Weird noises '86 SDL - PeachParts Mercedes-Benz Forum

LUVMBDiesels · #1 08-02-2008, 08:45 PM

I am having a real headache with Rudolf the 1986 SDL I recently bought

It is making a clanking/tapping noise from the front end. When it coasts at about 25mph, it sounds like an old box truck! When it is under acceleration the noise stops.

I went under the car and the center link was very loose. I replaced it and the steering damper and the noise did not go away. I took it to a decent shop (not a MB indy though) and they checked it out I ended up replacing both upper control arms and the right tie rod. Well the noise is STILL THERE! We checked the rest of the front suspension was checked over and everything feels tight. The sterring is fantastic now, nice and tight almost BMW like. The shocks were replaced about two months ago with Bil HDs The tires are new and in balance. The front and rear flex fisks look brand new and are nice and tight.

Does anybody have a clue as to what this could be? I do not think that anything is about to fall off or that I will loose a wheel or steering, but i hate the nose and need it to go away.

The only rubber parts that look at all worn are the guide rod mounts. However, we could not get them to make the noise on the lift. My questions are do work guide rod mounts result in clanking/tapping noise? How hard are they to replace?

Thanks in advance!

Brian Carlton · #2 08-02-2008, 10:49 PM

The guide rod mounts typically won't make noise unless you're braking rather hard..............I can't imagine any noise at steady state as they are not loaded. Chasing them won't solve the problem.

What's the possibility of a bad wheel bearing? Can you determine if the noise is relative to the right or left side of the vehicle?

LUVMBDiesels · #3 08-03-2008, 08:39 AM

Thanks for the info Brian.

The noise sounds like it is coming from behind the wheels. That is why I was thinking about the guide rods. The noise also seems to be coming from both sides. I will check the wheel bearings tomorrow evening just to make sure they look good and are well packed with grease.

Brian Carlton · #4 08-03-2008, 09:48 AM

Quote:

Originally Posted by LUVMBDiesels

Thanks for the info Brian.

The noise sounds like it is coming from behind the wheels. That is why I was thinking about the guide rods. The noise also seems to be coming from both sides. I will check the wheel bearings tomorrow evening just to make sure they look good and are well packed with grease.

Firstly, if the noise is coming from both sides, you'd have to make the conclusion that both guide rods are equally bad. This would be unlikely unless the vehicle was neglected for quite a long time. One guide rod would go first.

This same logic applies to the wheel bearings. The chances of having identical problems on both wheel bearings is also very small. Additionally, you'll need to pay careful attention to the wheel bearing by rotating the rotor and "feeling" for it. It's not loaded under this condition and any issues in a bearing are severely masked when it's not under load.

Try to have another person drive it and observe the vehicle from the road as it passes by. See if the noise is more readily apparent by the observer. Do it from both sides of the vehicle.

LUVMBDiesels · #5 08-07-2008, 12:10 PM

No Joy in SDL town!

I replaced the right side wheel bearings and while this fixed the squealing noise, I still have that d@mn clicking noise at 25~40mph. I am at a loss here as I have replaced most of the front suspension. The car rides like new so I guess this is ultimately a good thing.

Does anybody have an idea as to what could cause this noise? I will have to record it somehow and post it I guess.

Brian Carlton · #6 08-07-2008, 12:15 PM

Quote:

Originally Posted by LUVMBDiesels

No Joy in SDL town!

I replaced the right side wheel bearings and while this fixed the squealing noise, I still have that d@mn clicking noise at 25~40mph. I am at a loss here as I have replaced most of the front suspension. The car rides like new so I guess this is ultimately a good thing.

Does anybody have an idea as to what could cause this noise? I will have to record it somehow and post it I guess.

Put it up on jackstands in the rear..........be absolutely sure of the safety.

Block the front wheels.

Start the engine and run the vehicle in gear at 25-40 mph...........with another person at the throttle.

Check around the outside of the vehicle and try to sort out the location of the noise.

If it doesn't make any noise, the problem is definitely in the front suspension.

LUVMBDiesels · #7 08-07-2008, 12:23 PM

I will try to do that this weekend. I just had the car at my indy and it was on the lift. He checked the entire front suspension and gave me the OK to drive the car (nothing will fall off and I won't lose steering) I will let you know what I see running the car...

bbail2x2 · #8 08-07-2008, 12:26 PM

have you checked any loose pieces of plastic or metal shrouds? maybe a hose or cable flopping in the air? or body trim?

Brian Carlton · #9 08-07-2008, 12:28 PM

Quote:

Originally Posted by LUVMBDiesels

I will try to do that this weekend. I just had the car at my indy and it was on the lift. He checked the entire front suspension and gave me the OK to drive the car (nothing will fall off and I won't lose steering) I will let you know what I see running the car...

Please be extremely careful with the jackstands when you do this. With the engine running and the drivetrain rotating, there are vibrations that are setup in the vehicle that will compromise a marginal support setup.

LUVMBDiesels · #10 08-07-2008, 12:56 PM

Quote:

Originally Posted by Brian Carlton

Please be extremely careful with the jackstands when you do this. With the engine running and the drivetrain rotating, there are vibrations that are setup in the vehicle that will compromise a marginal support setup.

I have done this in the past.

I put jackstands under the jack points at the rear, Wedge my ramps under the frame rails pointing 'out' like the feet you see on a backhoe for extra stability and I always leave the 3 ton jack under the crossmember I am a freak about not having cars fall on me!