The 'E' Type Forum

Anyone any ideas about a bonnet shudder when driving. Thinking it was shock absorber related I put new shocks on the front but shudder (over bumps) is still there. I have checked all bonnet fixings/ locks and there is no movement in the bonnet mounting at all. The subframe is fully attached to the engine frame and body.

Hi.....can you detail a bit more whats happening......is it the bonnet or whole front end.....whats the condition of the front suspension mounts, and engin mounts.....have you had it mot,d lately

mgcjag wrote:Hi.....can you detail a bit more whats happening......is it the bonnet or whole front end.....whats the condition of the front suspension mounts, and engin mounts.....have you had it mot,d lately

MoT'd March no issues. From where I sit it is the front of the bonnet. All mounts are good. Subframes securely mounted

But what is happening......what do you mean the bonnet shudders......need a better or different explenation of the problem......have you checked suspension bushes, bonnet mounts or cracked frames.....

I would start by checking that the bonnet hinges are securely attached to the bonnet and that all the pivot components are present, correct and in good condition. The bonnet is a very heavy unit and it's sheer mass can fool you into thinking it's secure on the hinges. Get underneath at check it with the bonnet closed as well.

Regards

FWIW one of my bushes - the bit that is supposed to be brazed to the frame for the hinge to screw into - had come unbrazed. I wasn't driving the car but it fell out when I went to replace the hinge bushes.

Since last communication I have been back to my MoT station. We have checked every bush and joint the length of the car. Also wheel bearings, bonnet fixings, engine mounts etc. No issues found.I am looking at tyre pressures now. Perhaps my spanky new tyre pressure gauge is not accurate ie too high pressure = less flexibility = hard ride = vibration in a large panel!!

What is happening at the back edge of the bonnet when it 'judders'? Is that moving relative to the scuttle also? I presume you've checked that the movement isn't within the bonnet itself - i.e. loose bolts that hold the sides on (the 'wings')?

Back edge of bonnet is firmly locked down. Every thing solid as per last post.

And there's no movement between the hinge attachment to the bonnet and the rest of the bonnet? Can you reproduce the movement by hand when stationary?

Any movement is not seen at all in the bonnet in any position from closed to fully open. Only when driving and over ripples or bumps. As before, everything was checked yesterday.

Hi...whats your name....try to put it in as a signature along with your car year model......may be worth taking the car to one of the mot garages that have a shaker...basicaly you drive on a ramp and the wheels sit on plates..they turn on the machine and and it starts to move the suspension in all directions to simulate a bouncy road.....you can then look from underneath for unwanted movement........when i got my car it was really bouncy and drove like an old bed.had it checked over and could find no movement.....put it on the bouncer machine and you could see the movement in the bushes..... Steve

Here's another off-the-wall idea - can you get a dash-cam under the bonnet somewhere pointed at the hinge area or wherever, then find a bumpy road & see if you can see what's moving. Don't know how you'd light it up though. If you don't have a dash-cam, a small child might work.

Is the car running really rough? I ask because if its running smoothly, I can't see why there would be a "shudder" even if fixings are worn/loose. If there's a bad vibration, then something as long as an E bonnet could perhaps shake regardless of how good fixings are?

Hugo wrote:Here's another off-the-wall idea - can you get a dash-cam under the bonnet somewhere pointed at the hinge area or wherever, then find a bumpy road & see if you can see what's moving. Don't know how you'd light it up though. If you don't have a dash-cam, a small child might work.

I have a USB camera with built in LEDs and a 15m cable. Just the ticket for this kind of stuff. Plug it into a laptop, some even work with a phone.

The 15m cable is a bit OTT. I would get one with a 7m cable if I were to start again.

Between magnets, a bit of soft wire, tywraps and duct tape you can rig it to point anywhere you want.

Great for looking inside a fuel tank to see if the float is sunk, or hanging up. I've used to look at the underside of carbs and other places where a mirror would take an additional hand to hold.

When you're trying to see relative motion of a bushing like the bonnet hinge it helps to use a paint marker to mark the joint: an "H" straddling the joint will show two degrees of freedom. Even if the picture is shaking around a bit, and the LEDs aren't quite bright enough, the white paint gives enough contrast to see what is going on.

Not so "off-the-wall" as I thought then! I have the audio version of this - a stethoscope with a remote microphone attachment that you can stick in odd places while you listen through the earpieces.
But I like this idea of a USB camera, even if it's a bit hi-tech for me; I don't possess a laptop, and I still have a phone with proper push-buttons on it.

Hugo wrote:Not so "off-the-wall" as I thought then! I have the audio version of this - a stethoscope with a remote microphone attachment that you can stick in odd places while you listen through the earpieces.
But I like this idea of a USB camera, even if it's a bit hi-tech for me; I don't possess a laptop, and I still have a phone with proper push-buttons on it.

You can get a used laptop with a decent spec for next to nothing - well worth it just to have a machine in the shop for displaying the shop manual, photos from disassembly etc.

Last Fall Aldi had 10" windows 10 tablets for just over 30 GBP I almost got one as the battery on my "shop" laptop is nearly dead, so I have to be careful when using the USB camera when out on the road testing.

You can also get very narrow cameras (5.5" OD iirc). You know when you notice that a 1/4" short extension has gone missing, and you've got the top of the chain chest open? For a modest outlay you can get a good nights sleep.

If I got myself a laptop or one of those fancy smart-phone things, I'd be spending all day on eBay & Facebook & E Type Forums & stuff! The only reason I have a computer is to listen to internet radio