Big knock on lowered l700

Hi guys. So I’ve experienced this Loud knock from the driver side on an L700 and an L251 charade. The car is on coilovers and it’s only a when they’re wound quite low. But does only seem to be on the driver side and it’s only on big bumps. I’ve had it on both cars running the same suspension. It sounds like the strut is hitting on something but I honestly don’t know and wondered if it was a well known thing when running these cars low.
Thank you!

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Are your running bumps stops? You say “low”, does it coil bind? Many times on lowered cars I’ve seen damaged valving from the shaft bottoming out. Pull the strut out and spring off and see if the strut damper shaft goes up and down at least smoothly.

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Thanks for the super quick reply. Yea I do have the bump stops still in place. Didn’t even think about them! Don’t appear to have spring bind. Sorry I’m a bit of a noob with suspension issues…

Check the bumpstops aren’t smashed to pieces. Look for rust between the coils. Check the nuts on the top of the struts are tight, simply open the bonnet and access the nuts at the top of the strut towers. If you could pull the strut out it’s not hard to wind down the base adjusters to take pressure off the spring (or I prefer to rattle gun the strut top nut off [or at least loose] with spring load on the strut top - consider the risks and hazards - I put my foot on the spring, something heavy behind the rattle gun and strut end). See if the strut pulls in and out at least cleanly. Hard to explain what the resistance should feel but shouldn’t be free nor locked. Also check if the struts have a nut system that holds the internals in, a big nut at the of the strut. These can come loose on rare occasions and the internals move up and down.

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Thank you for the very helpful info. Great knowledge and some things for me to check. Thank you!

Maybe the driveshaft hit the chassis?

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That does make a sound like it. Is it something these cars do when low?