How do you know if your guide rod bushings are bad? - PeachParts Mercedes-Benz Forum

The Warden · #1 02-11-2003, 08:33 PM

Hello! Even after getting the upper control arm bushings replaced, I've had some complaints about the ride (bit of a vibration through the steering wheel and other "hard" parts, very loose wheel {probably the gearbox, but still}, etc). I went and made sure that the lug bolts were tight on the wheels just now, and noticed something. Both front wheels had some straight forward-to-back play. I thought this would have been fixed with the upper control arm bushings

but now I'm thinking more along the lines of the guide rod bushings...

Can anyone confirm this or point me elsewhere? It seemed like the guide rods were moving back and forward with the wheels, but I couldn't tell for sure (bad light and I didn't have a flashlight with me). If memory serves, I was told that there are bushings at the wheel assembly as well as at the mount to the subframe, but I don't remember being able to readily find them, and I couldn't readily tell what condition the subframe-to-guide-rod mounts were in (again, at the time I wasn't that concerned, as I had thought that all of the problems were related to the upper control arm bushings). I didn't see any rubber on the guide rod mounts, but there was enough metal that I figured that the metal was covering the rubber...or are they that bad?

Any thoughts, advice, or comments would be appreciated. Thanks in advance!

oilslick · #2 02-11-2003, 08:42 PM

Do you hear or feel any popping in the forward floor, kinda in the location where the guide rods mount to the frame? My guide rod bushings are bad and I feel and hear these noises coming from that location. I do feel the looseness in the steering but I am fairly sure that it's the box. I AM NO EXPERT!!!

Have a good'n

oilslick

DieselHead · #3 02-11-2003, 08:51 PM

If, when grabbing the wheel and shaking (not the steering wheel), you feel some looseness as if the wheel isn't tight, I'd take a look at the ball joints as well. But, like the last poster, I'm not expert.

Alex

The Warden · #4 02-11-2003, 10:03 PM

I forgot to mention that. Yes, I'm hearing noise, kinda like a slight groaning/popping...haven't pinpointed it, though. The previous owner thought the noise was coming from the anti-sway bar bushings, but I looked at the bushings and they seem okay...

oilslick · #5 02-12-2003, 10:59 AM

My MB mechanic said that it would cost $140 per side just for labor. Ouch!!! I might as well let him tackle it since I can't compress the spring to remove the end bolt.

Ouch!!! That hurts!

Oilslick

sixto · #6 02-12-2003, 12:15 PM

Warden,

I guess I'll be the one to say I told you so

The guide rod is a ball joint at the back end. It doesn't look like the spring has to come off on a W126. The W123 set-up is similar.

When they get really bad you'll feel a clunk as the car shifts forward relative to the guide rod when you slow down. My 81 SD was that way on the right side.

I don't know if worn guide rods will account for loose steering. AFAIK they're mostly to keep the wheels in place when braking. If the steering is loose at a stop of constant speed, I'd look for something other than the guide rods.

Have you checked that the bolts that hold the steering box to the frame are tight? Don't move them as they have some sort of thread lock on them. You might upset the thread lock is you give them anything of a turn. I think the manual says they shouldn't be reused but maybe they can be reused with Loktite.

Sixto
91 300SE
87 300SDL
83 300SD

samiam4 · #7 02-12-2003, 02:03 PM

Yep,

W123 bushings are doable without removing the springs. It takes a come-a-long and lots of force. Basically, you loosen the lower control arm bolt, pull the whole thing forward. Working it as you go, so as the lower control arm pivot will move.

Not a lot of fun.

Sounds like you really need to go through and diagnois the problems-check all the components for wear. It's the only cost-effective way of doing repair work. Shimmy/vibration to me would be more steering linkage(tie-rods, idler etc..) and the dampener.

