What might the knocking noise from under my Patrol be?

tony bogle
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What might the knocking noise from under my Patrol be?

Unread post by tony bogle » May 27th, 2016, 1:39 pm

Hello all i have a 1997 rd28 gq patrol recently i have heard a knocking noise coming from underneath the patrol at first i thought it was the exhaust got under and checked it and that was not it so i had a real good look but i couldnt find any thing that was loose no nuts or bolts missing everything is tight and were it should be the knocking noise can be heard and felt mainly on the passenger side i can feel it a bit on the drivers side it happens when i go around a corner or take off but never while driving :crazy: its doing my head in would any one here know what it might be cheers

Peter Aawen
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Re: What might the knocking noise from under my Patrol be?

Unread post by Peter Aawen » May 27th, 2016, 2:34 pm

Check the body mounts under the front of the front passenger & drivers doors - if you can see that they are collapsed, or maybe there's just a shiny patch of metal above the rubber to show there's been a lot of movement, it could be that those mounts are getting beyond it &/or the bolts have worn the holes oval so now the body moves & knocks.

Or you might want to check out the seam of the floor pan to the firewall, the spot welds have been known to pull out there, &/or the metal to crack, & those cracks/spots can make a pretty convincing knock as you turn or start driving off.

Another possibility would be either the engine mounts, or the gearbox mount - the rubber in those deteriorates over time & km, especially if oil leaks onto it, & then the metal on each side can knock at times....

There are other possibilities, but those are probably the most likely, altho if you could better describe the noise, it's frequency, & maybe even if you can feel any movement in the floor, 'A' pillar, or anything else, we might be able to narrow it down a bit...
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

tony bogle
Here and there
Posts: 30
Joined: July 5th, 2010, 7:42 pm

Re: What might the knocking noise from under my Patrol be?

Unread post by tony bogle » May 27th, 2016, 2:57 pm

cheers peter i just took it for a drive and it sounds like it is coming from the left wheel area i have recently replaced with new bearings, seals bothsides i poped it up on to the gutter to see if it would make the noise and it did the nocking noises vary they sound like someone is nocking on the front door somtimes it could be 3loud quick nocks then a single then a double especially turning into a left hand corner

Peter Aawen
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Re: What might the knocking noise from under my Patrol be?

Unread post by Peter Aawen » May 27th, 2016, 5:23 pm

Hmmm, loose shock maybe, or worn shock bushes on that side? Top &/or bottom could be the culprit there; or if it only happens while you are turning, if could even be the CV joint... Maybe also worn bushes or worn bolts/holes on the front diff suspension mounts; or, if you've done a lot of off road work or driving on corrugations, it might even be the chassis end bushes on the front leading arms. Those bushes have been known to wear out, so the radius arm moves freely whenever the diff/suspension articulates; or it could be that the metal ring those bushes mount in to have started to tear free from the double skin plate they are welded in to.... (Bloody embarrassing when you are driving up a steep hill in the bush & the front wheels/suspension starts to pull ahead as it drags out of the chassis!! Trust me, I know that feeling!! :o )
An Ex-Service person is someone who thought enough about their country & how great it is, how lucky we are to live here, to write a blank cheque made out to 'The People and Commonwealth of Australia' for the value of 'Up to & including my Life!'

Cornbeef
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Re: What might the knocking noise from under my Patrol be?

Unread post by Cornbeef » June 4th, 2016, 6:52 am

Hi Guys
I recon Peter is right , if your getting a lot of noise coming from under the driver or passenger seat or wheel well area its most likely body mounts or Radius arm bushes , in my case it was both , no noises at all now .
Peter diognosed this for me a few years back and thats what it was .

Happy Trax Cornbeef

tony bogle
Here and there
Posts: 30
Joined: July 5th, 2010, 7:42 pm

Re: What might the knocking noise from under my Patrol be?

Unread post by tony bogle » June 11th, 2016, 11:38 am

Hello peter thankyou for your knowledge i checked what you said to it was none of those it was the left engine mount it had about 15 mm play in it the right one was good in saying that with your help i will now being checking all of what you said every month just to make sure again thankyou

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