Knocking noise after tough dog suspension lift

[Johnkathy81]

Have a knocking noise for a while now since I installed my "2" tough dog suspension lift.

They are foam cell shocks and front struts were preassembled. Dose not always happen, although if I go over speed humps a little quick (not fast) and the front end drops it makes a knocking noise. Hence any time the front drops a little.

Have no spacers installed either.

Any advice or anyone who has experienced a similar problem would be appreciated.

 

[Johnkathy81]

Anybody?

 

[LEIGHTO#L80]

No marks on your coil hats from the upper control arms hitting? all bolts on top of strut are tight?

 

[Johnkathy81]

No marks on your coil hats from the upper control arms hitting? all bolts on top of strut are tight?

Yeah have checked few times that everything was tight, even last night again. I have checked for signs of any marks although cannot see any. Didn't think they would contact as have no spacers but could be wrong I guess.

 

[Cobez]

Leaf spring hangers?

 

[Johnkathy81]

Leaf spring hangers?

Na mate it's the front end only the back is ok! Don't think it can be bushes as car is not even 6 months old.

 

[WarD40]

its the upper control arm making contact with the top of the strut housing my nav did it before and after having spacers installed. only way around it is to go very slow or get adjustable UCA which are anywhere from $500 to $800 depending on who you ask and where you get them.

cheers

 

[Johnkathy81]

its the upper control arm making contact with the top of the strut housing my nav did it before and after having spacers installed. only way around it is to go very slow or get adjustable UCA which are anywhere from $500 to $800 depending on who you ask and where you get them.

cheers

I suspected it could of been that, but have no signs of marks anywhere. As I don't have spacers installed got told that it should not be the problem but then again I could be wrong.

 

[Johnkathy81]

You say before and after the strut spacers.. Did you have standard suspension lift also (new shocks and springs) when it first started also?

 

[Zakka]

It would be your shocks ' topping out' over extending, the rebound dampening ( the speed at which the shocks extend ,is too fast, hence the thumping/knocking/ banging noise as you drop over a sharp edge, IMO most manufacturers do not increase the rebound dampening of there shocks with higher spring rates ie lifted coils.
It happens easily with this type of strut as there is minimal travel, the strut does not have to extend far to ' top out' get to its full extension.
The worst scenario is standard shocks with hd/ lift coils, the valving inside the shock just cannot control the spring.
Not much you can do about it unless you go to a higher end strut where the valving is matched to the spring rate.

 

[Johnkathy81]

It would be your shocks ' topping out' over extending, the rebound dampening ( the speed at which the shocks extend ,is too fast, hence the thumping/knocking/ banging noise as you drop over a sharp edge, IMO most manufacturers do not increase the rebound dampening of there shocks with higher spring rates ie lifted coils.
It happens easily with this type of strut as there is minimal travel, the strut does not have to extend far to ' top out' get to its full extension.
The worst scenario is standard shocks with hd/ lift coils, the valving inside the shock just cannot control the spring.
Not much you can do about it unless you go to a higher end strut where the valving is matched to the spring rate.

Hey mate, I'm sort of understanding most of what your mentioning here although should that be happening as they are pre done and brand new shock and spring to suit from tough dog? Shouldn't they be liable as they sell them designed to be matched and go straight in.

 

[Zakka]

The problem is from my understanding that the valving inside the shock is a ' one size fits all scenario' so the ' light duty' struts will have the same valving as the ' heavy duty' struts , all there changing is the coil spring rate, the lift is achieved by using a thicker coil which when compressed will spring back ' rebound ' very quickly.You would find on the light duty strut ' top out' would not happen nearly as quick , as the shock does not have to retain as high a spring tension.
You are right , the valving should match the spring , but as these struts are mass produced changing valving to suit spring rates on every make and model would eat into there profit margin.

 

[Johnkathy81]

The problem is from my understanding that the valving inside the shock is a ' one size fits all scenario' so the ' light duty' struts will have the same valving as the ' heavy duty' struts , all there changing is the coil spring rate, the lift is achieved by using a thicker coil which when compressed will spring back ' rebound ' very quickly.You would find on the light duty strut ' top out' would not happen nearly as quick , as the shock does not have to retain as high a spring tension.
You are right , the valving should match the spring , but as these struts are mass produced changing valving to suit spring rates on every make and model would eat into there profit margin.

Makes sense, guess will have to try get it checked out and be certain it's the cause and if so will make tough dog liable to try get it soughted.

 

[Zakka]

Ideally a shock should at normal ride height sit in the middle of its travel.This way it has it's best chance of achieving even travel.
A test you could do to see wear your shock is sitting at ride height is,

Jack and secure your front end up on flat ground so the struts are at full extension,

Mark on the shaft the halfway mark with a marker and measure the shaft length ,

Now let the car down and drive it forward and back a little to settle the suspension ,

Now measure from the half way mark , ( If it is not sitting at that point) down to the top of the shock body, from there you can do the math to see how much down/up travel you have.You may be surprised how close to full extension the shock is sitting.

This is good ammunition if you plan to make a complaint.

 

[Johnkathy81]

Ideally a shock should at normal ride height sit in the middle of its travel.This way it has it's best chance of achieving even travel.
A test you could do to see wear your shock is sitting at ride height is,

Jack and secure your front end up on flat ground so the struts are at full extension,

Mark on the shaft the halfway mark with a marker and measure the shaft length ,

Now let the car down and drive it forward and back a little to settle the suspension ,

Now measure from the half way mark , ( If it is not sitting at that point) down to the top of the shock body, from there you can do the math to see how much down/up travel you have.You may be surprised how close to full extension the shock is sitting.

This is good ammunition if you plan to make a complaint.

Thanks a lot for the feedback.

Will definitely be having a good look at it over the weekend and will try as you mentioned.

 

[Zakka]

Cool, no worries, good luck.

 

[Johnkathy81]

Ok so just jacked up car from chassis to allow droop and realised passenger side just contacts uca and few mm gap on drivers side I'm guessing this is the problem??

Might try put a piece if rubber or something there then go for a drive.

 

[Johnkathy81]

Doesn't seemed to have done anything, will have to check shocks when have more time on weekend but have a pic of rubber around Sway bar which I'm not sure if it's normal ??

 

[Zakka]

You could touch up the lip on the coil bucket 5 mill to give the control arm a little room, have seen this done, would not weaken it, make sure to spray it.
The sway bar bush is a split design, so that is normal, not to say it's not metal to metal there though,undo the 4 bolts, not the links and swing it forward and check for metal to metal contact.
Also make sure the strut top nut, the nut inside the coil bucket has not backed off allowing more down travel hence the control arm to coil bucket contact. You will need to hold the shock shaft at the top with vice grips while you crank the nut with a spanner.

 

[Johnkathy81]

You could touch up the lip on the coil bucket 5 mill to give the control arm a little room, have seen this done, would not weaken it, make sure to spray it.
The sway bar bush is a split design, so that is normal, not to say it's not metal to metal there though,undo the 4 bolts, not the links and swing it forward and check for metal to metal contact.
Also make sure the strut top nut, the nut inside the coil bucket has not backed off allowing more down travel hence the control arm to coil bucket contact. You will need to hold the shock shaft at the top with vice grips while you crank the nut with a spanner.

I'll try hopefully to give all your advice a go this weekend or soon as I can find the time, let you know how I go with it all.

Thanks for the help mate!