BMW M5 Forum and M6 Forums banner

1 - 20 of 30 Posts

·
Registered
Joined
·
1,618 Posts
Discussion Starter #1
I've been noticing more and more tracking problems on my car and so I decided to take a closer look. It appears that the rear camber is extremely negative. The inside tread on my rear tires is badly worn, especially on the left (driver) side. I did get my car air-borne once and came down hard on the suspension. Do you think I could have knocked something out of adjustment? Nothing appears broken or bent except one anti-roll bar clamp. :(

I've searched the board and there seems to be conflicting opinion if the rear camber can be adjusted. If it can, does anyone know how? I.e., where is the adjustment done? Pictures would be ideal! :) . I'm trying to decide if I take this to the dealer (I'm out of warranty) or to a local shop to have an alignment done. I'm due to replace the tires, so I want to get this fixed before I mess up another set.

Thanks!
 

·
Registered
Joined
·
3,002 Posts
From the factory the car is recomended from about -1.3 to 2.0 degrees. I'd get that checked...it may just be you dont' need that much, but I woun't go playing with it your self...The rear is adjustable but factory the front is not, if you go after market thats where that comes in, and some negitive camber is a good thing for handling.
 

·
Moderator
Joined
·
10,458 Posts
While I don't have the answer as to how, i do know for sure that the rear camber is adjustable on the e39 chassis. Call a few alignment shops to see if they think it is, my local 'wheel works' had told me there is no adjustment possible, front or rear, so i don't go there! (i should have asked why a "bmw alignment" costs more, since there's less to do!)
 

·
Registered
Joined
·
3,002 Posts
mottati said:
While I don't have the answer as to how, i do know for sure that the rear camber is adjustable on the e39 chassis. Call a few alignment shops to see if they think it is, my local 'wheel works' had told me there is no adjustment possible, front or rear, so i don't go there! (i should have asked why a "bmw alignment" costs more, since there's less to do!)
Bmw uses sand bags or somthing like that to acount for passenger weight, plus it's bmw thats why it cost more.
 

·
Registered
Joined
·
1,618 Posts
Discussion Starter #6
I wonder if the problem isn't camber, but I knocked something else out of alignment. Would this likely be fixable by getting a re-alignment, or should I have the dealer look at it for other problems?
 

·
Registered
Joined
·
590 Posts
PhilSeastrand said:
I've been noticing more and more tracking problems on my car and so I decided to take a closer look. It appears that the rear camber is extremely negative. The inside tread on my rear tires is badly worn, especially on the left (driver) side. I did get my car air-borne once and came down hard on the suspension. Do you think I could have knocked something out of adjustment? Nothing appears broken or bent except one anti-roll bar clamp.
Phil from the sound of it you knocked the rear toe-in out. If both rear tires are wearing on the inside your rear wheels are toed-out, meaning the front of the tire is facing outward. I'm sure it's adjustable, but you probably bent something when you jumped the car.

Usually the rear toe is set at an eight inch toe-in. Yours is probably ¼" to ½" toed out. That's a big dfference. You should get it check out be someone who will take a good look at the rear suspension to make sure nothings bent.


Joe
 

·
Registered
Joined
·
4,515 Posts
hudson said:
Phil from the sound of it you knocked the rear toe-in out. If both rear tires are wearing on the inside your rear wheels are toed-out, meaning the front of the tire is facing outward. I'm sure it's adjustable, but you probably bent something when you jumped the car.

Usually the rear toe is set at an eight inch toe-in. Yours is probably ¼" to ½" toed out. That's a big dfference. You should get it check out be someone who will take a good look at the rear suspension to make sure nothings bent.


Joe
The control arms are fairly close together on the E39. This means that slight settling/distortion of the rubber bushings used in the suspension joints will cause neg camber to increase as these cars age. Occasional alignment tweaks and/or bushing replacement will restore original settings. I have noticed the aging, higher mile E39 5xxi fleet ('97-'99) is already requiring rear suspension bushing replacements. It'll be M5's next, since they share these rubber parts.

The problem could indeed be a toe out condition as mentioned above, as this will cause weird handling and severe inner tire wear. I'm just offering another possibility.

Toe out will wear both rear tires in the same fashion. If one bushing is bad and causing excessive neg camber on one side, only that tire will show inner tire wear. If both tires have excessive neg camber, the tire wear will look like excessive toe out...but handling will not suffer.
 

·
Registered
Joined
·
590 Posts
Lscman said:
The control arms are fairly close together on the E39. This means that slight settling/distortion of the rubber bushings used in the suspension joints will cause neg camber to increase as these cars age. Occasional alignment tweaks and/or bushing replacement will restore original settings. I have noticed the aging, higher mile E39 5xxi fleet ('97-'99) is already requiring rear suspension bushing replacements. It'll be M5's next, since they share these rubber parts.

