Strut top movement

[Mikeyman]

Hi All

I've installed K sport adjustable front struts with Super-Pro top mount bushes and bearings. It seems that there is insufficient clamp up between the top cap and the bush when installed and there is movement in the top bush weight on wheels. the build up is correct and even if you just install the mount in the strut cavity with a nut on top and sit the cap on top of the strut tower there is no clamp up. I would say its almost like either the caps are deformed by age or the Super-Pro bushes are not deep enough at the top. Has anyone else run into this issue?

 

[Ginger Beer]

I've never had that issue with OEM or Super Pro strut top bushes with stock dampers, I also have never had that issue with the Pedders extreme coil overs

I would check how you assembled the dampers and top mounts, ensuring that all bushings and washers are in the correct position, especially the washer that slips over the damper that the strut top bush sits on, if that is not in the right spot, or missing even, that could well be your issue

 

[Mikeyman]

Thanks, Ginger Beer, I can confirm all is assembled according to pic on the K-Sport struts, there isn't much you could do wrong. The bearing sits nicely on the machined cup, the washer under the super-pro mount bush, and the washer on top all in the correct orientation concave side down on the lower and up on the top. I can't understand why with the weight on the wheels the bush isn't forced right up into the tower cup but with the slightest pressure on the body, the struts move up 1-2mm. the only thing I can think of is not enough preload on the springs compressing the top bush to hold in the tower cup. That is my next step I'll try and find a recommended spring compression length from K-Sport. I had backed the preload off to try and get better sag when lifting the car. For NZ certification of adjustable suspension there has to be a 25mm (I think) minimum drop from the weight on wheels to jacked hang.

 

[lmoengnr]

Thanks, Ginger Beer, I can confirm all is assembled according to pic on the K-Sport struts, there isn't much you could do wrong. The bearing sits nicely on the machined cup, the washer under the super-pro mount bush, and the washer on top all in the correct orientation concave side down on the lower and up on the top. I can't understand why with the weight on the wheels the bush isn't forced right up into the tower cup but with the slightest pressure on the body, the struts move up 1-2mm. the only thing I can think of is not enough preload on the springs compressing the top bush to hold in the tower cup. That is my next step I'll try and find a recommended spring compression length from K-Sport. I had backed the preload off to try and get better sag when lifting the car. For NZ certification of adjustable suspension there has to be a 25mm (I think) minimum drop from the weight on wheels to jacked hang.

Which version of the Superpro strut tops did you use?
Polylast or urethane?

 

[Mikeyman]

Which version of the Superpro strut tops did you use?
Polylast or urethane?

The Blue ones so urethane I think,

 

[lmoengnr]

These are the urethane version.

The Polylast are a lighter blue.

 

[Mikeyman]

Yes they are the ones

 

[lmoengnr]

Yes they are the ones

Did you lube them up before refitting to the strut tower?
Install the strut assembly to the strut tower, attach the top clamp washer and nut and torque them down before re-attaching the lower control arm. This is to ensure there is no gap between the clamp washer and the strut tower.

 

[Mikeyman]

Hi Guys

Yes, all were lubed and today I pulled both struts double checked the assemble and set the preloads up per KS Racing Australia instructions. Yes, I torque the struts in the towers before connecting them to the stub axles. What do you know exactly the same result.
However I have just checked 2 other cars a 05 HSV GTO (my Neighbor's, 50K on the clock) and my friend's VY GTS both have stock suspension and both have exactly the the same amount of movement at the top of the strut when pushing down on the front of the car. (1-2mm). I guess it makes sense the rubber or urethane is compressible. Seems I had a problem that wasn't one. Cheers for your input.

 

[vxcalais_01]

Hi Guys

Yes, all were lubed and today I pulled both struts double checked the assemble and set the preloads up per KS Racing Australia instructions. Yes, I torque the struts in the towers before connecting them to the stub axles. What do you know exactly the same result.
However I have just checked 2 other cars a 05 HSV GTO (my Neighbor's, 50K on the clock) and my friend's VY GTS both have stock suspension and both have exactly the the same amount of movement at the top of the strut when pushing down on the front of the car. (1-2mm). I guess it makes sense the rubber or urethane is compressible. Seems I had a problem that wasn't one. Cheers for your input.

Apologies as I know its a few months on, but I an using the Nolathane version on these, and Nolathane and Whiteline both mention that the car will sit 10mm higher when using these Poly ones as they compress less. Thats why people use them so they dont fail like the og ones. Just remove the old rubber spring seat from bottom of spring to get the 10mm or so back. You also need to make sure the larger dome washer faces down under it and the top narrow washer faces up. Sometimes people put the larger dome washer on top and as it doesnt have a flat part it can roll and induce play and pressure onto the top plate (rebound stop).