So totse, I have a problem (I think) with my car.

Basically, recently I've noticed it has been riding abnormally hard, like I'd go over a bump, and there is no give in the suspension at all, just a violent thud.

Also, occasionally, but increasingly frequently, the entire car judders and vibrates when I'm on the motorway. Only on the motorway mind, not round the residential streets. That led me to believe my wheels needed balancing, but!

When the car is stationary, if I drop the clutch suddenly and make the car lurch forwards, I noticed the back end dips more towards the left of the car than the right. It seems to be sat level if I look at it from a distance, and I pressed down on the corners of the car and it rose and dropped normally.

So me and my friend at work get bored and diagnose each others car problems (BMW 318Is fluctuating idle. Air flow sensor? Came up as dodgy in an OBD-II test anyway) and he says that is the same problem he had a while ago, and it turned out to be his suspension bushes.

So, my car is at 82,000 miles, I think they are still the originals, and are they likely to be the cause of my problem? If not, any additional suggestions?

I started three paragraphs with "so". I should expand my vocabulary really.

So you should.

Get it up on some ramps and have a look. If they have mushroomed out around their mounts and are really cracked they need replacing.

I'd get polyurethane bushes if you're going to replace them, I've fitted them before and they sharpen up the steering quite a lot, although they don't do a great deal for the handling overall. They're only slightly more expensive than normal rubber ones anyway. Superflex will probably list for your car

According to occams razor, the ideas I'm coming up with are pretty crap.

Assuming there is only one problem...

...I'm doubting it would be suspension bushes. The only way one side could dip more than the other would be if one of the bushes on one of the sides had siezed. But then that side wouldn't budge at all. And you may get Xtreem boulevard shake in that wheel.

I think it could be a problem with your shocks. Say the one on your left is blown, that would allow the left side of your car to move more than the right quite often (as in the 'dump the clutch' test). It could also explain crappy ride with half of your car jerking up and down undamped. I doubt it would be hitting the bump stops as you would damn well know that and would have mentioned it. At highway speeds, you may be able to hit resonances in some way, though that doesn't sound like what you were describing.

Other than that I don't know.

I think Nereth has touched on the money here with suggesting worn shockers. That's what it sounds like to me, and I've driven a car around with shockers that were pretty much dead weight, so I think that's what it is as it makes the most sense and looks to directly relate to my experience.

Go around some corners and see how much body roll you have. If you've got the opportunity with no-one around for miles upon miles at 4am, test how fast you can drive around a roundabout without starting to let go, then do the same but driving aorund the roundabout in the other direction. Give it a margin for error, and use a small roundabout so you don't have to go insane speeds.

Go over some speedbumps and see how the car acts. How does it feel?

Drive fast over a reasonably large dip in the road and see if your car feels like the body is bouncing on the springs like a trampoline mat when you come out.

Like Nereth said, the 'juddering' could be the worn to hell shockers reaching a resonant frequency. They tend to do that when worn the fuck out, bust mostly on corrugation on dirt roads. Perhaps it is your spring that are worn?



P.S. - A gold star to you for promising to elminate the bad totsean habit of beginning sentences with "So..".
- Yes, fluctuating idle could be caused by a dirty or faulty Mass AirFlow sensor or Idle Control Valve.

If you've got the opportunity with no-one around for miles upon miles at 4am, test how fast you can drive around a roundabout without starting to let go, then do the same but driving aorund the roundabout in the other direction. Give it a margin for error, and use a small roundabout so you don't have to go insane speeds.

Unfortunately that test won't really help, since shocks act to damp movement, and in a steady state situation like a roundabout (which is effectively a tiny skid pad), there will be no movement between the chassis and wheels, except in the first few seconds.

Unfortunately that test won't really help, since shocks act to damp movement, and in a steady state situation like a roundabout (which is effectively a tiny skid pad), there will be no movement between the chassis and wheels, except in the first few seconds.

You're right, I forgot that the springs were really softened out too (due to having to deal with so much more shit since the shockers gave up the ghost), however my aim for the makeshift skid pad testing on the roundabout was to sus out and compare the car's movements.

You're right, I forgot that the springs were really softened out too (due to having to deal with so much more shit since the shockers gave up the ghost), however my aim for the makeshift skid pad testing on the roundabout was to sus out and compare the car's movements.

Fair enough.

IMO the best test is to drive over some speed bumps and see if the car bounces up and down in unison in the back, or if the bouncing is 'out of phase'

Right, I'll have to give that a try next time I head into Middlesbrough, no speed bumps round here.

The only thing I've really noticed over speedbumps is the harshness, but I'll remember to have a look to see how the back acts next time I go over one.

Easy test for blown shocks:

Push down hard on one corner of the car. The corner should go down, come up, then settle back down. If it keeps bouncing, that shock is toast. Repeat at other three corners.

Easy test for blown shocks:

Push down hard on one corner of the car. The corner should go down, come up, then settle back down. If it keeps bouncing, that shock is toast. Repeat at other three corners.

and also, blown shocks mean most of the dampening would be by the springs, which means a bouncy ride going over bumps.

another thing worth while would be to check your motor mounts / snub mount, try to see what speed you get the shudders at, whether it is under acceleration or deceleration, if it is dependent on rpm, gear, etc. just try to eliminate what could possibly be wrong and go from there.

how old is your car? what make/model? if its fairly recent, i doubt the bushings would be bad by now, and that if they are, those powerflex bushings are damn good. a few years back, when we were rebuilding my dad's miata, we replaced all the bushings with powerflex ones. like around $500-$600 for the whole kit. the adjustable c/o's and roll bar really stiffened up that car. handles like a dream. my pop's loved mgb's and the whole small british roadster thing when he was young, and finally got the miata, the spiritual successor of it, minus the reliability issues. that miata is a damn good track toy. its a 92 na with the 96 motor in it, no power anything, including steering.

Some cars are designed to be slightly higher on the driver's side, so that with the weight of the driver they sit level.

Well, I say some cars... I mean the MGB and that's the only example I can think of.

I already tried the pushing down on each corner thing, seemed fine to me.

The juddering doesn't seem to be too dependent on anything really. It stays at motorway speeds, when I first noticed it I coasted down from 85mph to about 60mph, and it was still there. Then I thought it may have been the engine firing on three cylinders, cause last service I did I didn't change the HT-leads, cause the stupid breakerless ignition means I have to trail the leads from the top of the engine block, down the side, then hook them up under the engine, and I was too lazy, but when I put it in neutral it still juddered, so it's not the engine.

Only thing I can think of is it seems to be at one of two points. Either I've just braked heavily on the sliproad because of some cunt not bothering to get up to motorway speeds, so maybe warped discs? Thinking about it, the car seems to lack power too, so maybe the pads are sticking, it takes at least a second to get from 60mph to 70mph in 2nd gear, should be quicker than that.
Or!

Just as the motorway becomes raised over the river. There is a massive expansion strip in the road where the raised section joins the ground, and it is a big ol' bump over that epic expansion strip.

I dunno. But it is really starting to irk me now! :mad:

The vast majority of the resistance you feel when manually pushing on a corner of your car is the springs.

The shocks don't compress fast enough to really start working

have you looked at your shocks? if you have dirt and crud caked around the lower portion that means the oil has leaked out and it not dampening properly. and i know it is late for me to chime in, but it does sound like your shocks.