Bump steer?

bmw

#1

When I hit bumps in the road, car jerks quite violently to the right. I know how bump steer works but don’t know what part could be causing this.


#2

Damaged/worn/loose suspension component. This is more that ‘bump steer’.


#3

This sounds unsafe. Get the car to a mechanic right away for a thorough front-end inspection.


#4

I think OP must have a broken suspension part. Spring, strut attachment point, stabilizer link, etc.


#5

Maybe we can guess what kind of car it is first. My money is on a Studebaker.


#6

Year. make, and model would help.

But yes, you either have suspension problems or very low tire inflation.


#7

If it was a Studebaker, the problem wouldn’t be the steering. It would be backfiring. The reason I say this is b/c my family had a Studebaker, back in the 1960’s. I think it was a 1940’s model. whatever it was, whenever you drove that car uphill it would backfire like crazy. I thought that feature made it the coolest car ever!!


#8

The only reason I quit buying Studebakers was they quit making them.


#9

Bumpsteer is a function of the geometry of the suspension. As many others here have already posted, you have something worn of broken causing the the car to jump when hitting a bump. Grab each of the tires and try to turn them (steer them) by hand. Watch the steering wheel when you do this at the fronts. If any of them move without the steering wheel, look for a broken component at that corner.

Failing that, get the car up in the air, lift of jackstands and start looking for broken stuff, leaking shocks or struts or things that are loose that should be tight. Do’t forget to inspect the strut top mounts, too.


#10

It’s a 99 BMW 323i


#11

Copied from a BMW E36 model (which yours is) forum on things to watch out for. The Bold is from me.

"Suspension.
Front Lower Control Arm Bushes. The rubber bushes which isolate unwanted vibration during braking perish much like the rear shock mounts. They start to develop small tears and cracks, then progress to completely breaking out of their mountings. The normal symptom is vibration in the steering wheel under light braking. If left it will result in uneven tyre wear. Larger than standard tyres/wheels amplify the symptoms.

Front lower swivels, these are rubber mounted and common after time for the rubber bonding to come detached from the metal collar that surrounds it,they then drop onto the metal “bridge” that sits under the swivel, it then causes a knocking noise and excessive play from the front wheels. A special tool is required to replace them unless you like making work for yourself.

Knocking from the front suspension when going over bumps, or when throwing the car from side to side can be worn out front anti roll bar links, a cheap and easy fix.

Rear Shock Mounts. The upper shock absorber mounts are a normal wear item. As they age and get more mileage on them they perish and split, their condition goes from being slightly cracked(nothing to worry about yet) to completely broken out (causing rattling or banging going over bumps). Also the metal around where the rear shock top bolts to can split and eventually break through, leaving the shock to flail around, Strengthener plates are available.

Rear Trailing Arm Bushes. If the rear of the car feels unstable over bumps or when cornering hard and is accompanied by a knocking sound then checking the rear trailing arm bushes out is a good idea, over time they get weak/perish and split away from the mounting(s), resulting in excessive movement of the rear trailing arm(s).

Rear suspension springs are common for breaking, if your car looks excessively low on the rear from one side or both sides then you could well have a broken spring(s). Not a big job to do, a relatively easy DIY for the home mechanic."