Knocking from rear - Snapped spring?

[Rick_1138]

Hi folks,

I have noticed while driving about, especially through villages where you meet a pothole or sunken manhole cover etc. There is a knock when the rear suspension is compressed and released.

I am pretty sure its the offside rear as when I go over a low manhole the nearside just sounds as normal but the offside has a sort of double clunk noise.

I have had the car up on stands to have a look as the only think I can think of is either broken drop links or a snapped spring.

The ABS rubbers look okay, the rear drop links don't have any excessive movement (though I am replacing them soon as done front last month). The rear springs did look slightly different with the spring being wider loops at the top them compressing into the 3 lower loops at the base (if that makes sense) the nearside spring, these 3 lower loops have a 2mm gap or so between each loop, however on the near side they are touching (a bit like if you look at your fingers and have them touching, the near side spring, the fingers wouldn't be touching.)

The spring looks okay on both sides, i.e. I cant see or feel any breaks, but I know this is not a guarantee.

I cant think of anything else that would be causing the rattle, unless the shock absorber itself is gone, but that's unlikely as they look in good condition with no oil seeping past seals.

I am trying to source some OEM rear springs to swap them but before I start unbolting stuff, I just wondered if anyone had any other suggestions.

Other thing is when driving the rear end feels almost squirmy, this could be my imagination, but it feels like the car isn't as stable as it should be which makes me think snapped spring.

 

[G Man]

Check your drop links mate

 

[wj51fut]

I take it this is on OEM suspension? How many miles?

Sounds like something has worked its way loose somehow. Have you had any work done in that area recently? The springs will be slightly compressed whilst they are on the shock, even whilst the wheel is off the floor.

These cars do tend to bang around a lot. Especially with the state of the roads atm.

If it's the rear then they are quite hard to get too unless you pull them out you really can't fully inspect them.

As for the squirmy rear end, they are all a bit twitchy which is why people tend to get a FRSU to sort out the rear geometry. If you haven't had this done then I would thoroughly reccomend it as would others.

If you've checked the drop links then there isn't much else you can do but take the shock out. Doesn't take long but can be awkward putting it back in. I would investigate before spending money tbh.

Adam

 

[Rick_1138]

Yeah, my thinking was probably drop links as the fronts were shagged, burst boots etc but the rears seem in much better shape.

I am going to swap the drop links and R-ARB rubber mounts but that's next month as expensive month so far was April.

The thing is I know that a loud knock can translate to about 2mm of movement in a droplink\mount so it may yet be the droplinks.

I just wondered if a rear snapped spring may be very hard to see, i.e. lopsided car or spring sticking out too much on one side.

Car drives fine and doesn't wallow about, just that knock when rebounding.

Car has done about 100k miles so these are the things that are going.

I know the rear engine mount is gone so sourcing a replacement.

The other thing it could simply be the exhaust moving a bit as the clamp plate on the aftermarket silencer has snapped in 2, and the flange is only being held on with one bolt!! it passed its MOT with this which is odd, its secure on one bolt but it may move a bit when clunking down the suspension...hmmm.

problem is I cant fix the exhaust till I get an OEM back box which is hard to come by, Integrastella (Andy) doesn't have at the moment.

The car had a full alignment done at its MOT when I replaced the front track rod ends and ARB drop links, though there is a clunk at full lock when moving about a car park, though I have been told this may be the top suspension mount as I couldn't see anything when I was changing the drop links...hmm.

 

[Rick_1138]

Well I double checked the new drop links, they are solid and the exhaust isn't touching anything when given a good wrench about.

The issue seemed to get louder, more rattly when I had 2 passengers in the back, so I am pretty sure its the rear suspension.

I am going to check the rear top mount bolts but not 100% sure how I access them, do I have to take half the cars interior apart to get at them to see if anythings loose\eliminate another idea.

Does anyone have any idea what could be causing a rear rattle\clunk when pulling out of junctions turning left\right, and going over multiple bumps\potholes etc.

I cant think whats doing it, and its a deep knock not a little rattle, hence why I thought it was a knackered ARB drop link, bushes on the arb seem okay, not allowing that kind of movement anyway.

Car feels stable on the road, just this clunking, its doing my head in.

 

[Beefman147]

Well I double checked the new drop links, they are solid and the exhaust isn't touching anything when given a good wrench about.

The issue seemed to get louder, more rattly when I had 2 passengers in the back, so I am pretty sure its the rear suspension.

I am going to check the rear top mount bolts but not 100% sure how I access them, do I have to take half the cars interior apart to get at them to see if anythings loose\eliminate another idea.

Does anyone have any idea what could be causing a rear rattle\clunk when pulling out of junctions turning left\right, and going over multiple bumps\potholes etc.

I cant think whats doing it, and its a deep knock not a little rattle, hence why I thought it was a knackered ARB drop link, bushes on the arb seem okay, not allowing that kind of movement anyway.

Car feels stable on the road, just this clunking, its doing my head in.

Did you ever get to the bottom of this?

I am having the same issue. Car is very tight apart from a slight 'clunk' over bumps coming from the back right hand side of the car. Similar to yourself, everything seems to be ok on the underside of the motor.

How do I know if the top mounts are worn/done? Can this be confirmed by visual inspection if I pull back the boot carpets?

Cheers

 

[BataLeon]

Got the same issue too, checking the drop links and top mounts as I'm thinking its those.

 

[bxlheathsupra]

Could be bushes.. my rear end was all over the place on my last track day like i was driving on ice.. found all the bushes were worn.
I didnt have clunks but worn bushes could be the cause.

 

[Johngreen537]

Drop links if its slow speed mostly.

Sent from my Pixel 2 XL using Tapatalk

 

[BataLeon]

Getting all the drop links sorted on mine this month so I'll let you know how that works out for me.