Wear on guide rod? - PeachParts Mercedes-Benz Forum

origamitect · #1 06-05-2006, 03:34 PM

So after I get Frau Frankenbenz back from the great transmission adventure, I notice that when I make a normal u-turn (to the left), it sounds like something is grating on something else. I took a peek under the passenger fender, and it appears that what I think is the guide rod (not sure of all the names of the suspension parts under there...) clearly has a shiny spot where all the dark gunk has worn away. I know absolutely nothing about how the front suspension works on this car, so if anyone has a guess on what could cause this, please be as simplistic as possible. I looked at the front suspension diagram at the performance parts site,
http://www.performanceproducts4benz.com/Drawings.aspx?bmid=160

but it didn't make much sense to me. If there is another diagram out there that isn't exploded, could someone point me in that direction? Thanks in advance for your help.

(p.s.) as if I don't have enough mercedes repair fun, my husband and I are purchasing our neighbor's 300D as a second car. Now we can rotate which one is in the garage at any given time

origamitect · #2 06-06-2006, 12:17 AM

bump. anyone?

SD Blue · #3 06-06-2006, 10:00 AM

I'm not completely familiar with the W123 chassis suspension, but from studying the diagrams it sounds like your tire is rubbing the guide rod. Is this possible?

If so, your car may need an alignment. I couldn't imagine, from your description, what else could be the culprit. But I also can't imagine a car being this far out on alignment.

It would have to be adjusted nearly all the way to one side.

origamitect · #4 06-06-2006, 01:33 PM

Wouldn't I see some kind of wierd wear on the tires if there was an alignment issue that severe? The car had new tires on it when I bought it 2 years ago, and there doesn't seem to be any uneven wear that I can notice. The car has shocks installed new 1 year ago. I did notice today some groaning when I was pulling into the parking lot at work.

mybenz123 · #5 06-06-2006, 01:56 PM

One way to know for sure is to move the steering
wheel all the way to the left(as if turning) and
see where and what is touching.

I don't know if this happened all of a sudden or that
you have had this problem for some time.
If it is sudden then most likely something failed
and is causing those parts to rub.

Besides the conclusion from SDblue.
These could also be the cause.

1)Guide rod mount (#22 in diagram)hardware missing, worn, loose
or broken. This might make the rod loose enough to hit the
tire when turning.

2)Worn,loose or broken track rod mount(#20 in diagram)
This might not create enough sideways movement but one
never knows.

3)Bent or loose guide rod(#21 in diagram).

Checking for missing parts is easy enough.
Checking for worn or loose parts is a little more
involved but should be no problem.

Just raise the front of the car.
Put the car on jack stands and with a breaker bar
or really big screwdriver try
to move all the parts involved.
If any of them is loose or has exesive movement in it
then you have found the problem.

Hope this helps.

Louis.

SD Blue · #6 06-06-2006, 02:13 PM

I went back and read the description in your thread. I'm not sure what the shiny spot is and that is why the questions.

This sounds more like low power steering fluid than anything else. Also check to see (color) if the power steering filter needs replacement.

rs899 · #7 06-06-2006, 02:54 PM

I have had a shiny spot worn on my guide rods by the brake pad sensor wire- you might check that.

origamitect · #8 06-07-2006, 10:12 AM

Thank you all for your responses so far. I'll jack it up this weekend and take a look - planning on doing the front wheel bearings anyway. I looked again and it is clear that the front edge of the tire is rubbing against part of the fender in extreme turn situations. (rubber mark on the fender @ contact point) The power steering pump isn't whining - I know that sound from a different car (although I'm sure its due a flush and new filter). The tires are not over-sized - is the fact it can touch the fender in a quick tight turn evidence of anything obviously wrong? Or does this just happen? The brake sensor wire thing is interesting - my brake sensor light just started lighting up when I brake a couple of days ago.
Another dumb question - does the track rod mount attach to the body? Thanks for your help and your patience...

SD Blue · #9 06-07-2006, 11:23 AM

Yes, since you are running stock size tires there should be no rubbing anywhere. Sounds as if the alignment is way off center. When you have the wheels pointed dead ahead, Is the pitman arm pointed straight ahead? (This is the short arm attached to the bottom of the steering box shaft and connected to the track rods)

The guide rod attaches to the spindle and the other end attaches to a mount that is part of a subassembly attached to the body.