E36 wandering over bumps

[RobM77]

I've got a 77k mile 1998 E36 328i sport coupe, and it wanders like crazy over the bumps. You more guide it than steer it down a bumpy road - it can shift as much as a foot to the left and right everytime it hits a bump. Rather scary on the lanes near my house, as there's only inches to spare when passing another car.

Any ideas? I had the front suspension bushes replaced, assuming it was those, but it hasn't changed anything. I did speak to a knowledgeable guy who said that they all do it, and he'd uprated the bushes on the front of his car to solve the problem.

thanks.

[E30M3SE]

How old are your shock absorbers? Originals still on the car?

[pstruck]

My old E36 used to wander. Jacked the front up and was alarmed to find that I could move the whole N/S wheel/suspension assembly around. Local Indy replaced lower rear wishbone bushes and problem solved.

The slock prior to repair was also apparent by a 'knock' when I jabbed the brakes.

[RobM77]

E30M3SE said:

How old are your shock absorbers? Originals still on the car?

Yes, original dampers all round. I started a thread a few months ago on this actually. Previous E36 experience tells me that they need changing soon. I was going to go for the original ones (who am I to differ with millions of pounds of investment and testing at the Nurburgring?), but for about half the price I could get Bilstein replacement suspension all round. I've got an Elise to put a grin on my face though, the 328 is just my comfortable long distance and load carrying car. I do love driving though, and always drive with enthusiasm. Any thoughts?

[Shropshiremike]

When did you last do your RTAB ( and yes I know we're talking about the front end but it's amazing how much steer effect a wandering rear end can have! )?

I'd be checking wishbone bushes, ball joints, tyre pressures and tread pattern and as above

[RobM77]

Shropshiremike said:

When did you last do your RTAB ( and yes I know we're talking about the front end but it's amazing how much steer effect a wandering rear end can have! )?

I'd be checking wishbone bushes, ball joints, tyre pressures and tread pattern and as above

Thanks, but sorry, what's RTAB? Rear trailing arm bushes?

I should say that when I bought the car in January I put four Bridgestone Eagle F1s on it and had the geo checked fully. I always run correct tyre pressures, and check that these are spot on every week.

It's in for a service tomorrow, so I'll ask them to have a general look over.

[Shropshiremike]

RobM77 said:

Thanks, but sorry, what's RTAB? Rear trailing arm bushes?

It's in for a service tomorrow, so I'll ask them to have a general look over.

Spot on!

[Madeira]

You'll find also that if you stick quite agressive directional tyres on they tend to wander and tramline alot more than a less agressive tread pattern. What tyres did you have on before?

I'd be getting the RTAB's checked (as mentioned above). Both of these things could well be contributing to it. I get it a fair bit on my 95 328 coupe, it often snatches similar to how you mention but i have got very worn suspension on mine which desperately needs sorting.

[RobM77]

Madeira said:

You'll find also that if you stick quite agressive directional tyres on they tend to wander and tramline alot more than a less agressive tread pattern. What tyres did you have on before?

I'd be getting the RTAB's checked (as mentioned above). Both of these things could well be contributing to it. I get it a fair bit on my 95 328 coupe, it often snatches similar to how you mention but i have got very worn suspension on mine which desperately needs sorting.

The tyres were different all round and old so I changed them within two days of buying the car! My old '93 E36 325i had directional F1s on it and it was fantastic - although the '98 328i sport runs 245s at the rear, so that could cause it. I don't think the 325i was much more than 200.

Sounds like it needs a good check over at the rear (front bushes were done in December), and maybe that new suspension I've been umming and rring about since before I bought the car may need to go on! If anyone's got any comments re: original equipment vs Bilstein I'm all ears. My local garage will fit it if I get the parts for them. I'm just really unsure about lowering the car because I love the way it handles and rides; I just think it needs fresher damping all round.

Thanks for all your help so far

[Shropshiremike]

Madeira said:

You'll find also that if you stick quite agressive directional tyres on they tend to wander and tramline alot more than a less agressive tread pattern. What tyres did you have on before?

Yep - that was on my list of suggestions as well - directional tyres will often "grab" at cambers/longitudinal ridges.
I've found Conti Sport Contacts pretty good for not tramlining on mine

[Shropshiremike]

RobM77 said:

E30M3SE said:

How old are your shock absorbers? Originals still on the car?

Yes, original dampers all round. I started a thread a few months ago on this actually. Previous E36 experience tells me that they need changing soon. I was going to go for the original ones (who am I to differ with millions of pounds of investment and testing at the Nurburgring?), but for about half the price I could get Bilstein replacement suspension all round.

Just as an aside Rob, I noticed in another thread you said your 328 was a Sport? If that's the case the OE dampers should be Bilstein anyway. The Sport had stiffer dampers over and above the OE Mtech dampers. That and the offset ft wishbone bushes were the extent of the suspension changes - the supposedly thicker ARBs are found on M-tech equipped cars as well as the Sport

[RobM77]

Shropshiremike said:

RobM77 said:

E30M3SE said:

How old are your shock absorbers? Originals still on the car?

Yes, original dampers all round. I started a thread a few months ago on this actually. Previous E36 experience tells me that they need changing soon. I was going to go for the original ones (who am I to differ with millions of pounds of investment and testing at the Nurburgring?), but for about half the price I could get Bilstein replacement suspension all round.

