tail happy ti

[zen200]

Hi guys,

I am new here and have found this site to be very helpful so far. However, I have an issue that I cant find a solution to on this forum so I thought I would post in the hope that this has not been covered already.

Problem is that I have only recently purchases my e36 318ti m-sport and since owning it I have noticed that it seems very unsteady at the rear end. When ever i go over a bump in the road if feels like the car is about to spin (from the rear) like a rocking side to side sensation.

Not being that great on cars, I am only assuming that is something to do with the rear suspension (sway bar thingy or similar) but wondered if anyone else has had this happen on there car and what the cure was/is ?

Thanks for read and for your help

Zen

[1996 328ti]

Our cars are a bit twitchy.
You could have some weak or too stiff bushings.

[DSKM3]

I had a similar problem with my ti when I was even doing slight cornering (such as a freeway curve) and the road was a bit bumpy. The rear end would hop and feel quite unstable. For me, it turned out I had a blown rear damper. Since I replaced the entire suspension (the blown damper finally gave me an excuse...), I don't know if just replacing the damper would have fixed it or not. I went from the stock susp to SA Koni/H&R sport set-up and I love it. It's not aggressive enough for the track, but it has transformed this car as a daily driver.

[RedDog]

As everyone has been saying, our cars tend to be a bit twitchy since its rear suspension is quite similar to the E30 but your car might have warn parts too. Do you know if any suspension parts have been replaced on your car? How many miles are on it? If someone sits in your back seat or if you place a little wait in the cargo area does the whole car drop quite a bit?

[zen200]

Originally Posted by RedDog

As everyone has been saying, our cars tend to be a bit twitchy since its rear suspension is quite similar to the E30 but your car might have warn parts too. Do you know if any suspension parts have been replaced on your car? How many miles are on it? If someone sits in your back seat or if you place a little wait in the cargo area does the whole car drop quite a bit?

I think everything (suspension related) is standard and original on car since it was new. Car has done 127,000 miles. I will try taking a pic of car filly loaded up and another one empty to show the travel in the suspension.

thanks for the replies everyone.

[RedDog]

If you have the original suspension then I am sure the struts are shot. I personal feel a BMW needs them replaced at least every 100,000 miles. I also know when I bought mine at 95K it had way too much body lean in the rear and when I replaced it with an OEM type suspension, it was a night and day difference. I would get someone familiar with cars to take a look at your struts.

[zen200]

just to update that I have been told by 2 experienced people that the violent swaying that I am experiencing could be due to warn bushes. The main big bust next to the sill is a commoh fault, but I dont seem to be having the knocking symptoms that is usually associated with this... Either that are shocks. I will update when I get it solved.

[bemadubau]

Zen200,

I have read the replies and I'd like to give you some friendly advice from a mechanic's point of view. As long as the wheels are tightened correctly, there are 4 main problem areas that could use inspection. I will start by listing the easiest inspection areas to the more difficult areas. They go...Shock upper mounting point, the dampener itself, swaybar mounting points, and finally, subframe bushings.

1) The easiest and the most overlooked place to start is the inspection of the rear upper shock mounts. A simple way to determine if the shock mounts are the problem areas is by FIRST, opening up the hatch and removing the trunk lining. The reason for this is so you can inspect the sheet metal around the shock's upper mounting points around the 2 nuts that secure the shock to the body. Make sure the body/sheet metal does not have any cracks or tears. If so, this should be addressed, by structural welding, first before proceeding because it may lead to severe complications.

2) After the body is checked, move to the rear of the car and bounce each corner a few times up and down and let go. The rear shocks should not take any more than 2-3 bounces (depending on the stiffness of the dampening setting) to stabilize itself to a static position. Any more bounces should be suspect for replacement.

3)This is where things could start to get a little dirty. Since the 318ti has the same exact rear suspension setup (except for the 5 lug bolt pattern), they also share the deficiencies. You are going to check for the rear swaybar mounting points. The easier point to inspect is where the swaybar link connects to trailing arm. Simply crawl underneath the rear of the car and visually inspect the small triangular tab that the sway bar link secures to the trailing arm for any deficiencies. With time and spirited driving, these small tabs bend, crack and eventually break creating a sloppy rear end. If you are able to jack the car up or put it on a lift, check the upper swaybar mounting point that connects to the rear floor of the car. If these points tear, it is very costly to repair. A inexpensive prevention is offered by Ireland Engineering that prevents further damage to these trouble areas. As said earlier in another post, it is a good idea to check for the trailing arm's bushings.

4)Lastly, and the most expensive repair is the inspection of the rear subframe bushings. These bushings are circular in shape and are located in the ends of the rear subframe, along the side of the car, at the rear of the rocker panels, before the opening of the rear wheel-well. While the car is lifted safely in the air, this inspection can be performed be taking medium sized prybar and wedge it between the subframe and the mounting point on the body, and wiggle the bar up and down and look for any kind of crack in the rubber or lose play. If so, these need to be replaced. This particular replacement can be extremely time consuming if done by yourself. If taken to a BMW dealership it can also be costly, anywhere between $200-$300, but once it is done, the difference it drastically noticeable.

I hope this bit of information is useful. If you have and question, comments, or concerns, do not hesitate to contact me.

[ChItalian1027]

agreed the subframe is a bitch to replace, i just helped a friend replace his front and rear subframes on his M3, took us three days to do it! we did the replacement last weekend since he is stripping everything out of his M3 for the up coming track season

[pdxmotorhead]

ANother tidbit, tire pressure. Mine at least is fairly sensitive to having a split front to rear.

If you look in the driver rear door sill, its got a little chart for tire sizes and pressures, there is a couple pound difference and mine seems to really like that split or the handling noticeably goes sour.

Dave

[zen200]

Thanks for all the replies guy and gals...

You really are a great bunch on here !!!

I will check all out next weekend and let you know my findings.

Zen