firmer ride, you may actually prefer poly.

 

I'm one of the ones who went Poly, never again. The noise from the Poly bushes is awful. Never again. Squeaking & groaning, just awful...

 

Hi,
I have read conflicting stories.
Can you help.
Can I remove and replace just the ball joint from the upper control arm on my Jaguar XJ8 2004.
Or must I replace both the control arm and the BJ?
Previous threads suggest you could not buy the upper BJ separately .. Well you can so surely those suggestions are incorrect or outdated.
Please advise
Thanks
Please advise
Thanks
Robert

 

Robert,
Maybe somebody else will correct me, but from everything I've seen, you'll need to buy a whole upper control arm if the BJ is bad. Also, you'll need to remove the air strut in order to replace it.

 

Hi Robert,

It may be possible to press the old balljoints out and press new ones in, and it is likely possible to press the old fulcrum bushings out and new ones in, but these days the entire control arms with new balljoints and bushings are available at such low prices that I'm not sure it makes sense to go to all that effort.



Cheers,

Don

 

+1 on Don's comments. And I'll add that you can't replace the upper ball joint. Not because it's mechanically not possible, but because the ball joint is a unique size and is not sold stand alone. The control arms are cheap as a set on their own however as Don notes.

 

With respect to poly bushes, my friend replaced some on his Healey

and he was very surprised when they fell to bits!

 

Hi Don (and to Sean W)
Thank you both for your feedback and suggestions.
I have looked extensively online and found rockauto.com have the moog parts (front upper control arms for $87 each. Looks good.
Yes I found cheaper on eBay but for $20 more I'll go for the moog option as a previous thread mentioned them.
Also quicker delivery.
I shall also change the lower BJ's at the same time so now I hope no more knocks and bangs from under the hood anymore!
I will post again in due course
Best wishes
Robert

 

Sounds good Robert. I'm a fan of Moog parts. I think they might even be a tad better built than OEM Lemforder.

For others who want to buy the upper arms on the cheap, go your own way of course but I highly recommend avoiding DeutchePartsUSA. Their eBay rating is a miserable 98.9 (which is low for eBay), but their BBB rating is terrible as well. I have no skin in the game and rarely warn people away from anything but the savings don't appear to be worth the long term PIA of having to change them out again several months later.

 

I do have a question for the group. Motofreak posted the OEM pics and you'll note the crossbar on them. That was the same on my 05 SV8. Don's pic - there is no cross bar which is the same as my current 07 XK.
Is the cross bar necessary? Torsion related? Any ideas? Just curios is all.

 

That's a good question, Sean.

I just grabbed that photo from eBay, but I've seen the cross-bar type control arms to and had always wondered about them. Our '04 XJR does not have cross-bars and I don't see how the air springs/shocks could fit through arms that had them.

The Lemfoerder catalog shows both types but I don't have time to look up the applications right now. This is the page for the S-Type because inexplicably Lemfoerder shows the control arms for the S-Type and XF, but not for the XJ (this is apparently why so many sellers don't realize their S-Type arms will fit an XJ):



You can download the Lemfoerder catalog at the link below; the Jaguar parts are in the A-Me section:

Lemförder Lemfoerder Suspension Parts A-Me

Lemförder Lemfoerder Suspension Parts Mi-Z



P.S. Just had a minute to look at the parts diagram for the rears and that's where the control arms with the cross-bars go:


Cheers,

Don

 

Hi, I have ordeord the complete control arm and BJ, as you mentioned, I will need to remove the airstrut, I will not be doing this myself and will get my chaps at the garage to do this.
Do you have any tips or is this a fairly standard operation for a shocks n suspension garage.
Thanks
Robert

 

I replaced my upper control arms a few months back and it's pretty straightforward. Just undo the air line to bleed the pressure and then it's essentially just like removing a traditional strut assembly. If I can do it, then they should have no problem. If your garage doesn't do alignments, you'll make sure that gets done afterwards as well.

Also, I was in a bit of a time crunch when I replaced my UCAs, but I wish now that I'd just taken the extra time to pull the LCAs and inspect/replace the bushings. I'm not sure about your situation, but it might not be a bad idea to have them go through everything while it's in there. I replaced the tie rod ends, stabilizer bar end links, and lower BJs when I did the UCAs.

 

The LCAs can be inspected in situ. When I had mine checked on the previous X350, the technician used a pry-bar to see what movement there was. It wasn't a lot, but was enough to allow tow-out when in motion that started to wear out the tyre inner shoulders. So it's replace tyres or replace the bushes !