Knocking noise from under boot

Hi all,
Took the disco for it's first drive out today since I got it yesterday, and it seems to have a bit of a problemo, which I'm hoping you guys can help me with.

So basically, it's a 96 300tdi, with no ABS.

First thing I noticed was that the steering was much more vague than my last disco (98 300tdi with ABS), but throughout the day, either this cleared up, or I got used to it.

Some background info:
I was driving along an A road about 50ish mph, and while going round a right hand bend, there seemed to be a bit of a thudding noise (Like driving over ridges in the road, or a flat tyre) from the left hand side. It only lasted while the vehicle was swaying around the corner, and went back to normal when straight or on left hand bends. I carried on and noticed that when the landy was going forward, the steering wheel would be at about the 11 oclock position. I pulled over and there was a hell of a stink, like burning brake pads, coming from the back left wheel. It was very hot to the touch aswell. Left it for 10 minutes, drove on, and all was back to normal with the steering wheel at 12, so I put it down to a sticking brake calliper or something.

The problem:
Anyway, much later on driving home, I noticed there was a knocking noise coming from the rear of the landy, which only seems to occur, when my foots off the throttle. When driving along normally it's not really present, but when easing off the gas for a corner, or when changing gear, the knocking noise is present, and seems to have gotten noticably louder throughout the hour drive home. The knocking also seemed to increase in speed when going faster/ higher revs. There's no dodgy smells again, and the landy still seems to drive as normal.

My guess is propshaft UJ's, or worn bushes, but I've had a good look around all the forums this evening, and some people say this points to diff problems, and others to brake pads which would make sense.

Anyone know of any ways of isolating the possible causes of this, or suffered from similar symptoms themselves?
Cheers.

I had same problem. I thought it was props, diff, brakes everything and it ended up being so simple..... The exhaust!!! The exhaust was knocking on the mud flap mount. Simply cut small knotch out of it and problem was solved! Just wriggle exhaust about and see if its catching anything.

And other problem could be wheel bearings. If they're knackerd it could drag and will get hot as prob no grease left on them. And can also make a hell of a horrible noise. If doing one might aswel do all coz the rest won't be far behind.

Could be a frame ball joint.

Cheers buddy, I hope it is the exhaust lol. I'll check before I take her out this afternoon.
If it's not that, then I'll be underneath tomorrow with a pry bar checking every bit of rubber lol.

MPfive said:

Could be a frame ball joint.

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Yep if it knocks when accelerating and taking your foot off the gas it will probably be the a frame ball joint

Hi,
I have a similar problem and i found the rear shock absorber bush worn, if you get somebody to push up and down on the rear bumper and watch the top bushes on the rear shocks you will see some movement in the bushes if they are worn.

Just had the disco up on the ramps, and had a good look underneath.

I couldn't feel any excessive play in the bushes, I checked all that I could reach with my biggest longest screwdriver, and there were one or two which seemed to give more than the rest, but nothing massive. I also grabbed onto the rear anti roll bar, and gave it a good push up and down, which bounced the truck about above me, but there was no excessive play, in it. I did notice that when I pushed it up and down a few times and let the truck bounce by itself, there was a bit of tapping, but it didn't bounce long enough for me to really hear where the tapping was coming from, perhaps it is linked to the knocking I can hear while driving, or perhaps it's something completely normal. I'm not sure about that. The rubber mounts where the trailing arms attach to the chassis seemed quite split and worn, but couldn't really feel for any play. I also looked at the A frame ball joint, and it looked okay, but not really sure how to tell if it's buggered just by looking at it. The exhaust was very firm, but had a fair bit of give in it. I pushed it left and right and there was no noise made, and it didn't infringe on anything. It was a good inch or two away from the mud flap.

The bad news is that there's a very slight oil leak from the rear diff drain plug, and the good news is that the chassis is about as solid as I've ever seen. It's never been welded, apart from one small patch on the sill. Very happy with that, will get some sealant on there before the worst of the winter.

The results of my first look, are pretty inconclusive. Unless any of what I've said jumps out at you guys?

Now mine has developed yet another noise from underneath. Like a "tinny rattle" when let on and off accelerator. God knows what it is. One thing after another. Felt slight vibration before which leads me to think its prop but the noise just doesn't match a knackerd prop noise. Any ideas?

DiscoNickY said:

Now mine has developed yet another noise from underneath. Like a "tinny rattle" when let on and off accelerator. God knows what it is. One thing after another. Felt slight vibration before which leads me to think its prop but the noise just doesn't match a knackerd prop noise. Any ideas?

Click to expand...

When a uj's on its way out,noises can range from anything from a slight rattle to squeeking like a fan belt.Get under it an have a look as the landy zone crystal balls busy at the mo

The closest thing I can give as an example to what the knocking noise I have described is that it sounds like a PTO shaft rattling on low revs inside a PTO guard.

It's a kind of rackety clattery knocking, but more slowed down, and without the background wurring that you get with a PTO.

Found out what noise was. Uj on front prop at transfer box. Replaced both and running smoother than ever an no noise or vibration. Going to do back ones at weekend. Me
Mates disco clutch is dragging an gettin stuck in gear. Obviously something to do with clutch but what...? Any ideas?

Found out what noise was. Uj on front prop at transfer box. Replaced both and running smoother than ever an no noise or vibration. Going to do back ones at weekend. Me
Mates disco clutch is dragging an gettin stuck in gear. Obviously something to do with clutch but what...? Any ideas?