Mk10 rear shocks

I’m progressing with my 4.2 Mk10 IRS rebuild. Unfortunately, 1 of 4 rear shocks is bad. I’m not too much into spending $400 on a set of rear shocks for this one. I’m wondering if anyone knows whether the XJ6 shock is the same - KYB does carry one for that car for about $60 each, and they seem reasonably popular on the forum. Otherwise, I might pirate one from a 3.8 S rear that I have (under a giant pile of other parts). I looked hard for a part number on the bad shock - nothing! Did Girling make the same shock for all the models in the 60s?

I am going to say they fit, and can be used, but there is some difference between what was the original OEM and an XJ6 item, and I think it is the diameter of the shock body, with the XJ item being slimmer.

for the life of me , I cant recall what I used, but I did swap out all 4.

I will check my invoices, and think I may have ordered correct parts numbers from David Manners UK, as they were cheapest for me. (out here in Oz, prices can be pretty gruesome, depending on freight and our local Oz Peso)

I did check this out physically when rebuilding my IRS, as I had an old XJ6 shock, sorry my answer is not definitive

If I was you, and it was convenient, I would buy one and see if it fits, if so replace the other 3, which isnt hard to do, I doubt the very slight difference in car weight would make any real difference

One thing I would try…ring up a shock specialist and ask them if their is a compatibility list on their computer…like I did for the fronts…except do it before you buy expensive “Jaguar” shocks :hot_face:

You are in luck to some extent, as I found these pics in my “420G IRS Rebuild” Folder



I am pretty sure thy came from Manners, but just check those parts nums and see what deal you can get

the 2nd pic is an easy spring compressor using old Jag rear discs

They are 'Boge" MKX/420 (?) rear JC20606/L

Thank you. Tony. I figured if anyone knew, it would be you.
The C20606 is the original parts number for the Mk10/420G and 3.8S, and I didn’t find it cross-referenced to an XJ, which is, as you said, likely somewhat different - not enough cheaper to be worth jumping through the hoops to find out, it seems. I’ve also been dealing with Manners, as they seem to have the best stuff for the big saloons, but they show the Boge shocks as unavailable. Moss has them for $80 each, though. I’m inclined to look for a good used one, as the other 3 seem fine, and probably will last a long time. I can replace them if needed without pulling the whole assembly. Turns out my spare shocks are badly rusted, not worth digging out.
Yes, I’m using the brake rotor spring compressor - works great and very safe, takes about 10 minutes per coilover. IMO, it really is necessary to remove the shocks from the springs to assess whether they are good. I couldn’t tell I had a bad one until I did that.

Could you check with Monroe customer service with weight, height and width of your current shocks to get an inexpensive alternative?


A good thought for the front, but doesn’t work for the rear because that shock incorporated a welded ring to hold the collets which constrain the compressed coilover spring. I don’t think you could add such a thing to a stock shock without ruining it. I did think about using xj6 shocks, but they have a different mounting system than the earlier irs saloons, and I guess would require changing the springs as well. Didn’t seem worth investigating for the small savings. I’ve got a set of GAZ on order, should be here soon, and the restored Mk10 irs is done otherwise, ready to go back in.

Did you install the extension brake bleeding hoses before you reinstall the IRS? It will make future work so much easier.

Moss motors has them but the URL was way too long to cut and paste.


Well yes, but no!
I’ve used the Moss (aka XKs Unlimited) version on an e-type, and I didn’t like them much. I bought a set of Rob Beere remote bleeders, which I believe are superior, although expensive. As I look at the Mk10 rear calipers, I do wonder if they are needed, as access is much better than on an e-type. I am going to try it without, see if I can save the new remote bleeders for my other e-type project. I have a lift, and the Rob Beere units can be added with the cage installed (unlike the Moss unit on an e-type).

Use tiny URL

I’m not sure if our Mark Xs have the exact same rear end or not being that mine is a late 3.8 and yours a 4.2 but I will report that I bled my rear brakes without too much trouble without using any kind of remote bleeders. I found the rear right easier to get a crow’s foot wrench on than the rear left. Not really sure why that was the case but regardless I got both of them bled up satisfactorily. So I definitely think you could save your remote bleeders for another project!

Thanks, Douglas. You should have a different caliper on your 3.8. I put the irs back in yesterday, and am still working to get everything hooked up. I’ve mounting the coilovers on the new Gaz shocks and they will go in tomorrow, as will the rest of the exhaust. I believe the access to the brake bleeders is probably better on my car, but I’ve included a photo. The exhaust is really close to the caliper - is yours the same? I don’t think I’ll use the remote bleeders, but can add them if needed.

on my 420G, they are tight up like that, no room for any fancy bleeder contraptions

shaved down 7/16" spanner, and clean down the brake caliper of fluid straight after bleeding