Hi Guys,

I finally finished repairing the rust hole in my drivers foot well and was hoping to get an MOT this summer but have come across another corrosion problem!

The rear A frame is covered in rust and upon doing a thorough hammer test some holes have appeared. A pic of the item in question is below for illustrative purposes, mine is in much worse shape than this!




This part is about £900 new from SNG Barratt, which is quite a lot in my opinion. Used items seem to be in the £400 region too which seems like a lot given the rust has probably already set in (as seen above).

I am considering having one cut from aluminium sheet. Does this sound like a really bad idea? My theory being that aluminium would be much better protected from corrosion and there are metal fabricators out there that can make the same shape from a template for a fraction of the cost. Thickest I can see is 6mm aluminium which should be pretty solid!

Any thoughts on this, for or against?

Cheers,

Owen

 

Sympathise: they are a common problem in salted road areas and the design and rustproofing 'could be better'.

I think you're on a hiding to nothing looking at an aluminium fabrication, it just won't be strong enough, IMO. The original is (I'm fairly sure) made of two pieces spot welded together to form box sections.

Some have sourced a replacement from the US, although freight charges these days are absolutely insane. It's the same part on the X308 (C2N1017), so maybe a local breaker?

 

You would probably be better off making a box section replacement as that would be stronger. I know it would eventually rust but if you rust proofed it yourself and covered it in oil or grease or something it will likely never rust out. It's just the subframe mounts that would need to be fabricated properly.

 

6mm too thin 10mm maybe. and here is the perennial jaguar problem ..If you can weld /fabricate a replacement yourself its no problem but getting it done by another is just insane $$$$$.
Why not get it laser cut in steel. Should be cheaper and stronger.

just found this for £80
Jaguar XK8 Rear Sub Frame Differential Support Bracket | eBay

Think I would phone that looks like a new one .....

 

Wrong part l think.

 

Well the MOT man is not allowed to use a hammer so why did you?
Why not just take it off and get it welded up ....

 

Unfortunately that is not the correct one. The one i need is the frame that lies flat against the diff and spans between the rear wheels. If i could get one for £80 i would snap it up!

I have found a fabricator that will do it from Aluminium or Steel so maybe steel will be stronger, was just thinking aluminium would last longer. The front subframe is made from aluminium and lasts forever.

As with most parts of these cars, the box sections rust from the inside out so i am even concerned about the refurbed ones on ebay that have been sandblasted, etc on the outside.

 

It looked like the surface of the moon and i have seen examples that have completely snapped so i wanted to make sure that if i was going to grind it down and paint it that it was worth it.

I went over the hole thing tapping away and it sounded pretty solid until I hit one part near the middle back edge, where the diff is, and the hammer went through. It was a better safe than sorry type of thing. I'm sure i could have got it through an MOT but i want to drive it without fear too.

 

I am not sure how much it actually does, in strength terms. Obviously you could drive the car without it but from a rigidity point of view i'm not sure it adds a lot of strength, especially when rusted.

This video shows pretty much what I need to do and what could happen if I leave it:

 

But - you're concerned about its rust-compromised structural integrity - that's the point, surely?

Full disclosure:- I'm pretty OCD about critical items, so I wouldn't drive a 155mph 370bhp car around if I thought there was a risk of suspension collapse.

There's one here, complete with the upright. It's in SW France, so possibly from a 0 salt car, although the logistics might be challenging:
https://www.jagpieces.com/berceau-ar...17-c2x27083423

 

Completely agree, which is why I went over it looking for weak points in the first place. My thinking was that a fresh piece of 6mm aluminium would be sufficiently strong when compared to most rusted options available from UK scrap yards.

There seems to be very little mention of this 'A' frame in the Jaguar service manuals (other than removing it for access) which made me think that it wasn't as structurally important as other parts of the overall rear sub-frame assembly

Am very surprised there is no after market option for this part as i would think most UK cars will need one sooner or later. I have seen various additional braces you can buy to reinforce this area, in fact the convertible comes with additional struts that the coupe does not but no replacement solution.

Guess i have to choose between a half battered one for £400 or a brand new one for £900

.

 

I sprayed mine down with fluid film last week. Can't hurt.

 

I think it is very much a vital structural item. There's not much else holding your rear end in place other than a bit of lattice behind the diff.

 

Another "Mechanic" who does not know what a torque wrench is for .....

 

Hi,
Having been inspired by all the forums, I have removed the rear sub frame on my 2005 XK8 S coupe, and on the subframe is a sensor of some sort, I can't see any mention of it anywhere, could somebody tell me what on earth it does.
Regards
Bob

 

It's a ride height sensor for the HID headlamps.

 

I thought it was for electronic shocks, to prevent squatting on acceleration. My links for those sensors, front and rear, are worn falling off the ball mounts

 

HID Sensor links can be made from small Rose bearings. See this thread https://www.jaguarforums.com/forum/x...ge-arm-235204/

 

For any UK owners who may suffer from the same issue as me with the rusty A-frame, I found that ordering a used part from the US much more cost effective solution.

I paid £120 for shipping but given the reduced corrosion problems in the US i managed to get an almost perfect part for only £250 making the total less than the shabby pieces of crap available on ebay in the UK.

The part I received is from a '99 XJR in Texas and had two ten pence sized patches of surface rust on, which I have ground off and repainted easily. Although 3 years older than my own car the condition was amazing.

 

I wander if it's possible to build a new A frame from tubular steel and weld it up. Would be stronger and better then any used part.