Freelander 1 Annoying clunck!!!

Evening all,
The annoying clunck started life as an annoying click. I bought the hippo two years ago,and after reading all the tales about the vcu, I removed the propshaft and ran in mondo mode for several months. I saved up and had a recon vcu fitted, this is when the annoying click was born. It was only a light click, from the offside rear, after changing gear, and pressing the throttle. But now it has become the annoying clunck!!
Same scenario, change gear, press throttle, clunck from offside rear. Or when driving at say 40mph, and I take my foot off the throttle for a second, and then back on, clunck from rear. To me, it sounds like some slack being taken up on something on the rear end.
Any input welcome, thanks.

sounds like center diff mount

Or broken captive nut in chassis at rear subframe, osf mounting.

They sound like the 2 best places to start looking. The diff mount being refereed to is the 'front' one of the 3 supporting the rear diff - give it an inspection. The broken captive nut sounds nice an simple - so the onerous name for it on here is "broken chassis" or "cracked chassis" - have a search to find out how to check for it. It hasn't been reported for a while, so like earthquakes, we're overdue for 1!

Grab the rear propshaft near the back axle and push it around. If the diff moves more than a few mm then your diff mount is shot. Mine was replaced 8k miles ago by previous owner but is completely knackered. Either a cheap dodgy part from fleabay or the stiff VCU killed it or a combination of both.
Unless of course freelance and Grumpy are right.

The front diff mount was changed when I had the vcu done, and I have'nt done many miles since then, but if I feel fit enough i'll have a look tomorrow.
I'll also do a search for any captive nut threads, and check this out too.
Thank you.

Is it definitely from the rear? I have a similar clunk under the same conditions, as if an axle is taking up a few mm of slack before engaging, however my propshaft is removed and polybushes fitted at the rear. No signs of captive nut being broken either so will be looking at the front offside driveshaft next.

I have what I can only describe as a knock from the front offside. I thought it was the shock but it's only evident under drive. It completely vanishes under coasting or gentle braking. I've a spring that pongs on large front axle articulation too. Just another noise to address when I get time.
There are multiple sources of knocks, bangs and thumps on cars. It's finding them that is the challenge.

I managed to have a look underneath today. I pushed the rear prop with my foot, and the centre diff mount was okay. I found that the rubber around the front vcu bearing had collapsed, and there was a bit of play there. I could also turn the props about a 1/4 of an inch back and forth by hand, and when I did this, I found the clunky sound coming from the ird. Looks like a sleepless night for me

Have you done the one wheel up test? If the test is showing that the VCU is stiff, then it's likely the IRD is on it's way out.

I think even with a perfect IRD, you'll be able to rotate the prop some and 1/4" isn't much. Similarly when the slack is taken up there will be a clunk as the metal gears touch/engage. Was there any lateral movement of the pinion on the IRD? - there shouldn't be any.

If you suspect the IRD - start with doing an oil change on it. The oil colour will probably tell you whether its OK or not. Greyish indicates ground down bearings.

I did the one wheel up test today. 1.2 metre bar and 5kg weight took 35 seconds from 45 degrees to horizontal. I think this is o.k.
I also found that the front stud, on the front diff mount was loose, so I tightened it up.
There was no lateral movement of the pinion on the IRD, so I think i'll change the propshaft bearings and see how it goes.
Any advice welcome, thanks.

35 seconds is about right for a new unit so happy days there. If the bearings weren't changed at the same time or cheapo ebay ones fitted then that is the logical place to start.

The bearings were fitted at the same time as the VCU, at the end of January 2015, and i've only done 4144 miles since.
I thought they would have lasted longer than they have, but as Alibro as said they could have been cheapo ebay ones, who's to know.
I'm a bit doubtful of the front diff mount now, as this was changed the same time too.

Sometimes VCU bearings are mounted badly (not dead straight with the VCU) which kills them quickly as the rubber mounts are deformed the whole time. There are lots of threads here where people got a very short time from new ones but we don't know for sure if the reason was cheapo bearings or incorrect fitting or a combination of the two.

I just read you got your VCU refitted by Bell in the VCU torque test thread. They have a good reputation here so might be worth calling them and explaining the problem.

That could be the reason why it's the front one that's gone and the rear one is o.k.
I'll change them both and follow Hippo's guide on removal and fitting.

Bell gave a 12 month guarantee on the VCU so it's up now, I expect they would put the bearing down to wear and tear, so i'll just get new one's
and have a go myself.

I think they would be embarrassed if their bearings only lasted 4 thousand odd miles. Unless it is a big issue distance wise to bring it back to them I'd be giving them a call.
Apart from that there could be some other issue going on that they might spot.

brownie55 said:

That could be the reason why it's the front one that's gone and the rear one is o.k.
I'll change them both and follow Hippo's guide on removal and fitting.

Click to expand...

Front bearing almost always fails before the rear bearing. I suspect that it being in direct line of spray from the front tyres has something to do with it.
I'd definitely contact Bell though as 4K miles isn't far really.