The problem could indeed be a toe out condition as mentioned above, as this will cause weird handling and severe inner tire wear. I'm just offering another possibility.

Toe out will wear both rear tires in the same fashion. If one bushing is bad and causing excessive neg camber on one side, only that tire will show inner tire wear. If both tires have excessive neg camber, the tire wear will look like excessive toe out...but handling will not suffer.
Lscman, Phil mentioned that both rear tires were worn on the inside and the car had some tracking problems it sounds to me like classic rear toe-out problems. Although you are correct in saying worn bushings would cause tire wear problems, not sure if they would make the car handle all that badly.


Phil how many miles on the car?


Joe
 

·
Registered
Joined
·
1,618 Posts
Discussion Starter #10
Thanks for the comments!

I'm at about 36K miles. Both rears are showing wear, but the left rear is significantly worse. I'll try to take pictures tonight and post them.

I visually checked all the rear suspension and didn't see any obvious signs of bent or damaged components. If i did bend something, how could I tell? Since all (most) of the components are cast, I assumed they would break before bending significantly. Is that a bad assumption? Could I have compressed a bushing and thus caused the toe-out problem or do I have to bend something to cause this? If it's adjustable, where is the adjustment made? I couldn't see anything that I would describe as adjustable!

Would a broken anti-roll bar clamp affect this situation? Or would it just affect the body roll in turns?

Would you recommend going to the dealer to assess this or a reputable alignment shop? I'm worried that the dealer will gouge me or the alignment shop won't know about the E39 in detail. Neither option feels good to me! :(

Again, thanks for the feedback.
 

·
Registered
Joined
·
590 Posts
PhilSeastrand said:
Thanks for the comments!

I'm at about 36K miles. Both rears are showing wear, but the left rear is significantly worse. I'll try to take pictures tonight and post them.
It's probably not the bushings but I would check them. It's sounds like what ever happen you'll find it on the left side. When you move the camber the toe moves to, which might account for the most wear on the left and both tires worn on the inside. Any change in camber (moved or bent ) always involves a change in toe.

I visually checked all the rear suspension and didn't see any obvious signs of bent or damaged components. If i did bend something, how could I tell? Since all (most) of the components are cast, I assumed they would break before bending significantly. Is that a bad assumption? Could I have compressed a bushing and thus caused the toe-out problem or do I have to bend something to cause this? If it's adjustable, where is the adjustment made? I couldn't see anything that I would describe as adjustable!
Cast components do bend enough to throw the alignment out significantly. It's hard to tell what's bent sometimes. You have to get the car on a lift and inspect both sides and measure the control arms to compare each side. If something is bent you usually will find it using this approach.

There are eccentric bolts that connect the control arms to the sub frame and thats were the adjustment is. There's one for the camber and one for the toe on both sides.

Would a broken anti-roll bar clamp affect this situation? Or would it just affect the body roll in turns?
It's just effects the body roll. It's not a tire wear item.

Would you recommend going to the dealer to assess this or a reputable alignment shop? I'm worried that the dealer will gouge me or the alignment shop won't know about the E39 in detail. Neither option feels good to me! :(

Again, thanks for the feedback.
The million dollar question. You would think the dealer should know but that's not always the case. A good alignment shop should be able to align the rear end but I'm not sure they understand the suspension on the car. I think the best person to do it is the shop that does high end crash work. They should be able to find the problem, fix it, and align the rear end again.

An easy way to check the toe is with a tape rule. Measure the width across the front of the tires then measure the width across the rear of the tires. If they are equal you have 0 toe. If it's more in the front it's toed out, if it's less in the front it's toed in. You should be 0 to 1/8" toe-in.

Hope this helps cherrsagai
Joe
 

·
Registered
Joined
·
4,515 Posts
hudson said:
Lscman, Phil mentioned that both rear tires were worn on the inside and the car had some tracking problems it sounds to me like classic rear toe-out problems. Although you are correct in saying worn bushings would cause tire wear problems, not sure if they would make the car handle all that badly.


Phil how many miles on the car?


Joe
I fully concur that the symptoms (inner tire wear with poor handling) are "classic" for a rear toe out condition. The question is why! Aside from: 1) frame damage from a wreck or 2) radical ride height changes due to suspension mods, I think bushing condition is the primary cause for changes in alignment & tire wear.