Just as an aside Rob, I noticed in another thread you said your 328 was a Sport? If that's the case the OE dampers should be Bilstein anyway. The Sport had stiffer dampers over and above the OE Mtech dampers. That and the offset ft wishbone bushes were the extent of the suspension changes - the supposedly thicker ARBs are found on M-tech equipped cars as well as the Sport

Yes, that's right, it's a Sport. Hmm I didn't realise that Bilstein made the BMW dampers that went on it. Thing is, I doubt the Bilstein aftermarket kit is the same as they originally made for the car as it lowers it. Not only that, but it lowers the car by a different amount front to back, and I'm not sure why. That seems like a weird thing to do as it'll mess upt he roll centre of the car and how weight transfer effects it. It worries me that it might be done from an aesthetics point of view, which is mainly what puts me off it (it's commonly accepted that the E36 looks a bit odd because the rear arches are filled and the fronts have gaps - this kit changes that). I don't care what the car looks like, I just want it to drive well. I certainly don't want howo to car drives to be effected by aesthetics!!

[dave328]

Following this thread with interest - I have the exact same problem and am desperate to get it sorted.

I've replaced the rear shocks on mine (they had no rebound so was expecting it to be contributing) and it's no better.

My mate/friendly mechanic looked at it a few months ago and seemed to think that it was wear in the steering rack (the car has done 160k) because there was such a large amount of movement, but it doesn't feel like that to me. I've driven cars with knackered racks ( ) and it feels nothing like this.

The more I read about bushes (sorry) the more I think its the cause. With that in mind I'm buying a full Powerflex bush package at the end of the month to see if that sorts it once and for all.

Edited by dave328 on Monday 3rd November 18:44

Edited by dave328 on Monday 3rd November 18:45

[RobM77]

dave328 said:

Following this thread with interest - I have the exact same problem and am desperate to get it sorted.

I've replaced the rear shocks on mine (they had no rebound so was expecting it to be contributing) and it's no better.

My mate/friendly mechanic looked at it a few months ago and seemed to think that it was wear in the steering rack (the car has done 160k) because there was such a large amount of movement, but it doesn't feel like that to me. I've driven cars with knackered racks ( ) and it feels nothing like this.

The more I read about bushes (sorry) the more I think its the cause. With that in mind I'm buying a full Powerflex bush package at the end of the month to see if that sorts it once and for all.

Edited by dave328 on Monday 3rd November 18:44

Edited by dave328 on Monday 3rd November 18:45

Ah - glad to know I'm not the only one. My racing instructor has an E36 and he says it's a design flaw in the front suspension, which he's eradicated somehow. My 325i didn't do it anywhere near as much as my 328i though, so he's probably right (I'm sure he is), but I think my (or our) problems might be just being exacerbated by worn components.

[sniff diesel]

RobM77 said:

...the '98 328i sport runs 245s at the rear, so that could cause it. I don't think the 325i was much more than 200.

205/55 R15 on my 325i

[Shropshiremike]

RobM77 said:

Shropshiremike said:

RobM77 said:

E30M3SE said:

How old are your shock absorbers? Originals still on the car?

Yes, original dampers all round. I started a thread a few months ago on this actually. Previous E36 experience tells me that they need changing soon. I was going to go for the original ones (who am I to differ with millions of pounds of investment and testing at the Nurburgring?), but for about half the price I could get Bilstein replacement suspension all round.

Just as an aside Rob, I noticed in another thread you said your 328 was a Sport? If that's the case the OE dampers should be Bilstein anyway. The Sport had stiffer dampers over and above the OE Mtech dampers. That and the offset ft wishbone bushes were the extent of the suspension changes - the supposedly thicker ARBs are found on M-tech equipped cars as well as the Sport

Yes, that's right, it's a Sport. Hmm I didn't realise that Bilstein made the BMW dampers that went on it. Thing is, I doubt the Bilstein aftermarket kit is the same as they originally made for the car as it lowers it. Not only that, but it lowers the car by a different amount front to back, and I'm not sure why.

If it's like the old Bilstein kits they did they will be Ventura springs. If you want to preserve the OE feel stick with the original BMW spec springs or if you want to go aftermarket go for Eibach or H&R imo

[SJobson]

How many weights are there on your alloys? My E39 wheels balanced OK on the tyre-fitters machines, but with quite a few weights. After going through a pothole a week ago and obviously bending one, I wondered how round the others were. Turns out they weren't... A new set of alloys has cured the wandering and lumpy ride. It really is uncanny, and I wish I'd replaced the wheels before doing all the bushes, wheel bearings etc.

[RobM77]

SJobson said:

How many weights are there on your alloys? My E39 wheels balanced OK on the tyre-fitters machines, but with quite a few weights. After going through a pothole a week ago and obviously bending one, I wondered how round the others were. Turns out they weren't... A new set of alloys has cured the wandering and lumpy ride. It really is uncanny, and I wish I'd replaced the wheels before doing all the bushes, wheel bearings etc.

That's interesting, thanks. I'll have a look when I pick it up from its service tonight.

[Shropshiremike]

RobM77 said:

It's in for a service tomorrow, so I'll ask them to have a general look over.

Did they sort it out for you?

[RobM77]

Shropshiremike said:

RobM77 said:

It's in for a service tomorrow, so I'll ask them to have a general look over.

Did they sort it out for you?

Thanks for asking. The bushes at the back are fine apparently, although (as I've mentioned already), my dampers are a bit worn. They think the main cause is the tyres, and would recommend changing them soon. I'll do that and report back

Good service though, I was really pleased. My throttle body was bunged up apparently. They've cleaned that through and it's improved the pick up from zero throttle, which has made the car smoother to drive. It's also hopefully solved an idling problem I was having - sometimes the car wouldn't idle and the engine would just stop when you declutched to come to a halt.