Michael

gsxr · #8 02-12-2003, 02:42 PM

Sounds like the guide rod mount on the body is dead. If original with 235kmi, it's definitely shot. Mine were not sloppy yet, or making noise, but they were very loose... could move shaft around with my pinky. The new ones required large tools to move at all! I also discovered there are internal grease boots, and mine were gone! The dry wax-like crud inside had been grease in a former life. Ditto the ball joints. Everything on a W123 front end can be replaced with the spring in place EXCEPT the lower control arm bushings.

I just rebuilt my W123 front end and replaced EVERY moving and rubber item in the suspension and steering, including both control arms/bushings, steering links & idler arm, ball joints and wheel bearings. Wow what an amazing difference in ride quality. Still nowhere near as nice as a 124 but much tighter than before. I also have new OE shocks (from Rusty, $75/pop).

Photos of the job are here:
http://www.meimann.com/images/mercedes/W123_suspension/

The upper bushings almost fell apart in my hands, they crumbled into dusty pieces. The lowers were intact but oblong, notice the photo in-car where the arm center sits below the center line of the bolt. Ball joints were also gone, steering links were not bad but were cheap insurance. Old steering shock was 100% dead. Cost was ~$400 for ALL new parts. The photo shows how to use the free AutoZone rental tool to press the new joints in, if you pull the dust boot off and insert the joint into the tool recess with no spacer ring. Not pretty but it works!

Regards,

sixto · #9 02-12-2003, 03:07 PM

Dave,

Did you replace the subframe mounts in the area of the guide rod balljoint?

Sixto
91 300SE
87 300SDL
83 300SD

The Warden · #10 02-12-2003, 03:27 PM

Hoo boy...

There was definitely some red chalky stuff on the right side guide rod mount, but I don't remember seeing any on the left side. And, knowing the previous owners of this car, they're probably original.

Dave, BTW, when I replaced the upper control arm bushings, the old ones were just about completely destroyed (going by your pictures, mine were actually in far worse shape; as soon as I can get a digital camera I'll take some pictures of them; it's pretty impressive). There was almost no rubber left on them

How can I tell if the ball joints are okay or not? Last time I had the car in the air, I took the tie rods and tried to move them around; the only way that they would move was by rotating a bit to either side, which is about what I would expect with okay ball joints...but I will admit to not knowing what the ball joints are like on the wheel assembly (can't remember exactly where they attach; upper control arm??). The lower control arm bushings looked okay at a cursory check, but again, I'm not sure if they really are or not.

How were you able to tell that the steering shock was dead? And, at $400 for everything, this job will have to wait a bit; I just spent $400 on the car a few weeks ago and need to save up.

Sixto, yeah yeah I know...

Good to hear that pulling the spring won't be necessary for this...although if I'm also going to do the lower control arm bushings, I may as well, eh?

gsxr · #11 02-12-2003, 03:56 PM

Sixto, I didn't see any subframe bushings up front... did I miss that? I know there are some on the rear.

The Warden, the steering shock is easy to check. Unbolt one end and try to push it in & out. It should have a lot of resistance, like a normal shock absorber. Mine would push in & out very easily with little effort. Your lower c/a bushings may be OK if they look decent and are still centered. They're not hard to R&R but you need to pull the spring, which requires the special MB compressor, or some other more risky method of spring removal. If the ball joints are 235kmi old they're probably shot. Check the boots, if cracked or torn, you need to replace them as the lubrication has been exposed to water & dirt. They're kind of hard to test per the MB factory procedure, but I can say my old ones moved quite easily and the new ones were VERY tight and stiff.

The upper ball joint is part of the upper control arm, usually you just replace the whole thing rather than bushings only. The lower b/j is buried on the back side of the knuckle, as seen in my photos.

HTH,

sixto · #12 02-12-2003, 04:42 PM

Dave,

Maybe that's where the 123 and 126 are different. I thought all MBs of this vintage had a detachable front subframe suggesting that there would be bushings.

Sixto
91 300SE
87 300SDL
83 300SD