19 replies to this topic

[Magneto]

I'm working on a buddies car - he just bought it from the other side of the country (US) and the car is in really good shape, solid metal, fresh engine rebuild, runs well.

 

Now to my issue.....it has Spax coilovers from MiniSpares (sticker on the shock)......the problem is there is a terrible rattle that sounds like it's in the suspension, I've had all four of the shocks off the car, dismantled the springs, run the shock in and out a few times etc, all the bushes are good, everything looks in order. I hear it front and rear, sounds worse on the left rear and the right front but I can't pinpoint it. I've been all over the underside of the car, checked the exhaust, looked for loose anything - nothing, it's all tight and tidy. All the suspension looks freshly built, there is no play in any of the parts, all the bushings look fresh etc.

 

The only thing I can think is that the noise is coming from the shocks themselves - internally. The car drives fine, rides smoothly enough and the type of road has little to do with the rattle....I can hear it when backing down my driveway. It looked like the rear shocks had turned at the top and were hitting the body, but I centered them up and it still sounds the same. It's a loud enough rattle to hear it over the sounds of the engine and road/tire/wind noise. One of the fronts the upper bushing had come half way out of the shock eyelet, I thought again the spring must be hitting the upper bracket, so I pressed it back in place and remounted the shock...noise is still there. 

 

Anyone have any similar experiences like this to relate?

 

I hate to have the guy buy a new set of shocks and not have it cure the problem.

 

Looking for ideas at this point........I'm not easily stumped but this one has me scratching my head.

[nicklouse]

So what are the corner weights with driver?

Not set it up like a 4 legs stool have you and you have a loose Spring.

[tiger99]

Or the noise is the seams in the shell gradually coming apart if it has not been strengthened properly for the imposed spring loads which were formerly reacted by the subframes, as designed.

[Magneto]

The body shell is solid, but I will take a close look and see if I can see any evidence of structural failure, now or impending.....as loud as the noise is and the type of noise - a distinct rattle sound as compared to a sheet metal sound - I don't think that's it, but it's food for thought.

 

Nick the car has not been corner weighted but none of the springs are loose with the car on it's wheels...I had it up on the alignment rack and adjusted the springs a little tighter to get a bit more height before I aligned it.

 

So no one has experienced one of these Spax shocks making noise internally?

Edited by Magneto, 08 November 2016 - 03:40 AM.

[Spider]

I make coil over units, though not on a commercial basis and had some experience with them over a good many years. I've found that they are noisy by nature and one reason why I personally no longer run them (I've gone to air).

 

As coil springs of this size and length compress, they don't do so squarely and mid-spring, they do also flex quite a bit in normal operation. It's quite easy for them to make contact with the shocker body and in doing so 'rattle'

 

Sorry, this is the only photo I have to hand (of a later prototype) and it's where I was actually making adjustments to minimise this lean in the spring, but none the less, you can clearly see it here;-

 

 

The speed with which the springs are compressed at will also change where on the spring it will 'lean' so, as does how much it's compressed as I found out, any attempts to correct them is pointless.

 

Putting some thick wall heatshrink tubing on the shocker body will quieten them down, but not make them silent.

Edited by Moke Spider, 08 November 2016 - 05:13 AM.

[nicklouse]

and the above would be my next point of call. 1.9 coil set up are a close to the shock body and the coils are not the stiffest (not much load to carry).

 

as a side note, change the rebound setting as this should change the sound IF it is internal. but I don't think it will change as I don't think that is the issue.

[Spider]

Just to add to what I said above - if it's a road car, I'd suggest going back to rubber cones.

[nicklouse]

Just to add to what I said above - if it's a road car, I'd suggest going back to rubber cones.

that is a no brainer, but "bling".

[Magneto]

Nothing to do with bling, the coils were on it when he bought it. And I've suggested he replace them with smootharides as he's not an aggressive driver. I've got spare trumpets and such so it would be easy to convert it back.

 

I'm probably not giving a good indication of how this sounds.......it's a distinct rattle, sounds like something loose that's knocking hard against something solid. I can hear it when rolling slowly down my driveway, in which case the spring is only moving very little. I've had the shocks off the car and at this amount of compression they don't seem to be leaning in as in Moke's pic. I could see that as you're driving down a road and the suspension is "working", but just rolling back my 30 ft driveway?

 

Like I said, it's a puzzler.......

 

I've had the car up on a 2 post lift several times and checked for anything loose, hanging, exhaust hitting etc, everything looks great. I've taken a rubber mallet to everything under the car and can't duplicate it, so it seems to require the car be on the wheels and moving. The sound to me is definitely in the suspension tho......or suspension related somehow.

 

I appreciate all the thought you guys are putting into this for me!

[Dusky]

Not something in the brake drum?

[Spider]

With the shocks off or even just disconnected one end, is the noise still there?

[Its a min]

Just a thought but are the dust covers still attached to the back of the discs/hubs.

 

They could be vibrating against the disc itself as I found after I overhauled my discs/brakes. Dust covers now removed and no rattle.

 

I hope it's something that simple for you.

[nicklouse]

Nothing to do with bling, the coils were on it when he bought it. And I've suggested he replace them with smootharides as he's not an aggressive driver. I've got spare trumpets and such so it would be easy to convert it back.
 
I'm probably not giving a good indication of how this sounds.......it's a distinct rattle, sounds like something loose that's knocking hard against something solid. I can hear it when rolling slowly down my driveway, in which case the spring is only moving very little. I've had the shocks off the car and at this amount of compression they don't seem to be leaning in as in Moke's pic. I could see that as you're driving down a road and the suspension is "working", but just rolling back my 30 ft driveway?
 
Like I said, it's a puzzler.......
 
I've had the car up on a 2 post lift several times and checked for anything loose, hanging, exhaust hitting etc, everything looks great. I've taken a rubber mallet to everything under the car and can't duplicate it, so it seems to require the car be on the wheels and moving. The sound to me is definitely in the suspension tho......or suspension related somehow.
 
I appreciate all the thought you guys are putting into this for me!

Then I would be looking away from the shocks/coils then.

[wile e coyote]

Just a passing thought with no basis in experience but the recess in the rear wheelwells for conventional dampers is fairly snug - with a little spring deformation as ably demonstrated by Moke Spider - the deformed spring could make contact..... that 'd make an almighty annoying  row.....

[Magneto]

Thanks Wile E Coyote, in order to fit the coilovers you have to open up the area at the top, this was done on this car.

 

I also took a rear drum off just in case, all new brakes in there, from the backing plates out so no joy yet.

Attached Files

•  WP_20161106_21_08_59_ProR.jpg   30.8K   11 downloads

Edited by Magneto, 10 November 2016 - 02:58 AM.