[SOLVED] Rear End Knock

arblickspule · 13th June 2018, 02:05

After some months frequenting and perusing this lovely forum I did not get to the bottom of the 'knocking sound from the rear' that was bugging me to point of

So, after replacing the upper and lower suspension arms, drop links and a couple of dodgy bushes, and after removing and refurbing the subframe and anti-roll bar and a couple of other bits 'n' bobs still had no chuffing idea what the damn knock was!

Until last Friday...

We chocked the beast on the tow ring (chunk of chassis what sticks out the back) and wedged a 12 foot length of thick walled, rusted, steel pipe under the offside rear tyre and, with a breeze block as a fulcrum, simulated the drive of it's life!

Result...

...was pretty annoying!

The bolt that holds the bottom of the shock absorber is, I guess by design, although who'd design it like that... ...sorry, start again.

The bolt that holds the bottom of the shock absorber to the lower trailing arm had fatigued to the point where it wobbled, imperceptibly, while we were searching elsewhere for the knock, until we finally nailed it.

So first port of call for rear end knocks - since you don't even need to take any wheels off (just jack up until the wheel stops taking the weight) and they cost less that an a quid - Item 3 -> https://rimmerbros.com/Item--i-GRID001548

Image #1 is the test to see, if indeed, the knock was from this bolt. We simply moved the contact point from the sh**ty knackered thread on to the pristine-ish bit of the bolt using a couple o' washers.

Our assumption was that the dire knock was a result of an issue further up the suspension chain and so, being the first bolt we got to and thus the first to be undone and thrown over our shoulder, disregarded it as unimportant. Turns out it was the cause.

Lessons learnt!

Best_of_British · 13th June 2018, 08:42

Result. Thank you for informative thread with pics. I'm about to take tourer of road to rebuild back end as it's on 200k and knocks bangs and skips. Just need to get the Green one on the road, which has been stood for 2 years as replacement.

Jobs like rebuild of rear suspension is what is killing alot of the old diesel bangers

Sent from my Redmi 4A using Tapatalk

minimutly · 13th June 2018, 16:42

Thanks for that, my rear end " bubbub, bubbabub, bubbadub" is driving me to distraction, add the back box banging on the towbar mounting bolt, a front end rattle as well into the mix, and it's not a good experience at the mo.
Will definately check those bolts, but they were fine when I fitted the new upper wishbones a year or so ago.

arblickspule · 22nd June 2018, 07:55

Back box hittin' yer towbar mount!? Really shouldn't be doing that! New rubber mounts, maybe, or just a whole new box. The mounts are complemented by a decent connection to the rest of the exhaust piping so maybe check that too and if there's a an issue grab an exhaust clamp from Halfords.

Front end rattle could be anything. Would start with the under tray as the quick release screws can be a bit funky. If it's a high pitch, tinny type of noise (think tapping a cola can with a screwdriver) then could be the aluminium heat shielding. Had to renew all the connections on mine wiv massive washers where the metal had corroded.

If there's anything I've learnt from my experience with these gorgeous nightmares it's "check the simple stuff first!!!" 😆😭

Typhoon190 · 15th July 2018, 11:20

I've also rebuilt the rear suspension on mine, and it's suffering the same.

Is the washer supposed to sit under the bolt head or between the vibration damper and the shock?

https://rimmerbros.com/Item--i-RYF000170

Thanks.

Ben.

13th June 2018, 02:05	#1
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	[SOLVED] Rear End Knock After some months frequenting and perusing this lovely forum I did not get to the bottom of the 'knocking sound from the rear' that was bugging me to point of So, after replacing the upper and lower suspension arms, drop links and a couple of dodgy bushes, and after removing and refurbing the subframe and anti-roll bar and a couple of other bits 'n' bobs still had no chuffing idea what the damn knock was! Until last Friday... We chocked the beast on the tow ring (chunk of chassis what sticks out the back) and wedged a 12 foot length of thick walled, rusted, steel pipe under the offside rear tyre and, with a breeze block as a fulcrum, simulated the drive of it's life! Result... ...was pretty annoying! The bolt that holds the bottom of the shock absorber is, I guess by design, although who'd design it like that... ...sorry, start again. The bolt that holds the bottom of the shock absorber to the lower trailing arm had fatigued to the point where it wobbled, imperceptibly, while we were searching elsewhere for the knock, until we finally nailed it. So first port of call for rear end knocks - since you don't even need to take any wheels off (just jack up until the wheel stops taking the weight) and they cost less that an a quid - Item 3 -> https://rimmerbros.com/Item--i-GRID001548 Image #1 is the test to see, if indeed, the knock was from this bolt. We simply moved the contact point from the sh**ty knackered thread on to the pristine-ish bit of the bolt using a couple o' washers. Our assumption was that the dire knock was a result of an issue further up the suspension chain and so, being the first bolt we got to and thus the first to be undone and thrown over our shoulder, disregarded it as unimportant. Turns out it was the cause. Lessons learnt!

13th June 2018, 08:42	#2
Best_of_British Gets stuck in Rover 75 Tourer & Arden Green Project Join Date: Jul 2012 Location: Ormskirk Posts: 932 Thanks: 159 Thanked 200 Times in 155 Posts	Result. Thank you for informative thread with pics. I'm about to take tourer of road to rebuild back end as it's on 200k and knocks bangs and skips. Just need to get the Green one on the road, which has been stood for 2 years as replacement. Jobs like rebuild of rear suspension is what is killing alot of the old diesel bangers Sent from my Redmi 4A using Tapatalk

13th June 2018, 16:42	#3
minimutly Posted a thing or two mg zt Join Date: Mar 2014 Location: cardigan Posts: 1,087 Thanks: 28 Thanked 187 Times in 158 Posts	Thanks for that, my rear end " bubbub, bubbabub, bubbadub" is driving me to distraction, add the back box banging on the towbar mounting bolt, a front end rattle as well into the mix, and it's not a good experience at the mo. Will definately check those bolts, but they were fine when I fitted the new upper wishbones a year or so ago.

22nd June 2018, 07:55	#4
arblickspule Newbie Rover 75 Saloon Join Date: Apr 2017 Location: Winchester Posts: 17 Thanks: 0 Thanked 8 Times in 3 Posts	Back box hittin' yer towbar mount!? Really shouldn't be doing that! New rubber mounts, maybe, or just a whole new box. The mounts are complemented by a decent connection to the rest of the exhaust piping so maybe check that too and if there's a an issue grab an exhaust clamp from Halfords. Front end rattle could be anything. Would start with the under tray as the quick release screws can be a bit funky. If it's a high pitch, tinny type of noise (think tapping a cola can with a screwdriver) then could be the aluminium heat shielding. Had to renew all the connections on mine wiv massive washers where the metal had corroded. If there's anything I've learnt from my experience with these gorgeous nightmares it's "check the simple stuff first!!!" 😆😭

15th July 2018, 11:20	#5
Typhoon190 This is my second home MG ZT-T 190 Monogram Typhoon Join Date: Jan 2009 Location: Oxfordshire Posts: 4,707 Thanks: 328 Thanked 557 Times in 443 Posts	I've also rebuilt the rear suspension on mine, and it's suffering the same. Is the washer supposed to sit under the bolt head or between the vibration damper and the shock? https://rimmerbros.com/Item--i-RYF000170 Thanks. Ben.