The task looks a bit daunting and was wondering if anyone has done it. I have the tools, shop, shop manual, lift and have no fear. But its nice to get some feedback before embarking on this.

My goal is to remove the sub frame to carefully inspect the 4 bushings. This is in support of my quest to determine and eliminate my horrendous front clunk that's getting worse.

I have done all the requisite testing the pry bars multiple times and nothing shows up as suspicious. My plan is as follows:

- Replace upper control arms. The ball joint boots are gone. Does not mean the ball joints are bad but they are getting replaced. Parts on order.

If the above does not fix it, then I am dropping the sub frame and replacing sway bar bushings, end links (note that they look and test perfect) and also replace both engine mounts. While the sub frame is out, I will inspect the 4 bushings. If they look marginal, I will attempt to replace them before putting them up on the car. If removing the sub frame ends up being a bitch, then I am replacing them regardless.

The manual calls for replacing all 4 sub frame mount bolts. I have those on order. The front ones are torqued to 100Nm followed by 270 degrees of additional torquing using a torque angle adapter which I have. That seems like an impressing amount of torque and that was the part that scares me a bit. Is this possible with a huge breaker bar?

And, of course, keeping to my style, if this job is undertaken, it will be fully and pictorially documented here.

 

At 270 degrees of additional turn even with a tight thread pitch, what's the likely end torque result? 3x the initial torque spec? I've never heard of that as a torquing specification. That's one big breaker bar to get it loose or possibly requiring air tools.

 

This is on page 755 of the X350 body and paint pdf:

 

Actually these are very long bolts, and will have elasticity in the bolt shank. They are inserted from below, so don't really want to come loose at all, so I suspect the additional 270 degrees tightening is part of the process to ensure they don't get loose. AFAIK there are no lock or tab washers or anything else to stop loosening other than the tightening process.

 

I do have the alignment bolts (tool #502-007) and they are a full 27.5cm long.

 

The upper ball joints without boots would be suspect number one.

A loose joint can cause that clunk.

There are two ways to detect the play ... dial indicator or
by inserting finger next to the two parts that the ball joint
connect and moving the wheel around. On asteroid wheels
this is quite easy because the ball joint can be reached
through the wheel openings. Your wheels may call for
a different approach. Of course, when I reach through
the wheel of a raised vehicle I am very much aware of
whether the vehicle is stable before proceeding.

 

Hi Lagonia,

I hope you discover that you don't actually have to drop the subframe, but if you do, I know you're up to the task.

100 Nm is only 73 ft. lbs., so it's less torque than required for many wheel lug nuts, so you should have no trouble getting the long bolts properly torqued.

The additional 270 degrees of rotation indicates that these bolts are tightened by the "torque to yield" method, meaning that during the extra 3/4 turn of rotation the bolt actually stretches and becomes permanently elongated. That's why new bolts must be used upon replacement.

Cheers,

Don

 

Just wanted to do it. I have two new engine mounts and sway bar bushings and even though I know it won't solve my clunking noise, I went ahead and lowered the sub frame.





Used the Jaguar engine brackets recommended in the book and hooked them up to Harbor Freight engine strattle





Marked all four corners of the subframe. This is where the camber and caster settings are done.





Removed the power steering rack from the subframe. The bushings are *perfect*





Lower front and lower rear arms removed from the subframe. All 4 fushings are perfect





All 4 subframe bushings are perfect. The subframe is lowered enough for me to replace the sway bar bushings








The subframe is out of the way making access to the engine mounts a snap

 

" horrendous front clunk that's getting worse."

Surely it's a strut if everything else is ok?

 

Indeed.

 

Dropping the frame about 12" makes replacing those bushings a breeze as can be seen from preceding photos. The ones that I replaced looked good. They were a bit softer with the ones I replaced.





The one on the left is one of the old bushings I removed

 

I had this special wrench in my toolbox that I never used but it sure s**t came handy yesterday when I was trying to remove the passenger side engine mount:

 

This was tricky. No matter what I tried, I just did not have the right tool in my collection to get the upper nut loose. The A/C line was in the way. I needed a double articulating wrench that I did not have in my collection. A quick search on the Harbor Freight site and a 30 mile trip to my nearest store last night right before closing time allowed me to procure the tool shown below. After that, it was a piece of cake.





Harbor Freightness to the rescue





I just needed it to get the nut loose





After that I used the stubby to finish removing the bolt





Old on top and new on the bottom. I have a nice set of used engine mounts now for my next project

 

Overall, it was successful. Dropping the frame and installing it will cost you about $65 because the 4 subframe bolts need to be replaced.

The front two ones are torque to yield. Stage 1 was 100Nm of torque followed by a 3/4" turn (270 degrees) additional turning. I did need a huge breaker bar for that.

Now I have two new engine mounts, two new stabilizer bar bushings and two new upper control arms. I even put the shitty Arnotts back one last time so that I can test drive it.

But first.... I have to finish putting the valve covers back together.... it is never ending with this car....



Torque to yield for the front 2 sub frame bolts



Before: Sub-frame hanging loose



After: All buttoned up

 

Solid write-up man! Much appreciated! Getting ready to upgrade the sway bars with after market XF units and replacing the shot air suspension with Strutmaster sport coil-overs. Ill post a detailed write-up myself when I do.

 

Wonderful that you have shared all this with us. However is the clunk still there or not ?

 

Indeed it is! The only thing I have not replaced is the Arnott's shocks. I have not ridden the car in the last year or so. My plan is fit the Strutmasters coil overs over the Christmas holiday. I hate loosing air suspension but it will make the car more reliable (suspension-wise) in the long run.

 

Lagonia, you going the strutmasters "sport" route? On sale now for $999.00. I just ordered mine. Say..how much did you get your engine brackets for the over head support for this job?

 

I went with the sport ones for my VDP. They felt overly stiff on break in, but after 5k miles I'm glad I went with the stiffer option. They've softened nicely and the handling is great. I'd be concerned the lighter ones wouldn't be good when I load the car down for long trips, especially with the long wheelbase's extra weight.

 

Not cheap. Brand new, for the pair was $137.32 from
https://jaguar.service-solutions.com/