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Please help me in diagnosing the subframe bushings and main rear control arm bushing.
I am changing the rear spring and while am at it i am taking at a look of whatever surprises i may find.
I can see that there is a crack in them, not sure if they are supposed to give in like this.
At lease they don't drop down by themselves, so no danger yet.
Car seems to be a bit loose from the rear. Link and bushings seem fine, on the vibration stand.
There is no loud thump when going from engine brake to hard acceleration.
However steering wheel turns to the right side while engine braking, keeps straight when accelerating hard.
Had an alignment, was all ok.
Front is all solid, new bushings, tight ball joints, new shocks and springs, top mounts in great shape, no steering play.
What do you think?
Are these subframe bushings bad?
How about the control arm bushing?
What is the rear toe on your alignment spec sheet?
Are all your tire pressures correct? What are the conditions of the tires?
What is the condition of the brakes? Are they wearing evenly?
those bushings appear to be fine to me but I can't physically touch or see them.
If i'm not mistaken the alignment specs on these w211's aren't exactly dead even/straight. I feel like there is a discrepancy because of someone being in the drivers seat.
I hold the steering wheel straight when I brake. How are you braking the vehicle? And is your vehicle lowered?
Michelin primacy 3 tires, 10kkm one pair, 5kkm on the other. 225 55 16
conti 205 60 16 for winter, old tires, evenly weared.
Does the same regardless of the set of wheels. It seems that with wider tires it pulls harder, but not 100% sure on this.
The car did this after the alignment. Before i had one bad front control arm bushing so it was irrelevant.
Tires are not the problem, almost same behavior.
Brakes are good, evenly weared, front is completely rebuilt, new gaskets, DOT compatible grease, silicone grease on the slider pins, etc.
Rear will follow as soon as the pads will wear out.
Temperature is the same on all disks, no major differences between disks, in both hard braking or no braking driving styles.
Car was lowered due to sagged old springs. Alignment is taken with the old springs.
One broke this winter, so new springs and shocks. Elegance trim, so car sits with the wheel arches about 2-3 fingers above the wheel.
Also installed new main arm bushings, anti roll bar balljoints and bushings. All other balljoints were very solid.
Behaviour was the same after the change. Funny thing was that rear left spring broke right after i lowered the car after i have changed the front suspension.
Crappy quality!
Alignment numbers are taken with camber bolts installed, as the camber was too negative.
These are taken last spring with sagged springs. Will make a new alignment one month after i will finish installing the rear springs.
Managed to change one, will have to do the other.
Springs take a about a week to settle in, at least in front.
Till then i did a rudimentary alignment using two laminated chipboards with grease between them and measured toe using a marked rod.
When braking the steering wheel is dead even, it corrects itself. Same for hard acceleration (eg. 3rd - gas pedal floored).
But when engine braking, or mild acceleration the wheel turns right and pull the car towards the right side.
It only puls if the road has a bit of curvature. If i going on the wrong lane, on the wrong way, where the curvature is towards the other side, car stops pulling, or it pulls to the left.
No play in the wheel of course, any slight turn of the wheel has an effect.
And Repeating myself, new springs and 3cm higher ride height and one broker left rear spring did not had a major influence in this behavior.
I drove other w211, w221 and other mercedeses, they don;t exhibit the same behavior.
the culprit might be that i have two style bushings in the front control arms. See the pics.
However i don't see how front bushings will change behaviour between acceleration and engine braking.
That's why i am suspecting the rear.
Since i am changing the springs and disassembling the rear, i can do more checks.
Will start the other rear spring next week, probably.
All bushings were tested fine at the annual inspection on the vibration stand. I have told them to insist on the bushing check, all was fine but i still have some doubts.
Will revert with new video as soon as i will start working on the right side rear spring.
In theory it's natural for vehicle to pull to right as it's going to naturally pull the side with least resistance. Crown of the road is in the center of the road, so by default pull to right may be normal....
Yes, i am aware of that but right pulling is too extreme for that case.
Since it stops during acceleration or braking it is definitely a problem.
I driven other w211, they don't drive like this.
Also tried manually toe-ing in or out, no major difference.
Currently i don't see how hard acceleration could influence the front suspension.
That's why i think the problem is on the rear.
Well you don't have a lsd or lockers, so one tire fire may cause vehicle to pull under hard accell. I think the right rear wheel is the one that applys the power to the road, may be left rear idk. However have you inspected your differential mount/bushing?
Not sure how to inspect it, besides looking at it.
Will take a look next time i change the other rear spring.
I've just finished changing the broken spring, removing rust from the brakeline, cleaning rust spots and paint them.