As I indicated, a car with good toe but too much neg camber from distorted, healthy bushings will handle very good. Be advised though that worn or torn control arm bushings will cause wildly dynamic toe changes as the wheel(s) flop around instead of maintaining intended geometry/alignment. This results in very quirky handling and weird tire wear. I'm just offering other possibilities (bad control arm bushings) to cover all bases, since bad rear bushings is a known problem with E39. The rubber bushings can dryrot just sitting idle for a couple years, so condition varies wildly and it's seldom a function of mileage or duty. Ozone and pollution attacks rubber & history shows that rubber quality varies by batch/lot. I've seen bushings crack & turn to dust on one side of a vehicle while others of the same age and type remain fresh.

Root cause analysis is the only answer. Realignment for odd tire wear patterns without a thorough bushing inspection is not prudent.
 

·
Registered
Joined
·
590 Posts
PhilSeastrand said:
I did get my car air-borne once and came down hard on the suspension. Do you think I could have knocked something out of adjustment? Nothing appears broken or bent except one anti-roll bar clamp.
Lscman, this may be a clue.
Joe
 

·
Registered
Joined
·
4,515 Posts
hudson said:
Lscman, this may be a clue.
Joe
True...I did read that. I am not clear if the tire wear pattern changed over night. Did the last set of tires wear straight? How long ago? The Dukes of Hazard event may or may not have caused the problem....sounds a bit like a worst case doomsday scenerio. The tires may have been wearing on the inside all along; this seldom becomes apparent until wear patterns develop after many miles rack up and/or concern is raised due to a memorable event. Badly cupped and/or worn tires do not track well, so this handling issue may be a chicken or the egg situation. The apparent alignment problem also does not tell us if something got bent or a bushing was damaged/torn or an alignment point slipped. I think root cause is important to understand wrt which hardware was affected & what is it's current condition.

It is easy to check bushings...especially knowing that E39's are experiencing this failure mode. Blindly trying to realign the car is one option. I've seen this approach taken many times on cars with bad bushings...including my wife's old Sunbird (in 1988). After tire wear and noises continued, inspection showed it had no rubber bushing left in the lower control arms! This quickie alignment approach is very common and it never works. This is a moneymaker; an alignment tech is naturally discouraged from pointing out such problems because the customer seldom wants to cover the diagnostic labor...knowing a realignment is needed (again) after repair. I've also seen alignments done to compensate for bent parts. This can effectively compensate for minor damage, but fresh, straight parts are always preferred. I would personally want these precautionary steps taken on a $5K commuter car that has seen abuse or wear. I never get an alignment to address tire wear problems without investigating the source of the problem.

It's quite another thing to verify the straightness of a BMW frame assembly. The typical local frame shop may struggle to properly jig an E39 to check for straightness. Hopefully the frame &/or control arms are not bent.
 

·
Registered
Joined
·
1,618 Posts
Discussion Starter #15
I would have to say that the wear pattern changed after the 'incident'. The first set of tires wore perfectly and the current set (second set) were wearing good at the beginning. I would have to say that I must of either bent something or knocked it out of alignment. I'll take some measurements and see what I find.

It strikes me that a hard landing would mostly impact the strut and not the control arms since they don't bear weight. I could see if I hit sideways a control arm could be bent, but just a downward force?

Can I visibly inspect the bushings without removing anything (other than the tire)?

I'm also assuming a good alignment shop can tell me what the current toe-in is, and if they can adjust it back to specs.

Thanks again for your comments. I think I'm getting a picture in my mind about what I have to do. As usual, this site comes through again!
 

·
Registered
Joined
·
4,515 Posts
PhilSeastrand said:
I would have to say that the wear pattern changed after the 'incident'. The first set of tires wore perfectly and the current set (second set) were wearing good at the beginning. I would have to say that I must of either bent something or knocked it out of alignment. I'll take some measurements and see what I find.

It strikes me that a hard landing would mostly impact the strut and not the control arms since they don't bear weight. I could see if I hit sideways a control arm could be bent, but just a downward force?

Can I visibly inspect the bushings without removing anything (other than the tire)?

I'm also assuming a good alignment shop can tell me what the current toe-in is, and if they can adjust it back to specs.

Thanks again for your comments. I think I'm getting a picture in my mind about what I have to do. As usual, this site comes through again!
The rear suspension utilizes shocks, not struts. Fore-aft positioning (spindle toe) is maintained exclusively by the triangulated control arm assy. The control arms & bushings bear all fore-aft forces that try to alter toe, incl braking and throttle. These forces rise to supercritical levels if the brakes are applied as you land. Boom. This is what removes suspension from huge, sturdy off-road monster trucks that putz around an arena at 40 MPH. Forces will try to force the wheel rearward, which creates toe out if anything "gives". The E39 suspension is not designed for such abuse. Max strength has likely been built-in for hard acceleration. Severe deceleration loads are invariably transferred to the front suspension under hard braking, so the lightweight aluminum E39 rear suspension system (initially designed for a 5er) is not overdutied under normal decel conditions.

