I finally got around to installing the X308 mono strut with replaced Powerflex street bushings. In addition, I replaced the outer A arm bushings as well.


Mono tube. This completely eliminated the hard 3-4 shift from the transmission up through the steering column. I applied primer over the existing finish after cleaning it. Just for fun.




Painted with matte finish. Powerflex street bushing installed. The middle is open to show the two piece nature of these bushings. These press in without special tools which is nice.




I swear the car sits a bit higher now. The rear end definitely doesn't move as much and you can now feel the give in the front suspension with direct input from the rear. Now I need to add a rear sway bar!



It was a pain with hand tools and no lift. The rear mounting points for the mono tube were a bit too narrow and it spread the bracket out and distorted the bolt angle as the backside of the bracket had a welded nut.

Other than that the rear bushings came out by hack sawing to relieve tension and then chiseling out with a mallet.

The car feels SOOOOOOO much better. No hard hits in the rear (all of my bushing looked excellent btw, 108K+ SoCal car). It feels like the tires are so much more firmly planted and the shock is finally able to do it's job without interference. It is not harsh in any way at all. In fact, over the stock used bushings, the car feels much smoother and no harshness or hits over expansion joints, etc.

 

Thanks for the write-up! I plan to cut the old bushings out as well, and get mono-strut powder coated.

Which bushings did you get for the monostrut?

Can you provide the part# and URL?

.

 

One of the downsides of poly bushings is that they can squeak. I wonder if that is a non-issue with these since they shouldn't be flexing or rotating too much?

Found them....

Part Number: PFR27-209x4

PowerflexUSA - XJ6 - X300 - X308 (94 - 02)

Jaguar XJ6, X300 & X308 (94 - 02) Rear Panhard Rod Bushing

 

Told ya' so.

I predict a run on ebay for these parts.

Best bet is to find a X308 XJR and buy both the
monostrut and all the arb pieces together including
the mount plate.

The lower control arm already has the ARB link tab
welded on.

 

Good thing they are still cheap and plentiful, think they were on the XK as well.

I got mine for $15 on eBay and see them all the time for $40-50ish.



.

 

I paid closer to $50 something shipped.There is no squeaking at all, that's a standard with Powerflex bushings. I am a dealer and can offer 1/2 off shipping for what it's worth.

 

Sounds interesting. Sure wish I knew what you guys are talking about. What advantage are you getting over the standard X300 rear suspension?

Thanks guys

 

See the following thread for more info:

https://www.jaguarforums.com/forum/x...t-x300-143384/

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I just ordered my monostrut... found on on eBay for about $25 shipped.

From what I've been reading it seems like a simple drop of the existing bars and bolting up the monostrut? Probably with a little minor moving and adjusting of the mounting points?

Powerflex offers both street and race spec bushings for the monostrut... so far the only "race spec" bushings I've purchased from them are the lower front mount shock bushings and at that, I only have the passenger side bushings in. Would the race bushings be that much harsher compared to their street bushings with this application?

 

It would be pretty much as you describe.

If your diff lube has any miles on it at all, I would drain and fill
before the strut goes in and save some grief later. At least clean
the breather.

It can be done with the strut in place, but it is a major aggravation.

Support the entire bottom assembly well, it weighs close to 500 pounds.
Once you have undone the struts, the only thing holding it up are the
two front a-frame bushings. That's sort of like holding a heavy tray
at the very end with a turkey on it.

FYI, those four bushings, plus the front two a-frame bushings are responsible
for locating your two rear wheels.

There is additional compliance at the four bushings mounting the diff, which
locates the inner end of the halfshafts, which is effectively your upper control
arm. Add to that two each at the inner end of the lower control arm.

So fourteen points of compliance in total.

If you harden four, that still leaves ten.

So, the blacks *may* not be too bad.

The difference between the purple and black is, I think, 65A shore and 80A shore.

Of course, you could wait for the monostrut and check the existing bushings.

Consider also that the main improvement comes from the monostrut being a
single assembly without the holes having independent freedom of movement
from side to side. The aftermarket bushings would just be icing on the cake.

Of course, if you go for black I am sure there is no shortage of people waiting
to hear the result.

Put a note on the steering wheel as a reminder if you do not fill the diff
immediately.

ps. I can drive through big sweepers with lots left and watch M3's and Porsches
fade in the mirror as they hit the pucker factor and back off.

 

When I replaced my subframe bushings I made the mistake of only backing the car up on ramps instead of putting it on jack stands and when it came time to put the subframe back on, the whole diff assembly sunk a little and I had a hard time realigning everything. I imagine, I should put the car up on jack stands so there's no load on the suspension?

