Front corner of hood lifting / bouncing under way

[IslandMon]

I have a very annoying problem where the drivers side front corner of the hood lifts in the wind as speed increases, only mm's, but enough to see that it is raising and bouncing in the wind. It can be clearly seen since the reveal between fender and hood changes visually.

The hood is securely fastened at the center locking mechanism, and both corners are aligned well. The passenger side corner is more difficult to get to move when lifting up on it at a standstill. The drivers side corner raises slightly easier by a few mm's when pulling on it.

I thought it was a cheap aftermarket hood, and that a new hood would solve it. After switching to an OEM hood, the problem is still there, although a little better. Pic is right after car came from body shop, grill was awaiting new hood ornament.

I have messed with the hinges for hours to no avail. Everything lines up perfectly, and the hood bump stops are set so that the hood lines up with fender nicely at the front.


Any insight would be appreciated


Thank you

 

[gsxr]

Just to confirm - it's the leading edge of the hood, by the lights, which is lifting at speed? How fast are you going when it becomes noticeable?

 

[outrbnks]

Islandman, your a brave sole parking in a general public parking lot like that. So many people just don't give a dam, park too close to you, throw their doors open and it's a woops, sorry bout that, and that's it.

My wife still parks amongst the crowds like that most of the time, afraid walking another 100 feet from a remote spot in the parking lot is too much of an inconvenience, drives me crazy.

She'll even drive around the gym parking lot looking for the closest space to the door, before she goes inside to walk a few miles on the treadmill, I just don't get it...

 

[nocfn]

is all the rubber present for the leading edge of the hood?

 

[IslandMon]

Just to confirm - it's the leading edge of the hood, by the lights, which is lifting at speed? How fast are you going when it becomes noticeable?

Yes, the leading edge of the hood above the light. It probably starts around 50-60 mph and gets slightly worse at higher speed. I will update if I experience differently tomorrow.

Islandman, your a brave sole parking in a general public parking lot like that.

With 212k miles on the clock, I am a little less picky on parking spots. I am more happy about the engine getting me to that spot

is all the rubber present for the leading edge of the hood?

The continuous rubber strip on the underside of the leading edge of the hood is intact.

The gaskets on the underside of the headlights are intact, as are the ones under the filler strips under the headlights.
I am missing the gasket under my new p/s front fender, which was just replaced in an accident, but I do not have the hood lifting problem on that side. The gasket for that side is on order.

I appreciate the help.

 

[sheward]

Is the encapsulation panel present underneath?

drew

 

[IslandMon]

Is the encapsulation panel present underneath?

drew

It actually is not

Looks like for about $130 I could buy a replacement belly pan and try that

Any other ideas or tips would be appreciated. Thank you

 

[nocfn]

What about the heavy rubber for the center of the hood? New it was so heavy the hood wouldn't stay up for me.

 

[sheward]

I remember one or two other folks here with similar problems (such as turn signal lenses blowing out) that occurred when driving without the pan installed. You may be able to find one from a W 034 car or a member here.

drew

 

[speedy300dturbo]

This is a pretty common issue on W124s. As these cars age, the hood hinge bolts (usually the ones behind the fender liners) get loose, resulting in slight misalignment of the hood. The easy fix is to tweak the alignment of the striker, locking eye, and bump stops at the radiator support, but the adjustment range is quite limited and in some cases the hood needs to go "down" more to bring the locking eye closer to the striker.

Step 1: Raise the hood to the 90 degree position, mark the position of the bolts (circled in yellow) and loosen them.

Step 2: Pivot the hood forward a few millimeters, and tighten the bolts. Close the hood and adjust the bump stops until panel gaps are satisfactory and the corners can't be lifted up by hand.

Step 3: After making those adjustments, the hood may be slightly higher at the rear corners. With the hood in the 90 degree position, remove the fender liner and unhook the spring. Loosen the hinge mounting bolts (circled in blue) and close the hood. Have an assistant press down on the rear corners of the hood, and then tighten the bolts.

It's a lot of trial and error, but the end result will be worth it!

 

[Rouven036]

I never had to deal with the rear hinges.
The issue is more or less common to all mb cars with the central bonnet lock only. What you do: the lower bolt of the Y- shaped (marked green) stabilizer strut for the upper radiator support which also carries the bonnet lock has a elongated hole, you open it and push down the radiator support gently a few mm and retighten. Then get out and test it. Make sure your belly pan is on and that the outer front bonnet rubber buffers have some tension while still aligned with the fenders.

 

[Christian_K]

lots of good info here. Thanks Folks

 

[r44raven]

lots of good info here. Thanks Folks

+1

 

[nocfn]

And that picture of the Spruce car and red air box in post 10 is my car!

 

[gsxr]

This is a pretty common issue on W124s. As these cars age, the hood hinge bolts (usually the ones behind the fender liners) get loose, resulting in slight misalignment of the hood. The easy fix is to tweak the alignment of the striker, locking eye, and bump stops at the radiator support, but the adjustment range is quite limited and in some cases the hood needs to go "down" more to bring the locking eye closer to the striker.

Step 1: Raise the hood to the 90 degree position, mark the position of the bolts (circled in yellow) and loosen them.

Step 2: Pivot the hood forward a few millimeters, and tighten the bolts. Close the hood and adjust the bump stops until panel gaps are satisfactory and the corners can't be lifted up by hand.

Step 3: After making those adjustments, the hood may be slightly higher at the rear corners. With the hood in the 90 degree position, remove the fender liner and unhook the spring. Loosen the hinge mounting bolts (circled in blue) and close the hood. Have an assistant press down on the rear corners of the hood, and then tighten the bolts.

It's a lot of trial and error, but the end result will be worth it!

I've recently discovered on a couple of my cars that the hood hinge itself is the problem, and it causes the rear corner of the hood to sit too high - and adjustment won't fix it. One of the hinge pivots has excessive wear, the cure is to replace the entire hinge. If you raise the hood to a certain position (I can't remember offhand, d'oh) it is very easy to see the defective hinge pivot. I'll fiddle with one of them and report back how to check for the problem. This may not have any effect on the leading edge though.


UPDATE 1: To check for the worn hinge pivot, put the hood all the way up vertically. While in the vertical position, GENTLY rock the hood back & forth against the stops. If the hinge pivots are worn, you will easily see several millimeters of movement. On my cars, in both cases it was the passenger side hinge, at the forward pivot, near the front corner of the CAN box. With good hinges, there will be zero play at the pivots. Compare both sides, they should be the same. The play is only felt when the pivot is unloaded, it's not obvious with the hood closed or when open 45°.


UPDATE 2: Detailed photos & videos of hinge replacement, including before/after pics, are at the thread below:

FYI - 124 hood hinge worn, causing hood misalignment - SOLVED | Body Shop

The hood was not aligned with the fender, at the back near the windshield... took me a long time to eventually figure out the root cause was a worn hinge! Painted a replacement hinge, installed & aligned, now everything is flush again. Getting both sides aligned perfectly takes lots and lots of...

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