A lot of work on this s**tty car.
I am far from that scenario you are describing.
I have a E240, no wheel spin at all, even in 1st gear. I only have 240Nm / 170hp in high rpms, ~100hp at 3000.
With RWD, no wheel spin, maybe with crappy tires.
So hard acceleration is not that hard as you think. But it might be enough to shift the subframe a bit, or some bushings.
Also tried leaving it in neutral, it does not pull.
Did some diy alignment using this method for the front. http://mercedes-diy-alignment.blogspot.ro/
Targeted for under 1mm toe in.
It pulls a lot less and now i am rolling with 225 55 16 summer tires in front and it pulls only on engine braking.
I have to do this for the rear as well, i have measured that rear is toe-in more than 1mm, but specs are 20' there.
Also the rear of the car jumps around on when hitting potholes. Even when going straight.
Like someone would bend the tire and pulls the car to the side.
Is this normal?
Similar when you run too much toe in on the front, and car jumps to the side on potholes. (in case you experienced that)
And since with this piece of s**t car things are never over, rear started vibrating, although it was fine three weeks ago.
Cars seems to be handling ok.
Left shock was still very hard to push in, when changing the spring i had to push it with a jack so it is definitely not blown, but definitely not new.
Car does not bounce on the road, does not squat during acceleration.
It jumps sideways even when going straight and hitting specific potholes or irregularities.
But you have to hit it in a specific angle, it does not always jump.
Anyway, will update after spring change and full alignment. I will definitely try and feel how the right shock is when pushing by hand.
Hopefully i will get it done today.
I am curious on how the other frame bushing looks like.
I already lost my patience with this car. And i still have a rattling chain to change.
my 211 wiggles too when i hit potholes. I try and avoid them as best as possible. My issue is bump steer though because I'm lowered. Hope it rides better for ya!
That is exactly what i was referring to but i did not find the proper words.
Bump steer, but from the rear, front is very solid, as it was completely rebuilt.
Rear wheels look a little with too much camber, almost bmw-like, although ride height is OK. I can fit two fingers between the wheel and the arch.
Front is the same, however i kept the camber bolts in the -4mm position so i might be with 0 camber. (Aligment will fix this, no need for me to do their job)
What could be the culprit?
Upper Camber arms have new bushings and the lower control arm has it's big bushing solid. Nothing on vibration stand.
The arms are the original ones.
Nothing is bent, since both wheels are symetrical so they can't be both bent the same way.
I will revert after the alignment with the values so we don't have to speculate.
Meanwhile, whatever ideas you might have, are welcome, and i will gladly test.
Why do you say that lowering the car causes bumpsteer?
Too much toe or camber?
Also keep in mind that by potholes i don;t mean lunar crater like potholes.
It just has to be at the right angle, on the right wheel, and the car would jump.
That is exactly what i was referring to but i did not find the proper words.
Bump steer, but from the rear, front is very solid, as it was completely rebuilt.
Rear wheels look a little with too much camber, almost bmw-like, although ride height is OK. I can fit two fingers between the wheel and the arch.
Front is the same, however i kept the camber bolts in the -4mm position so i might be with 0 camber. (Aligment will fix this, no need for me to do their job)
What could be the culprit?
Upper Camber arms have new bushings and the lower control arm has it's big bushing solid. Nothing on vibration stand.
The arms are the original ones.
Nothing is bent, since both wheels are symetrical so they can't be both bent the same way.
I will revert after the alignment with the values so we don't have to speculate.
Meanwhile, whatever ideas you might have, are welcome, and i will gladly test.
Why do you say that lowering the car causes bumpsteer?
Too much toe or camber?
Also keep in mind that by potholes i don;t mean lunar crater like potholes.
It just has to be at the right angle, on the right wheel, and the car would jump.
Bump steer is the effect on the suspension when you ride over uneven road surfaces or hit potholes that cause excessive suspension travel. Your's shouldn't be that extreme seeing as you do not have your car lowered. Your explanation sounds somewhat normal to me. the only thing I could suggest, even though you state they are fine, would be to replace rear shocks since you have new springs installed.
every vehicle has some bumpsteer. but the lower you are the worse it is unless you have adjustable dampening, adjustable spring link/thrust arm bushings and adjustable rear camber arms. a normal ride height vehicle will have little bump steer because the suspension is engineered to be comfortable at ride height. However when you slam a vehicle you are loading the suspension up even more per-say but in theory you're unloading the bushings/balljoints ect because the pivot points on all the bushings/joints are more level to the ground, if that makes sense...
