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Late-style XJ40/X300 suspension on early XJ40

BiTurbo228
Posts: 22
Joined: Wed Jul 09, 2014 10:52 am

Late-style XJ40/X300 suspension on early XJ40

Postby BiTurbo228 » Thu Mar 26, 2020 3:33 pm

Hi all,

Quick question. Is it possible to retrofit late-style XJ40/X300 rear suspension onto an early '40? I know they differ with the cast wishbones and shock arrangement, but is the spring seat on the bodyshell the same design between the early and late XJ40 and the X300?

Mainly looking for an anti-roll bar for the rear.

katar83
Posts: 2864
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: Late-style XJ40/X300 suspension on early XJ40

Postby katar83 » Fri Mar 27, 2020 9:22 am

Was wondering this recently too and my thinking is that it will fit fine. You'll need a different wishbone tie too but they normally come with the wishbones as a pair, I think there is one on eBay right now for £100.
Anti roll bar plus xj8 monostrut instead of individual diff struts is a huuuuge upgrade and completely transforms how the car handles at the back, can highly recommend it.
Not an easy job either, lots of heavy and award stuffs to undo and handle but we'll worth it in the end.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

BiTurbo228
Posts: 22
Joined: Wed Jul 09, 2014 10:52 am

Re: Late-style XJ40/X300 suspension on early XJ40

Postby BiTurbo228 » Fri Mar 27, 2020 11:08 am

Yeah I was thinking it would be a good upgrade! I've already got an X308 triangulated brace so that's one thing off the list ;)

I spotted the wishbone set on eBay. I've actually ordered just the ARB and bracketry to see if I can find a way to fit it to the early '40 wishbones. Looking at the spare suspension I have it's not going to be easy, and might not work even with chopping bits around, but worth a shot I thought seeing as I already have lowering/stiffer springs for the early type suspension :)

BiTurbo228
Posts: 22
Joined: Wed Jul 09, 2014 10:52 am

Re: Late-style XJ40/X300 suspension on early XJ40

Postby BiTurbo228 » Fri Mar 27, 2020 12:33 pm

There's another interesting setup on eBay at the moment which has got me thinking about possible alternatives if the rear-mounted one doesn't work.

Image
Last edited by BiTurbo228 on Fri Mar 27, 2020 1:08 pm, edited 1 time in total.

katar83
Posts: 2864
Joined: Tue Aug 23, 2011 11:17 am
Location: Cambridge

Re: Late-style XJ40/X300 suspension on early XJ40

Postby katar83 » Fri Mar 27, 2020 12:40 pm

Problem with early wishbones is, they don't have an eye for ARB in the wishbones so not sure how would you attach it. They are cast too, so I cant think of a way to safely and securely attach ARB to them.
1997, 4.0 LWB X300 - Unlucky car but still a daily driver.
1988, 3.6S XJS - Never ending restoration project.
1994, 3.2S X300 - Accident damaged, October 2015. Gone!
1994, 3.2S XJ40 - Long gone.

BiTurbo228
Posts: 22
Joined: Wed Jul 09, 2014 10:52 am

Re: Late-style XJ40/X300 suspension on early XJ40

Postby BiTurbo228 » Fri Mar 27, 2020 1:14 pm

I was under the impression that the later wishbones are cast, but the earlier ones are pressed and welded steel so welding a bracket onto them should be dead easy :)

Even if they are cast, so long as they're cast steel it should weld fine (the rear vertical links on Triumph Spitfires/GT6s are cast steel and you can add new brackets to them fine). It's just cast iron that's a royal pig to weld.

naki_k
Super Moderator
Posts: 28977
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: Late-style XJ40/X300 suspension on early XJ40

Postby naki_k » Sat Mar 28, 2020 11:38 am

BiTurbo228 wrote:There's another interesting setup on eBay at the moment which has got me thinking about possible alternatives if the rear-mounted one doesn't work.

Image


That’s the Harvey Bailey rear ARB.
The X300 parts will fit too, but don’t forget you will need different rear shocks/ springs. Standard 40 versions don’t fit.
I have spares here. All x300 Sport and XJR6 models have the rear ARB. I have to say it’s well worth it. They do make a noticeable difference in handling.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6 x2
93 6.0 XJ81 XJ12
94 4.0 XJR
94 4.0 Daimler
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300

naki_k
Super Moderator
Posts: 28977
Joined: Sun Feb 21, 2010 9:25 pm
Location: Kirton, nr Boston, Lincolnshire

Re: Late-style XJ40/X300 suspension on early XJ40

Postby naki_k » Sat Mar 28, 2020 11:40 am

BiTurbo- you have a PM.
88 3.6 XJ6 PDH/CEM
90 Range Rover Vogue SE 3.9 V8 LPG
91 4.0 XJ6 Manual
92 4.0 XJR Manual
92 4.0 XJR
93 3.2s - 4.0 Manual conv
93 4.0 Sovereign
93 6.0 XJ81 DD6 x2
93 6.0 XJ81 XJ12
94 4.0 XJR
94 4.0 Daimler
96 4.0 X306 XJR
96 4.0 X300 D6
97 4.0 X300 Sport Manual
2000 LR Discovery ES TD5 A
Breaking 40/ 300