"Knocking out of alignment" is a real misnomer as it's extremely rare; that is, alignment bolts rarely rotate or "slip" out of position....especially on an aluminum frame. These bolts grip tenaciously...the tubular frame will likely crack or bend first. If adjustments did "slip", gouge marks should be visible where the aluminum eccentric washer on the control arm adjuster (with it's tiny drilled holes in a row for the alignment tool) was forced to rotate under full bolt torque. When someone states that a car was knocked out of alignment, it typically means the chassis got bent/twisted in some way. Alignment changes are often made to compensate for minor chassis "reshaping".

If the problem is due to this airborne incident, something may be bent or bushings damaged. The bushing is difficult to inspect, but many threads pertaining to this subject exist on 5er forums. An E39 bushing extraction/insertion tool sells for around $200. Some creative folks use alternate methods such as an assortment of big washers, spacers and huge sockets in conjunction with a bunch-o large bolts & nuts.

If you don't want to inspect bushings, a realignment may be worth a try. I am only cautioning you in case handling problems persist....and so you can put your mechanic in the proper frame of mind. He should be looking for problems first.
 

·
Registered
Joined
·
590 Posts
PhilSeastrand said:
I would have to say that the wear pattern changed after the 'incident'. The first set of tires wore perfectly and the current set (second set) were wearing good at the beginning. I would have to say that I must of either bent something or knocked it out of alignment. I'll take some measurements and see what I find.
Phil I think the next step should be checking the rear alignment specs. If you find that the specs are out of range (which you should because of the tire wear) you need to find the "root" of the problem as Lcsman stated. This is the most important step for a correct and long lasting repair. Something moved whether it's a bushing or a bent component. As Lcsmam mentioned pay attention to the bushings because they have a history of failure. It is rare that the alignment "gets knock out" without a little help say from a hard landing. The suspension was made for perfomance not the demolition derby.


Keep us posted
Joe
 

·
Registered
Joined
·
63 Posts
Hi Guys,
Please allow me to add to the very detailed discussion above:
I would agree with Lscman and suggest lower arm ball joint as being 'public enemy No.1'. Before taking your vehicle to the alignment shop I would suggest that you raise the rear of the vehicle and check for movement in these rear joints. It's very simple, just grip the wheel at top and bottom and try to move it inwards/outwards (this will take some effort) any play will indicate lower ball joint or one of two upper link arms. Any movement here would deem alignment useless in it's current state. Fix the play if present and then align vehicle.
If movement is not found a straightforward computer 4 wheel alignment (KDS) will soon locate nature of fault. If toe/camber or caster values do not adjust into uniform tolerance a bent/worn component could be assumed. This could also be confirmed by an SIA indifference of more than 1.5 Deg side to side.
Hope this helps and not confuses?
Best Regards
Peter.
 

·
Registered
Joined
·
590 Posts
M500PMW said:
Hi Guys,
Please allow me to add to the very detailed discussion above:
I would agree with Lscman and suggest lower arm ball joint as being 'public enemy No.1'. Before taking your vehicle to the alignment shop I would suggest that you raise the rear of the vehicle and check for movement in these rear joints. It's very simple, just grip the wheel at top and bottom and try to move it inwards/outwards (this will take some effort) any play will indicate lower ball joint or one of two upper link arms. Any movement here would deem alignment useless in it's current state. Fix the play if present and then align vehicle.
If movement is not found a straightforward computer 4 wheel alignment (KDS) will soon locate nature of fault. If toe/camber or caster values do not adjust into uniform tolerance a bent/worn component could be assumed. This could also be confirmed by an SIA indifference of more than 1.5 Deg side to side.
Hope this helps and not confuses?
Best Regards
Peter.
Peter you are correct in saying that all loose suspension parts, (ball joints, rubber bushings, bent components) should be replaced to make a quality alignment. I would think that if the ball joints and the bushings were worn badly enough to create this type of tire wear you would hear some sort of clunking noise in the rear on directional shifts (example from reverse to forward or left to right). Phil didn't mention any noises in the rear so I'm assuming that it was quiet. I still think the key is that the car may have come down hard on the left side and bent something (ball joint, bushing, control arms, spindle, subframe)

I hope Phil will keep us posted. I love this stuff.


Joe
 

·
Moderator
Joined
·
10,458 Posts
i had a ball joint (drivers side rear) that was worn and was discovered during my suspension upgrade. It made no noise and i really didn't notice anything unusual other than a little sloppiness that I had assumed were worn bushings.
the guys at dinan said this was not uncommon with the e39 m5.
Mike
 
1 - 20 of 30 Posts
Top