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-   -   Steering wheel shake after FCAB replacement (http://forum.e46fanatics.com/showthread.php?t=940542)

LeMansteve 08-24-2012 09:46 AM

Steering wheel shake after FCAB replacement
 
I thought I would start a thread to document my adventures in replacing original suspension components on a high-mileage car. Earlier this week my brake pad light lit up and I brought my car to a local independent specialist to check it out. I would have checked myself and done the job myself but it's not allowed in my townhome complex. :thumbdwn: I'm pretty busy outside of work so its also pretty hard to get to a friend's garage to work on my car. Car has 126k miles with original brake and suspension components. Please dont flame! I plan on slowly replacing everything soon.

They said the rear pad sensor had tripped. I had them replace the rear rotors and pads, brake fluid and fuel filter. He recommended replacing FCABs and the rear diff mount. I had him replace the FCABs only.

I can definitely feel a difference with the new FCABs, but now I am getting a moderate shake in the steering wheel between 60-70mph. I had shake before, but not nearly as much as now. The range of steering wheel shake is about 1/2", observed at the outside of the rim. It comes and goes and is hard to diagnose. About all I can say is it seems to happen easiest when I accelerate through 60mph uphill.

I plan on taking it back to the shop to get a diagnosis. I don't know if they screwed something up when they installed the FCABs onto the original CAs, or if the other old suspension components are now being subjected to more of the suspension movement. Hopefully it is something as simple as an out of balance wheel.

Jools 08-24-2012 09:52 AM

Was an alignment done after replacing the FCABs? I just did mine about a week ago on my '03 330 at 72k miles and the end result was a pretty severe steering wheel vibration at around 65-75mph. Had an alignment done the next day at the recommendation of a friend and now everything is perfectly smooth.

Mango 08-24-2012 10:07 AM

Alignment has absolutely nothing to do with vibration. Nothing.

Your wheels simply need to be balanced by properly calibrated/operating equipment. Look for a road force balance by a machine made by Hunter (IIRC). It's possible your old worn CABs hid this vibration.

ThatGuy_JZ 08-24-2012 10:25 AM

I still say it's your tires. Think about how before you replaced your bushings, those tires were moving around a lot more and wearing in a bad way. Now your bushings are fresh and stiff and it's amplifying the bad wear on your tires. They could be cupped or have flat spots, ect. I had the same issue after doing my FCABs, and after putting on new tires it went away completely. It was most noticeable when the tires were still cold in the mornings. As the tires have worn down over time now, they've lost some of that smoothness, but since they've worn in evenly, I no longer have that vibration.

So, get your tires checked and at least re-balanced if you want. Then just live with it until they wear in or it's time for new tires.

moiz21 08-24-2012 10:45 AM

A similar situation happened with me. I replaced the FCAB's on my car and noticed a shake on the highway. Turned out that the control arms were shot but wasn't as noticeable until I put on the new bushings.

LeMansteve 08-24-2012 11:18 AM

Thanks for the replies, everyone. I had found a few similar posts in a search and planned to start simple. I'll have them check the tires and balancing first. As a few have said, the tires have likely taken a beating on worn shocks and I'm now feeling the irregular wear pattern in the steering wheel.

LeMansteve 08-30-2012 09:14 AM

Update: I swapped the front wheels and runflat tires with 2 from a set I have in storage. The tires on that set are fairly new, non-runflat summer tires. They were mounted and balanced on to repaired M68 wheels (bent rim from a pothole), then put directly into storage about 3 months ago.

The vibration between 60-70mph is 90% gone, but I am still getting some intermittent mild vibration at around 70-75mph.

ExitBuddy 08-30-2012 12:04 PM

Quote:

Originally Posted by moiz21 (Post 14677080)
A similar situation happened with me. I replaced the FCAB's on my car and noticed a shake on the highway. Turned out that the control arms were shot but wasn't as noticeable until I put on the new bushings.

Forgive me if this is a total noob question: Is it the control arm itself that goes, or the ball joints attached to the control arm? I am having trouble visualizing how a hunk of metal goes bad, unless it gets bent or damaged.

Zell 08-30-2012 12:10 PM

Just the ball joints. The control arm itself is a big hunk of metal, as you said. Because the ball joints are not replaceable, the whole thing requires replacing. This is why most people go with Meyle HD control arms, since they have replaceable solid ball joints that are extremely stiff.

moiz21 08-30-2012 12:11 PM

Perfectly reasonable question. If you are in an accident or hit something, yes it is totally possible to bend the arm. But no, in my case the ball joints were done.

eksath 10-04-2012 08:56 AM

Quote:

Originally Posted by LeMansteve (Post 14692180)
Update: I swapped the front wheels and runflat tires with 2 from a set I have in storage. The tires on that set are fairly new, non-runflat summer tires. They were mounted and balanced on to repaired M68 wheels (bent rim from a pothole), then put directly into storage about 3 months ago.

The vibration between 60-70mph is 90% gone, but I am still getting some intermittent mild vibration at around 70-75mph.


OK.Thanks for the update and i would appreciate what your current position is. I have something similar.

2002 330CI. Mostly highway driving. 179K miles. Not abused.

I started with a vibration at 80mph. (it has been about 1 month since front control arms/bushing change). Due to this, I had the tires balanced. Now the vibrations are at 60MPH BUT it comes and goes! (just like you mentioned in your original post). Car is going back to mechanic to recheck but i am curious about your outcome or anyone else's input.

Thanks!

LeMansteve 10-04-2012 10:37 AM

Quote:

Originally Posted by eksath (Post 14786912)
OK.Thanks for the update and i would appreciate what your current position is. I have something similar.

