Bent spindle?

[deniss]

I've been having an uneven tire wear issue. The outer portion of the left front tire has almost gone bald, while the inner portion of the same tire looks normal and comparable to the right front tire.

I took the car to the MB dealer to get it aligned, and they found that the left wheel won't come in for alignment! From what the service adviser told me, the tech working on the car conferred with shop foreman, and they concluded that this is probably due to a bent spindle and suggested replacing the spindle assy for left front.

The adviser told me that the techs have seen this happen before, from such things as running into a curb while parking or something of that effect. I confess to having had such a parking mishap or two not long ago. They advised me that an alternative would be to take the car to a body shop and have them inspect the frame, but I can attest that the car has not been in any sort of collision.

Can anyone offer any thoughts on whether a bent spindle could in effect be the cause of uneven tire wear that I described?

[jt20]

I would agree that it is possible. Its only aluminum alloy. But certainly check the other components yourself for signs of failed rubber.

I also bent one.

edit: NOT aluminum alloy

[deniss]

Originally Posted by jt20

I would agree that it is possible. Its only aluminum alloy. But certainly check the other components yourself for signs of failed rubber.

I also bent one.

Oh, good to know! Maybe for the reason of absorbing impact.

Are control arms also aluminum alloy, or steel?

[jt20]

I remember rust on my LCA, but the UCA is aluminum alloy as well.

[tobybul]

Originally Posted by jt20

I would agree that it is possible. Its only aluminum alloy. But certainly check the other components yourself for signs of failed rubber.

I also bent one.

Unless we are talking about something different, I think the spindle is made of steel. Isn't it the part that the UCA, the ball joint and the wheel bearing connects to?

[jt20]

the main body that we refer to as 'spindle' is alloy, the actual spindle itself where the bearings go is some form of steel, most likely.

There is a bolt-on steering arm on the bottom that may be steel as well.

Have you done your ball joints yet?

[deniss]

Originally Posted by jt20

Have you done your ball joints yet?

Yes, balljoints are in good state of repair. I inspect the car periodically, and the techs also inspected entire front suspension.

I haven't replaced UCAs since I bought the car, but I did check those balljoints and greased them generously when I replaced their dust jackets a while back. Lower balljoints were done sometime in '06, and the techs didn't express any concern over them.

I think the term I used isn't proper: by "spindle" I mean the steering knuckle assy that hooks up to upper and lower balljoints. I believe that's what the techs are referring to... From vague recollection of the parts catalogue, I think this assy is one solid unit, right?

[jt20]

I think we all understand those terms to be interchangeable on these vehicles.

correct, mostly one piece.

[Diesel911]

[QUOTE=deniss;2327421]Yes, balljoints are in good state of repair. I inspect the car periodically, and the techs also inspected entire front suspension.

I do not think what they are saying is entirely logical.
I was going about 45 and managed to drive over an 3-4 inch tall Traffic Island.

I hit it hard enough that it severely dented the Driver side Aluminum Rim and the Driver side Rear Rim and cracked the Rear Swing Arm.
After I replaced the 2 Rims and put on a used Rear Swing Arm I drove the Car with no obvious problems.

About 1 year after that over a 3 day period my Front Wheels developed an obvious slant and I started getting (I cannot remember which) inner or outer tire wear on both front Wheels.

It was my Lower Control Arm Bushing and 1 Upper Control Arm Ball Joint was also shot.

The above leads up to the fact that hitting the Island did not bend my Spindle. Next, unless your LCA and UCA Bushings are extremely bad to the point there is a lot of play in them you cannot see what is wrong with them.

The solid rubber separates internally; see Pic. I shoved Tooth Picks in the where the rubber seperated.

If you remove the Steering Knuckle/Spindel the Dealer is supposed to have a tool- Inspection Tool For Steering Knuckle 116 589 05 23 00

[DeliveryValve]

Could it be possible that the tech does not know how to align w123? Most alignment shops will not touch the guide rod. Will only touch the eccentric bolt and tie rods.


.

[rrgrassi]

Originally Posted by DeliveryValve

Could it be possible that the tech does not know how to align w123? Most alignment shops will not touch the guide rod. Will only touch the eccentric bolt and tie rods.


.

This car is a w126. IIRC, it aligns a bit different than the w123.

Wouldn't a bent steering knuckle also affect the tie rods and toe in/out?

[jt20]

^ there are some slightly different parts, but the set up is the same. I used a spindle from a w126 on my 123.. identical, even the steering arm.


-- Diesel911 has a good point about the rubber and that you don't go bending spindles every time you mess up your parallel parking job. These chassis are built strong and my car was in a pretty bad accident to bend that spindle.

...but keep in mind there are 2 types of forces here. The radial force (perpendicular to the tire tread and absorbed by the shocks) and the axial force (along the axis of the spindle with no shock absorption). You need to make that call if the latter force has occurred and in what severity. ( ie.. if they are trying to sell you a new spindle... get the hell outta there.)

[deniss]

Originally Posted by DeliveryValve

Could it be possible that the tech does not know how to align w123? Most alignment shops will not touch the guide rod. Will only touch the eccentric bolt and tie rods.

I don't believe they touched caster struts (or, guide rods) - they were aligning with tie rods, as I asked the service adviser that. They've aligned my car very well before, but this developed over last several months.

Originally Posted by Diesel911

About 1 year after that over a 3 day period my Front Wheels developed an obvious slant and I started getting (I cannot remember which) inner or outer tire wear on both front Wheels.

It was my Lower Control Arm Bushing and 1 Upper Control Arm Ball Joint was also shot.

I believe you would have had the inner tire wear if the bushings or the balljoints were shot.

The weight of the car plus the spring keep the lower control arm in tension and the upper control arm in compression. If the lower rubber is worn, that would make the bottom of the spindle angle out and cause inner wear. If the upper rubber is bad, the UCA would be pushed inward by compression, making the top of the spindle angle in and again cause inner tire wear.

In your case, what probably happened is that the rubber bushing(s) must have just cracked, which would explain such sudden deterioration.

In my case, it appears that the tire wear works against gravity, so to say. For the outer tire wear to happen, the top of the spindle has to protrude out, which could have happened if I rolled onto the curb with the wheels turned in/out off center.

I believe time scale of the event might make a difference in how the impact is channeled, also. Yours was a very sudden jolt, while mine was a more prolonged roll. I don't know how exactly dynamics would work out, but I am just pointing out that you and I may be comparing apples and oranges.

[deniss]

Originally Posted by jt20

...but keep in mind there are 2 types of forces here. The radial force (perpendicular to the tire tread and absorbed by the shocks) and the axial force (along the axis of the spindle with no shock absorption). You need to make that call if the latter force has occurred and in what severity. ( ie.. if they are trying to sell you a new spindle... get the hell outta there.)

I think if they were trying to sell me, they would probably tell me that both control arms and/or balljoints need to be replaced - especially since they don't have a record of them being replaced, and I have no idea when they or their rubber was replaced. Yet, they told me that both balljoints are fine and that both control arms are fine and that the rubber is in good condition.

I'm guessing that the wheels not coming into alignment indicates that toe-out is excessive, which probably would not happen if something like an idler arm was bent... I think if any steering components were wrong, they would have told me. So my guess is that either the steering knuckle did somehow get bent (hopefully!) or I have a bent frame somewhere (I hope not!). Oh how I hope that it isn't the latter...

[jt20]

they didn't tell you which parameter was not correctable?


...there are many available threads on the tie rods for adjustment; it is hard to imagine that they could not correct the toe