Hi guys,
Well, I've dropped in a few times over the last while to find answers to various things, but otherwise not been around for a while.

On the big plus side, the RR is still just trucking on. It's been more-or-less my daily driver for the last couple of years and just keeps on doing its thing. I know I'm asking for trouble in saying that....

Just passed it's MOT last week with 2 or 3 advisories - one of which was the exhaust having a mild leak. I also know that my front CATs are knackered (but at least they're quietly knackered, and not making that horrible tin-can noise any longer..) I've also grown too tired of the howling and roaring caused by the previous owner's centre silencer delete.

So it's new exhaust time, or at very least the front pipes and centre silencer. The problem is I find various part numbers for the down pipes. My VIN is A448*** and I get WCD105350, WCD105360, WCD000860.... and I can't readily see any difference. They all seem to say they're OK for a 4.0L V8 with CATs.

Can anyone point me in the right direction please? If there are any pitfalls/obstacles to doing this job I'd also appreciate a 'heads up' - I've seen some references to a gearbox cross member?

Any help and advice gratefully appreciated as always.

Ta.
Donald

The earlier numbers supersede to the WCD000860, the other two (105350 and 105360) are for US models with post cat lambda sensors. So if you get sent one of those, you'll need a couple of bungs (or old lambda sensors) to plug the holes.

Some of the aftermarket ones come in 3 pieces and separate after the cats, they can be changed without dropping the gearbox crossmember. Most come in one piece so you do need to drop the crossmember to get the old one out and the new one in.

I got one for mine from Maltings Off Road (https://maltings4x4store.co.uk/categories/land-rover/range-rover-p38/engine/exhaust-system.html) but the only one they list currently shows the US part number so will likely have the extra holes for the post cat sensors.

Plenty on eBay though, https://www.ebay.co.uk/sch/i.html?_nkw=WCD000860&_sacat=0&_from=R40&_trksid=m570.l1313

Brilliant - thanks very much indeed - I do appreciate it.

The JLR parts finder did show some for overseas markets, so I avoided those, but it was far from clear.

I had also wondered about those bosses/holes on some of the pics, and was going to go out and lie underneath the car to see what the story was - but not a great day for lying under cars today!

I got them for my V8 4.0 from BM Cats.

If you're restoring the missing centre box, check the lengths as shown on the BM website. They do vary from different manufacturers. I had to return one pair to All Parts, because the CAT's were about 50mm too short.

Thanks for your reply Pete, I hadn’t seen it till now. I just went with an intermediate pipe/silencer from one of the LR suppliers.

But everyone will be delighted that I’m back with yet another question!

Today was supposed to be rear brakes on a Skoda Yeti. That was nixed when I couldn’t get the caliper carrier bolts to shift. Allegedly 90Nm, but access is disastrous and even my big Milwaukee impact gun, which can work up to some huge torque, didn’t budge it one mm. Was destroying the UJ and achieving nothing. One for the professionals.

So I thought I could divert onto the RR exhaust… not much luck there either. I’m leaving the downpipes/cats till another day as dropping the gearbox crossmember is not the sort of job I want to do on a whim.

Couldn’t even do the middle pipe as the existing bolt flanges on both the downpipe and tailpipe are probably past using again. I might be surprised when I try cleaning them up, but I don’t want to try that until I have replacements to hand. I’ll need to get some of those “split” versions ( and they all seem to be in Shenzen…)

So, eventually to my questions. The new downpipes have two bosses each (1 before and after the cat). Fair enough, my existing one is the same. “Hopefully” the sensors will come out of the rearmost ones, but whatever bung/plug is in the front bosses is almost entirely gone. I estimate I have 0% chance of those coming out, and even if they did they’d be no use on the rebuild.

1) Looks like the plug is MYB100040L… no longer available. Is the thread a M12 fine pitch? I don’t have anything like that to hand to check. I think I’ve seen some Disco2 versions in stock - would they fit?

2) The workshop manual mentions sealing washers for the O2 sensors, but they’re not shown on the parts diagrams. Again assuming these crumble to dust when I get to that stage, are they just M12 copper?

Ta.
Donald

You should have the sensors in the pre-cat (as in, nearer the engine) holes and bungs in the post cat holes. Bungs with the right thread are often sold as replacement sump plugs.

The O2 sensors come with the sealing washers, much like the washers on spark plugs.

Dropping the crossmember isn't as bad as it looks. You'll need a jack to support the rear of the gearbox, a crowbar to get the crossmember out from between the chassis rails and a club hammer (and another jack) to put it back.

Gilbertd wrote:

You should have the sensors in the pre-cat (as in, nearer the engine) holes and bungs in the post cat holes. Bungs with the right thread are often sold as replacement sump plugs.

Thanks as always - but interesting.. I would imagine that mine is still as it left the factory. Based on appearances, and the low mileage (63k or so) when I got it. I have one sensor each side, and they are definitely
post-cat. The bungs (or what little is left of them) are pre-cat.

I'll see if I can get pics to confirm, but that's the position.

I did wonder about welding a nut/washer into the surplus bosses instead of a bung..?