For instance a thrust arm and spring link arm on a w211 2wd at normal ride height will go through bushings for both of those arms alot sooner than a identical 211 car that is lowered because the arms angles are more extreme at normal ride height, in turn wearing out the bushings at a higher rate primarily because of pivot points. However as you know you sacrifice ride quality when you lower.
My 211.072 has 148k miles. All original airmatic components, spring link bushings and thrust arm bushings. Only new steering/sus. stuff i've installed is lower ball joints and inner and outer tie rods. Everything else is original. Obviously i've replaced engine suspension/trans mounts. However i'd have to say the reason all those components have lasted this long is because of the lack of work my airmatic system has to do, lowered, and also the lack of strain on bushings/joints/arms. I'm also a very ocd driver, i'll avoid a flat piece of paper if i can hahaha
I will say though it may just be my rear diff is going out, or because I've altered the drive-line geometry/driveshaft angle, i do whine in the rear end at 50-60mph. anything less or more its very kitten like.
Thank you for your response! Very interesting conversation and ideas.
If you put too much toe in in the front you will get massive bumpsteer.
At least that's what happend on my car.
Probably wheels are pushing against each other and when one looses contact the car jumps.
Also the steering wheel turns as bit as the wheel left on the ground straightens itself.
Maybe that is what is happening now on the back on my car.
Not sure on your theory.
For example the front is all leveled, front control arms are horizontal. I don't feel that the confort is lost.
Rear upper arms and toe arms are also horizontal.
I think only the main rear control arm and the rear lower thrust arm (not sure on the name for the one towards the front) are at an angle.
And when you hit a pothole when going straight i think the springs and shocks take the main beating.
Bushings are just for guidance and serve as a counter hold for the other end of the lever.
By lever i mean the main control arm with the spring:
- Fixed end big bushing in the subframe at the control arm end
- spring in the middle, being pressed against the car
- mobile end, the wheel, at the other end on the control arm
So bushing it is still taking a beating regardless of the angle. IMHO.
My bushings were also original, one was bad, from the thrust arms.
I have replaced them all due to their low cost since i had all the suspension taken out.
The upper thrust arm from the rear was also exhibiting signs of wear.
Too bad i did not measure the angles with the rear broken springs, front and back.
But from the outside it camber or toe did not look extreme.
Anyway, back to the subject, no luck with the spring yesterday, i hope i will get it done today.
I feel as though angles play a primary role in wearing of bushings. To my understanding that is why when you do suspension work, it's highly recommended to torque whatever you're working on, with vehicle at ride height. IF you torque a thrust arm to spec on a 2 post lift with the vehicle in the air, suspension unloaded, You certainly will see pre mature wear. Been there done that. It's all in opinion/experience though. It's hard to grasp a concept until you have had encounters with it... Is that your 211?
You are right about that.
Bushings need to be tighten in the natural position of the wheel.
Should you have the suspension dramatically lowered then just measure the distance between the center bore and the wheel arch and re tighten the nuts and keep the wheel at the same height using a jack.
I have given more thought on the bushing agle part. I guess if the angle is zero, then the bushing caries all the load of the force (braking or accelerating)
But if it is at an angle like the rear front lower link, then when the force is being applied the car is being pushed forward but also upwards.
I think it will counter the car tendency to squat. a bit. But the bushing will take the force nonetheless.
Direction will vary and the load might be spread on a bigger surface (a bit forward and a bit up) but that's all.
Lowering will just redistribute forces, and yes, it might concentrate too much in one point.
But i guess it is not possible to lower that much.
Yes, that is my ****ty car. Front spring collapsed, only one spring was bearing the load. And then right after, the rear one broke.
Chain is rattling, and i only have 120k miles on the clock, who knows how many for real.
Had original discs on it, so not that many, but still.
BTW, you should inspect the brake lines, the rear ones on mine started to rust, i think debris picked up by the wheel is entering somehow over the cover, at an angle and it grinds the paint away.
Next time when you inspect tires, just pull the cover by hand. Better to prevent..
twisted front old style bushing
broken rear spring, down a long time ago, up, a month ago
tightening position
surprise, just pull the rear wheel cover near the brake hose
Managed to change the other rear spring.
Driven around 700km so around 450miles, and got bad outside shoulder wear on the rear tire.
Rear was jumping around over bumps, so lots of bump steering from the rear.
Keep in mind that car was not experiencing any rear bump steering before the spring change.
Front is fine, no wear, very stable.
Then i changed the bushings from both rear upper arms and this time i've connected first the toe arm and then the lower thrust arm.
(No bushings change in lower thrust arm as their condition was excelent, despite the age)
I still have some old tires on the rear so i don't mind wearing the hell out of them.
