Car dipping going under 50ks

[ryan101]

That would be warped discs

 

[brgsv6]

Could be a driveshaft

 

[Asmodai78]

That would be warped discs

this could be your dipping problem as well, at slower speeds the brake pad is able to grip the rotor abit and cause the dip like you were braking at a set of lights and the nose of the car dips down. if that makes sence??

 

[Customcreations]

This is rather an interesting topic but also quite confusing.

If the wheels were out of balance they would cause vibration. Not "dipping".

When you say dipping, to me that means the front of the car drops down which would happen when you brake at lights.

If the discs are warped, you would easily tell they are by the brake pedal pulsing when you brake to slow down at lights, etc.

If the car dips (as in when you're slowing down to the speed you mensioned and the front end drops down like when braking but you haven't put your foot on the brake) then I would say your brake calipers are sticking and grabbing. If the pads are near worn out the caliper will be extended out quite a long way and they don't like it.
That would cause the brakes to easily start sticking (grabbing) and giving that "dipping" effect aswell as warping your discs.
It would also explain your car driving better at higher speed. (until you want to slow and get vibration due to the now VERY hot discs should they be sticking)
Another thing to check is the stabilizer bar (sway bar) rubbers.(even if you've just replaced them they can get chewed up easily if over tightened or due to incorrect install) Commodore sucks for the stabilzer bar system. (If they are gone the car can still seem to drive fairly good at higher speed surprisingly. This I know from my own experience when my rubbers were shot)
The calipers could be sticking even if they have had new pads put in. If they've been hot enough and new pads were put in without greasing (by greasing I mean with Copper grease on the anchor plate where the pads make contact and normal grease to the guide pins).
If the "drive shaft" (which is actually called a TAILSHAFT for rear wheel drive except for independant suspension which have a Tailshaft and drive shafts)
was bad that would cause shudders when driving rather than when braking.
So do you mean the front end dips down?
If so it would be either shocks, sticking brakes or Stabilizer bar rubbers (sway bar).

 

[Pickled]

Yes the car dips down like if you're stopped at a set of lights and you continuously push the brake pedal, then release it.

As far as I know the sway bar bushes are the originals, although when I lowered it I checked all the front end bushes out and they seemed fine which makes me lean more towards the disk rotors/calipers sticking.

 

[Slick6]

I suggested the engine mount because the car can rock and dip and feel like **** to drive.

I've driven a few where one mount was completely disconnected and it felt like I was driving a diesel over a really bumpy road.

It may not be that buts it doesn't cost anything to have a look an cross off the list.

 

[Customcreations]

I agree with Slick6 to the symptoms of a broken engine mount. I just replaced mine. I did'nt mension engine mounts in my list because Slick6 had already suggested it and I think Pickled had said he checked them already.
With an engine mount or both broken (or sometimes due to oil leaks the rubbers get soft and cause the engine to move about a bit more)
The tailshaft can be out of alignment and cause all kinds of vibrations too.
The dipping definately sounds like brakes grabbing.
I noticed you just mensioned LOWERING the suspension. The tyres aren't rubbing are they?

I would jack the front of the car up and give the wheels a bit of a spin or should I say the rotors. BUT IF you do it with wheels off, put at least 3 of the nuts back on for testing to see if the discs turn freely or if they grab. Easiest way to diagnose it or eliminate it from the list.