Rear end Bottoming out. opinions? Options

[TravisG]

Hi All,


My 73 914-4, just got on the road (IMG:style_emoticons/default/driving.gif) , will bottom the suspension in the rear when I take off in 1st gear quickly. It will also bottom out at speed if I go over a good size bump. At rest, It sits lower in the back than the front. OK, Now the question: Is it the springs, the shocks, or a combinations of the 2? The car is not bouncy when driving, just bottoms out when driven hard. Also where is the best place to get the springs or shocks?

Thanks in Advance

[SLITS]

You could reasonably test the springs with a known weight. Depending on who you want to argue with, they are either 90 lb/in or 100 lb/in. Generally black paint and one or two green stripes on one coil of the spring. This assumes the stock springs are still on and haven't been changed.

If the trailing arms bushings are worn out, the inner trailing arm mount ovaled or inner mount nut loose .... you'll get some banging around .... and if loose enough, some exciting handling.

So, if you place 90 lbs on top of the spring, it should depress one inch.

[srb7f]

I find it hard to believe that your car truly bottoms out as you have described.

There lots of things that move when the car does the things you describe, and all of them could make noise.

Start simple, with the trailing arms and the bushings between them and the body. Check the status of your rear wheel bearings for excessive play in and out. Check the upper and lower shock bolts.

I would also check the status of your CV joints. Buy a bunch of CV grease, then take off the half-axle shafts, disassemble, and check the inside of the CV joint for deep pits. Re-pack them if they look OK, but replace if they have deep pits worn in them on the inside of the grooves for the bearings. If one of them lets go completely, you won't be able to drive the car.

It's a little hard to describe, but I believe the Haynes manual explains it fairly well. It'll be pretty easy to see once you get them apart.

[TravisG]

I replaced all the cv joints and the boots when I put the new engine about a week ago. It not just a sound that I hear, I can actually feel it bottom out. I have had other cars (non Porsche) that would hit the bump stop and that is what it feels like.

Maybe I should say that the suspension is running its full travel to avoid any confusion about the bottom of the car hitting the road.

I plan on replacing the rear springs, as the shocks seem to be fine (using the push down on the corner and release test).

Is there a practical and simple way to lower the front?