Will go to a professional aligment in the end, but first i am curious if it is possible to screw up the rear angles when changing bushings, or reassembling.
Will revert with the results in a month or two. This is a weekend car, not a daily driven one.
Managed to change the other rear spring.
Driven around 700km so around 450miles, and got bad outside shoulder wear on the rear tire.
Rear was jumping around over bumps, so lots of bump steering from the rear.
Keep in mind that car was not experiencing any rear bump steering before the spring change.
Front is fine, no wear, very stable.
Then i changed the bushings from both rear upper arms and this time i've connected first the toe arm and then the lower thrust arm.
(No bushings change in lower thrust arm as their condition was excelent, despite the age)
I still have some old tires on the rear so i don't mind wearing the hell out of them.
Will go to a professional aligment in the end, but first i am curious if it is possible to screw up the rear angles when changing bushings, or reassembling.
Will revert with the results in a month or two. This is a weekend car, not a daily driven one.
YES!!!!! How did you go about changing rear spring? did you lower control arm at center of subframe or at rear spindle?
Your rear end alignment being off will certainly cause bumpsteer issues as well.
Rear spindle, unfortunately. Had to disconnect toe arm, main control arm, front lower arm and caliper.
The other end, towards the subframe had its bolt frozen in the bushing. Probably rust + aluminium sticked to the bolt.
Since the bushing is elastic i could not knock the bolt out or heat it up with the tourch.
Both sides, same problem, so a lot of work.
Funny thing was that i did this twice, partially. One time for the spring (a mechanic did it, as i lost my patience with this car) and then i did it for removing the upper bushings.
First i had lots of bump steering (steering wheel was not moving but rear was jumping around at potholes).
After bushings change all is fine. An or course it was fine also before the spring change.
So you can totally screw up the rear alignment if you change more than an arm.
Oh, and regarding the spindle bushing it is not very ok. The other side was more viscous when moved and less play.
Subframe bushings were the same. So no change yet.
It is not worth doing anyway.
Did an rear alignment with summer tires on all wheels, correct pressure, but imho rear toe is set too high now. 25' toe in.
Car does not pull anymore but i still have some bump steering from the rear but a lot less.
Maybe due to the -2deg camber.
Anyway, rear was also balanced before the adjustment, 4' on each side so not sure why the car was not stable enough.
Will try less toe, as 25' seems to much for me.
Front is all good, but values are wrong.
Wheels are parallel when measured with a marked bar.
They remain parallel when wheels are on sliding pads or when rolling straight to a stop.
Same results in both cases.
Not sure how that technician measured toe out, as they are clearly parallel.
That shop is definitely out of my list.
I;ve put a bit of toe in, ~1mm, steering seems a bit more stable, no bump steering at the front.
I also found out that the rear tires are 20mm more closer to one another that the front ones.
So probably wider tires on the rear would be better but it does not worth the bother.
Who knows what might break next.
I would like to start a DIY alignment thread, what do you think?
Can it be done?
So, alignment specs from above are bogus. I;ve measured rear to using that bar and will the car rolling to a stop.
I had over 6mm toe in, so over one degree. A lot.
That was the source for bump steering.
Wheels are spread now to 2.5mm so around 20-25', within specs.
The difference is huge. No bump steer and wear is good for the last 2000miles - 3000 km.
Update:
Done over 10kkm / 6000miles and some experiments. Acceptable tire wear till now.
Rear toe between 1.5-2mm (12'-16') works best.
At 2.5mm-3mm (20'-25') exhibits a bit of bump steer.
Tried also almost 0 toe on rear, works fine but i am afraid of inside tire wear due to toe out during acceleration.
No bump steer though.
Rear camber is -2 deg.
Front is -1.5deg / -1 deg 30' camber, toe around 10'.
Wear is perfect on these wheels.
I will definitely not be changing the subframe bushings as performance is acceptable.
Car still has a slight right pull due to road crown, but will try solving this with caster increase on the right side next year.
No luck with the right caster increase, the car still pulls on unflat roads.
I've experimented several setups but 6-16' toe in for the rear works best.
I have over 15kkm / 10k miles with this setup and the wear is fine. 1mm difference from outside to inside which is more than acceptable with -2deg camber!
The tires were not rotated, they were rolled only on the rear axle!
Also lowered suspension should NOT cause bump steer.
I played with another w211 that was lowered - wheels almost at the wheel arch and with little toe in there is absolutely no bump steer and the car is definitely NOT jumping sideways over potholes and other road irregularities.
Works the same with 16 or 18 wheels.
04-20-2018, 07:12 PM