2002 330CI. Mostly highway driving. 179K miles. Not abused.

I started with a vibration at 80mph. (it has been about 1 month since front control arms/bushing change). Due to this, I had the tires balanced. Now the vibrations are at 60MPH BUT it comes and goes! (just like you mentioned in your original post). Car is going back to mechanic to recheck but i am curious about your outcome or anyone else's input.

Thanks!

Current position is the same. Planning on getting balance checked this weekend. I am doing a full shock and strut job soon, but I don't expect that to improve the vibrations.

eksath 10-04-2012 10:39 AM

Quote:

Originally Posted by LeMansteve (Post 14787194)
Current position is the same. Planning on getting balance checked this weekend. I am doing a full shock and strut job soon, but I don't expect that to improve the vibrations.

Thanks. I will keep you posted if i get some resolution from my recheck by my trusted mechanic.

RayPooley 10-04-2012 03:00 PM

Quote:

Originally Posted by LeMansteve (Post 14692180)
Update: I swapped the front wheels and runflat tires with 2 from a set I have in storage. The tires on that set are fairly new, non-runflat summer tires. They were mounted and balanced on to repaired M68 wheels (bent rim from a pothole), then put directly into storage about 3 months ago.

The vibration between 60-70mph is 90% gone, but I am still getting some intermittent mild vibration at around 70-75mph.

The thing with the front end assembly on all cars is that everything wears at the same time but not at the same rate. The rubber components usually wear faster than the metal ones because they suffer from environmental factors as well as load factors. The properties of the rubber deteriorates and they become less able to cope with the run time forces. When the FCABs deteriorate the rest of the components are free to move considerably more than they should and suffer additional stresses and strains due to the change in geometry under load conditions so wear rate increases on everything, including the tyres which are an important part of the geometry. So replacing the FCABs is the first step to restoring the nomonal design geometry. An alignment might be able to complete the restoration of geometry and eleminate the wobble you are experiencing but you have to understand that, if track rod ends and other moving components are worn, nominal design geometry might not be achievable until they are replaced. Wobble is normally associated with geometry issues. Vibration is more likely to be wheel balancing. It is easy to confuse the two though.

LeMansteve 10-04-2012 03:30 PM

Quote:

Originally Posted by RayPooley (Post 14788111)
The thing with the front end assembly on all cars is that everything wears at the same time but not at the same rate. The rubber components usually wear faster than the metal ones because they suffer from environmental factors as well as load factors. The properties of the rubber deteriorates and they become less able to cope with the run time forces. When the FCABs deteriorate the rest of the components are free to move considerably more than they should and suffer additional stresses and strains due to the change in geometry under load conditions so wear rate increases on everything, including the tyres which are an important part of the geometry. So replacing the FCABs is the first step to restoring the nomonal design geometry. An alignment might be able to complete the restoration of geometry and eleminate the wobble you are experiencing but you have to understand that, if track rod ends and other moving components are worn, nominal design geometry might not be achievable until they are replaced. Wobble is normally associated with geometry issues. Vibration is more likely to be wheel balancing. It is easy to confuse the two though.

Thank you Ray. Do you think that worn front struts or strut mounts could be contributing to either the wobble or the speed-sensitive vibrations?

RayPooley 10-04-2012 03:33 PM

Quote:

Originally Posted by LeMansteve (Post 14788216)
Thank you Ray. Do you think that worn front struts or strut mounts could be contributing to either the wobble or the speed-sensitive vibrations?

Yes. The struts and the supporting framework are, after all, part of the geometry. If a spring were to fail on one side, for example, you wouldn't expect to be able to steer it properly.

LeMansteve 10-06-2012 07:40 AM

Update: just returned from the tire shop. I asked them to re-balance all 4 tires due to the vibrations I was getting. They did a visual inspection and noted the tires looked fine with no irregular wear. After a short test drive at 60mph, I'd say 80-90% of the vibration is now gone! I'll give it another week under various conditions to really be confident.

RayPooley 10-06-2012 08:57 AM

Quote:

Originally Posted by LeMansteve (Post 14792763)
Update: just returned from the tire shop. I asked them to re-balance all 4 tires due to the vibrations I was getting. They did a visual inspection and noted the tires looked fine with no irregular wear. After a short test drive at 60mph, I'd say 80-90% of the vibration is now gone! I'll give it another week under various conditions to really be confident.

Trouble with these things is that it only takes another damn pot hole to knock a balance weight off or shift a tire on the rim and you are back to square one. PITA.

LeMansteve 10-06-2012 10:39 AM

Quote:

Originally Posted by RayPooley (Post 14792822)
Trouble with these things is that it only takes another damn pot hole to knock a balance weight off or shift a tire on the rim and you are back to square one. PITA.

My long daily commute doesn't help things either (55 miles each way). It is mostly highway driving so any impact with potholes is pretty sharp. Luckily, the first 10 miles of the commute have just been re-paved!

RayPooley 10-06-2012 12:49 PM

Quote:

Originally Posted by LeMansteve (Post 14792949)
My long daily commute doesn't help things either (55 miles each way). It is mostly highway driving so any impact with potholes is pretty sharp. Luckily, the first 10 miles of the commute have just been re-paved!

Our roads in teh Uk are ferkin terrible. Collectively the UK driver pays about 40Billion in motoring taxes every year and only 4Billion gets spent on the road network. The rest goes into the government's pot to pay foreign and home grown deadbeats to sit on their lazy arses and breed. That's what happens when you let the socialists get a grip. They pay the dead beats to vote for them.


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