I have been planning on changing out all my fluids again in my transmission and diff since I used "the cheap stuff" when I first bought the car just to make sure everything was running right and no major leaks. This would be the perfect time to order all my Amsoil fluids I guess.
After I receive the monostrut, first thing I plan on doing is removing the bushings since many people have reported that "their bushings still looked good" but needed to be replaced.

Also from if my logic is correct, installing this monostrut with stiffer bushings (street or race) the car will be more prone to oversteer...?

 

I have the full setup with ARB since that is factory spec in
the X308/R.

It does not oversteer. In fact, the monostrut should reduce
any tendency to snap roll oversteer because it locates the
suspension better. An Alfa GTV oversteers

But, lapses in judgement such as a snap left followed by a
snap right to avoid some moron throwing a water bottle out
the window in a fit of road rage can still make the car feel
somewhat tippy.

The advice from someone who has not done this job ...

the front of the a-frame will act as a hinge

put two jackstands at the jacking points letting the suspension hang

put tires underneath sills as backup

brace under differential with wheeled hydraulic floor jack

the floor jack will let you make any minor adjustments needed

hitting everything with penetrating fluid before the day would be
a wise investment of time

for the diff, I am on Redline 80W140.

make sure you can undo the fill plug before opening the drain plug.

What subframe bushings? You mean the ones at the front of the a-frame?

How did they work out?

If you went purple with those, I guess matching with purple again would
be sensible.

And speaking of the ARB, maybe now is a good time to do the bushings.

BTW, check something for me. Figure out if the rear drops enough to wiggle
out the diff. I have a X300 3.58 + Auburn LSD that needs to be poked in
.... someday
++

 

I began just wanting to swap out the struts for the mono tube but with just jack stands I couldn't get the diff low enough to drop the monotube in. So, I dropped the A-frame and installed the outer bushings as well. I hadn't planned on that part but had to to get the diff low enough to get the monotube in. The other issue I had was that the upper mounting brackets aren't quite wide enough to accept the bushings and bar and it spread on me. The backside of the bracket has a welded nut and to get the bolt to re-align to hit the threads was tough and my driver's side still insn't totally in yet!

I would NOT go with race bushings. The street bushings are just stiff enough without causing issue. I believe the front shock bushings only come in the higher rated black version. The rest of the bushings for the car are "street" as I ordered them. I highly doubt you will regret wanting to switch from purple (street in the case of monotube to black (race).

I did also change out my diff fluid and found that my lower drain bolt was in need of replacement next go around it was getting stripped.
The re-alignment of the diff was a total pain too. Its best to do the a-frame bolts toward the end and located the center bolts first and work your way out for what it's worth.

 

Rumour around the 'net is that powerflex can sometimes
take the attictude that close enough is good enough.

In this case, the bush may be longer than stock because
of the lip which is needed for centering since it is not a
press fit.

If the bracket needs to be spread, it might be a smart
move to hog out the hole a bit on the bolt head side
to allow a little misalignment when inserting the bolt.

I would test the existing bushing by inserting a bar into
the hole and heaving in multiple directions.

I could be mistaken, but I think Jaguar offers two versions
of the bushes. Comfort and Sport. Sport is the XJR application.

Finally, when the a-frame has been shifted, checking and setting
rear toe might be a good idea. Bear in mind that with rear toe,
it must be even on each side, so measuring total toe like the
front is not good enough.

 

There are two versions for factory bushings:

Blue outer paint = comfort
Red outer paint = sport

 

So I wonder if the "race" (black = harder) are really that noticeable versus "street" (purple = less hard, but harder than OEM) in this application?

If anything, I would think that 'noise' & 'vibration' part of the NVH(harshness) ride quality acronym might show up a bit more, but I wouldn't think ride quality per se would as this isn't a direct moving suspension piece.

Thoughts on whether choosing the race or street makes any difference in this application?

.

 

Plums, I already had a rear anti-sway bar added from an XJR, is the monostrut strut still worth adding? My mechanic asked me to do that before I added Andy's front drop links, and now that I've had the rear sway bar, I am ready for more handling improvements....

 

If you are still running the individual dogbones, in my opinion yes.

The advantage of the monostrut is that it ties all four points together
while the dogbones are two independent pairs.

If you have the opportunity to do so, reinforcing the mounts may be
a good idea if you really push hard. Brutal has had these tear out.

Maybe just TIG welding around the attachment point completely
would work.

 

I highly suggest the mono tube for several reasons. I also installed the Powerflex A from bushings at the same time so some improvement can be attributed to that as well. HUGE improvement in 3-4 shift harshness which is all but a faded memory.

 

Have just done mine, what a PITA getting the top bolts to align!

After three days of removing and reinstalling, decided to get a slightly longer bolt and tapered the end into a bullet shape, then whacked it repeatedly with a lump hammer to get it through, then tightened it up.







N.B. Oh, and my 96 sovereign already had the mono tube panhard frame