[gjarnos]

I recently removed the rear air suspension and put on new springs and new struts. The issue is the car feels/sounds like it's bottoming out in the back whenever it goes over a bump. If you sit in the back it's very easy to tell and gives you a jolt. The parts are here that I used:

Sachs 105-841 strut

Amazon.com

Pedders Suspension PED-7643 Pedders Standard Height Springs | Summit Racing

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WHITELINE W72045 Whiteline Coil Spring Pad Bushings | Summit Racing

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Is there something I'm missing with converting the rear suspension? Do I need to replace more parts or have special hardware? Has anyone run into this issue? I first just replaced the struts and drove around for a month or so before I decided to change out the springs too because of bottoming out - essentially the same result occurred but the car was stiffer with the new springs.

 

[globuslive]

Seems like you put shocks for catera but coil springs for gto. Gto coils and shocks are slightly shorter, so I would go with gto shocks instead. I got two cars converted like that and never felt the "bottom" gto shocks are very cheap. Look up on rockauto. I got adjustable koni yellow shocks. They are adjustable and make rear end be very stiff if needed. I like it way better.

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[gjarnos]

Seems like you put shocks for catera but coil springs for gto. Gto coils and shocks are slightly shorter, so I would go with gto shocks instead. I got two cars converted like that and never felt the "bottom" gto shocks are very cheap. Look up on rockauto. I got adjustable koni yellow shocks. They are adjustable and make rear end be very stiff if needed. I like it way better.

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Could you do me a huge favor and send me an exact link for those Koni's you used for your catera's? Also, do you expect those new GTO coils I got to work with Koni's? Thank you.

 

[globuslive]

KONI Yellow Sport Shocks FOR Pontiac GTO 04-06 REAR PAIR (2 Rear Shocks) | eBay

The Koni Sport product line is one of our specialities. Koni serves Sporting Drivers with a carefully designed range of sport shock absorbers. They can also be used with spring kits to lower a vehicle up to 35mm.

www.ebay.com

They are more money than stock gto shocks tho. But it's definitely worth it imo.

If these coils are stock height, they will, since gto stock is lowering for catera. If they are lowered, you might get some interference with suspension parts, too low for us.

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[globuslive]

I also have front struts from gto, but it's custom fit, I don't think anyone else ever run them in catera, if you're not deep diy guy, I won't suggest to mess with it, since you need custom made sway bar links. It's another big improvement. One of my cateras on stock gto coils and stock catera struts, another one on gto struts assembly, and there is significant difference. But easier way to do the same is to buy Opel omega yellow koni set from UK ebay, front and rear, and run with gto coils in them. Both ends gonna be adjustable. But again rear ones better to use off gto, they are slightly shorter, so it's safer against bottoming out and eventually damaging them

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[globuslive]

You can't go any lower than that

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[gjarnos]

Do you think the Koni's and the coils I posted are fine for a 1999?

 

[globuslive]

Do you think the Koni's and the coils I posted are fine for a 1999?

Look it up the place or part number of your coils and their specs. I believe red ones are Lowered for Gto and too low for catera. If they have original height it would work, if not, I suggest you stock gto coils. 1997-2001 are the same suspension wise.

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[gjarnos]

@globuslive The shocks you linked me to worked perfectly. Thank you very much for your help. As a warning to others: Do not use the Sachs 105-841 shock on the rear - link here. Use these instead
KONI Yellow Sport Shocks FOR Pontiac GTO 04-06 - link here