My Mk1 gives a single loud bang or crack shortly after setting off nearly every time. It only happens the once. It seems to be coming from behind the driver’s seat or from inside the boot. I thought it was a short circuit noise as if the battery positive was connected to the earth but since it only happens once soon after setting out and visual checks don’t show anything, I guess it must be something else. Otherwise the car is fine.
Can only suggest it may be brake pads. If you reverse to where you park and then set off forward you are reversing the rotational force on the pads. If there is play this can cause a clonk where the pad plate bangs onto the carrier.
Try reversing the car and then going forward to prove this theory.
Thanks rhino. I always have to reverse out of my drive before setting off. I have had brake pad sticking trouble before but this sounds much sharper and louder and happens some way into my journey, say 100 yards from setting off.
As above really
Also in this lovely dry climate we have the pads maybe slightly rusting to the disc over night
this can have an accelerated cause if there’s a slight brake fluid leak on the Caliper contaminating the pad linings as brake fluid attracts condensation / water
It’s worth checking out .
you can now ignore my post as it’s not a pad issue like that if it’s happening 100 yards or so up the road
next idea might be cv joints but again this is guess work from afar
Sticking pads normally show immediately when you start to move, it’s the noise that tells you what the problem is. As you say it happens within 100 yards after setting off, then I’d say it’s not the pads sticking. I avoid this as much as possible by using the gears to park on our inclined drive, rather than the handbrake. - I only use the handbrake and the gears if the car’s parked on the road. (Double safety). - No doubt someone will say I’m asking for trouble!
BUT - as you say the noise is louder than normal, it’s possible - despite what I’ve just said, - that the sticking is now worse, which may point to a sticking caliper(s), or handbrake cable. Are the discs relatively rust free?
- If the brakes are finely adjusted (close to the discs) then a rust buildup on the disc may also make the difference noticeable, and delayed.
Many thanks all. I will have to have a close look at the brakes when I get a chance.
I wonder if it might be something binding in the suspension and breaking loose again after a short distance. Have the suspension bushes been changed? Some cheaper poly types are rather notorious for seizing solid; I remember seeing pics of snapped upper rear arms caused by bushes that let the joint bind rigidly.
You can count/discount the rear brakes binding theory, by parking your car somewhere level overnight, and leaving it in gear with the handbrake OFF. If the bang doesn’t happen when you move away next morning - it’s the brakes.
But to be honest, that sort of stuck-brakes-releasing-bang normally happens as soon as you start to roll.
This afternoon, after the car had been standing all night, before doing anything else I freed the handbrake, jacked up the rear and both rear wheels turned freely. So I don’t think it can be the brakes. I’m wondering if it could be a momentary backfire.
I think the suspension idea might be a possibility since it seems to come from that area. But I don’t know how to check it. I’ll have to get my trusty garage man to have a look.
I have used WD40 and oil on all moving parts of rear suspension and have not heard the noise since, although I’m not using the car much at the moment.
If it starts doing it again try bouncing the rear corners before moving off to check the suspension.
Shoot me down in flames all you experts if you like but what about ARB bushes and drop links?
Many thanks Roadie, I’ll do that.