Rear Bottom Out Issue

[lastdime]

I just made a 1000 mile road trip in my roadster with some fellow Cobra guys. Yellowstone was fantastic! But this time I took a 300 lb guy with me. When we hit large dips or bumps, we could hear the thump of what seemed to be the rear bottoming out. If that is happening, are the coil overs taking all that pressure? There are no rubber bump stops on the rear so I figure that must be it. How much can they take? Any ideas?

[Papa]

There are bump stops on the shock rods on my car -- do you have those? They aren't like a typical stop mounted on a fixed point in the chassis. They are the yellow part in the picture:

https://thefactoryfiveforum.com/attachment.php?attachmentid=84488&d=1524418210

[GoDadGo]

Mine Has Them Too!

Does the IRS not have these these?

[JohnK]

As Papa said, there are bump stops in the coil overs, but the force is still all being transmitted through the coil over. It may be a little less jarring than metal-to-metal contact but all the load is still going through the shock. If yours are adjustable you can try increasing compression damping.

[GTBradley]

Have you checked that you have the correct springs in the car? How much weight were you carrying? I go over the neighborhood hump without slowing and no bottoming.

[GTBradley]

BTW, nice long trip! We're probably going to need pictures...

[jcrumpley]

The IRS shocks have the same bump stop as in the photo above. Are you sure the top of your shock is mounted in the lowest hole in the frame mount?

[NAZ]

Put a set of cushions (bump stops) on your shocks (all four corners). That's the first step and it's a low cost way to protect your expensive shocks. You don't say what shocks you have but here's where QA1 double adjustable shocks come in handy. You can easily adjust the compression damping for the load you're carrying to minimize bottoming by simply turning a knob.

[CraigS]

Or just raise the rear ride height 1/2 inch.

[lastdime]

There are bump stops on the shock rods on my car -- do you have those? They aren't like a typical stop mounted on a fixed point in the chassis. They are the yellow part in the picture:

https://thefactoryfiveforum.com/attachment.php?attachmentid=84488&d=1524418210

I have the KONI coil-over supplied with the kit and they look just like yours. However, on page 91 of my manual it states, "The body of the shock goes toward the top". In your photo the coil-over has the body toward the bottom. Has something changed that I am not aware of? I would sure like to get this right.

[Papa]

I have the KONI coil-over supplied with the kit and they look just like yours. However, on page 91 of my manual it states, "The body of the shock goes toward the top". In your photo the coil-over has the body toward the bottom. Has something changed that I am not aware of? I would sure like to get this right.

If you look at the discussion on this starting in post #32 in my build thread, I think all your questions will be answered...

https://thefactoryfiveforum.com/showthread.php?24916-Papa-s-MKIV-Roadster-Build-9115-(Graduated)&p=285839&viewfull=1#post285839

[lastdime]

If you look at the discussion on this starting in post #32 in my build thread, I think all your questions will be answered...

https://thefactoryfiveforum.com/showthread.php?24916-Papa-s-MKIV-Roadster-Build-9115-(Graduated)&p=285839&viewfull=1#post285839

Thanks Papa. That thread was very helpful.