Strange Knocking - Fixed! Shoot me!

When I take my foot off the Accelerator to slow down (without braking) I get this strange knocking noise like something turning is catching the body.. sounds like it's knocking on the bulkhead but everything feels secure  :dontknow:

thought maybe it would be the exhaust but it's all fine…

anyone had this before?

I'm starting to think it could be internal to the Gearbox or more likely the Diff  :cry:

Been giving it some more thought and listerning very hard to the knocking noise

It's definately coming form the drivers side nearer the wheel so don't think it'll be gearbox or diff related

Could it be the top mount? when I replaced the shocks and springs one of them was a little more loose than the other (can't remember which side though)

any ideas?  :dontknow:

….er, could this be related ????

http://www.vwgolfmk1.o…ewtopic&t=3235&highlight=

To test what was causing it I jacked the wheel that was making the noise off the ground, gave it a tug to check for loose bearings (not loose) then turned it over and it squeaked at the point where the clip rubbed against the rubber bush.

However - if you're getting a knock, rather than a flub(!?), and it's only under deceleration, then it could be something to do with the differential/constant speed unit.

I've got an ancient haynes manual that says something about this - I'll read up on it and get back to you tomorrow. I have to say though - it does say that if something goes in the driveshaft type area, it's a replace the whole lot thing - not just a faulty component. Summit to do with tolerances.


Ali

hmm.. definately a knock and not a flub ( )

I've jacked the car up and tried wobbling the wheel, all seemed fine  :scratch:  I'll jack it up again tomorrow and see if I can get the knocking noise by turning it

Fingers crossed it's nothing major  :?

Is there any chance that your engine mountings could be loose or worn? - the engine would rock a lot when you come off the accelerator.

To confirm/dismiss this theory, hold the engine revs at about 1200 rpm and, with the handbrake on firmly, let the clutch up and down a bit, to make the engine rock as much as it can (shouldn't be much with good, tight mountings). Try it in first gear, and in reverse, to ensure you test all of the mountings.

If you can't recreate the knocking, then it's probably something else…

ah good idea!  :wink: I'll give that a go as well

It was missing the front engine mount (cup bit that bolts to the front panel)  ops: but as it never had a front panel when I got it I didn't know it should have one!

was hoping it was because of this but fitting it has made no difference (well… it's stopped the exhaust tapping the back panel at low revs), I think the damage has already been done  :cry: so it's just finding it so it can be fixed

If your front one has been missing for a time I would think the rear one has been 'kernacked' in the meantime…..cheap and easy to replace!

Prowler said

If your front one has been missing for a time I would think the rear one has been 'kernacked' in the meantime…..cheap and easy to replace!

Good point - whether this is the cause of the knocking noise or not, you should try the mounting-test above with the bonnet open to see how much the engine moves - if you're not sure how much is too much, ask a friendly mechanic to to judge it…

PS: If your car is a 1.1 or 1.3, and you feel the gear stick moving a lot under your hand, as you move forwards in traffic, then your rear engine mount is tired (a little bit is fine). On big-block cars, the linkage is different, and any excessive engine movement isn't transmitted to the gearstick.

Ah I see.. thanks guys

I get a little engine movement (about half an inch) when I rev the car..

it sounds more like something that rotates is clicking!  :? I've checked the drivers side drive shaft with the car in gear and can turn the wheel about an inch

Unfortuanatly I've got to drive to Milton Keynes tomorrow and friday   hopefully it'll be 'alright' until I find exactly where it's coming from and fix it! mind you, I've got AA cover! (who doesn't with a car that age!)

I'll let you know what it is when when I find it, keep the suggestions coming though  :wink:

PhillTMK1GTI said

it sounds more like something that rotates is clicking

Ahh, it's not the engine mounts in that case (and half an inch engine movement sounds fine).

ok - I've found the bit in the manual - It referred to noise caused by clutch problems - but it isn't described as a knocking.

If there's judder when taking up drive, apparently you could have loose engine mountings (checked this), contaminated friction linings, or worn splines on gearbox input shaft or driven plate… It then talks about engaging/disengaging clutch -  not when you just lift your foot off the throttle.

Hmmm - you're getting knocking but no judder.

If you're only getting knocking on one side, it might be worth checking that the wishbone isn't loose, and that the anti-roll bar underneath isn't flapping around. One loose rubber bush could result in it waggling around inside the metal bracket.

errrrr see if you can spot any bright metal caused by brake disk rubbing the plate behind the front wheel…

bonne chance

Ali

Manual also says that pre Nov 1979 models had a problem with front coil springs rattling when travelling over uneven ground (british roads?)…. not really a knocking though…

Given that you only get it when you lift your foot off the accelerator, it's probably weight transfer related - i.e. the front lifts under acceleration, then drops when you lift your foot off the throttle.

So you probably wont be able to get the front wheel to knock/rub when it's jacked up off the ground.


Ali

Think I've found out what's causing it!

Seems the rubber mount on the alternator bracket has seen better days and there's enough play for the bracket to be knocking on the engine!

Hopefully a new mount will fix it! but I could have swore blind it was something to do with the driveshaft/diff or top mount!

Phew - that sounds easily repairable.

I've looked more closely at my front wheel/CV joint boot - it can't be this. it does rub with the car jacked up off the floor, but not with the wishbone in it's normal position….

But I'm still getting a rub rub rub rub rub noise from the right hand side - I'm praying that it's driveshaft related.

If it's the differential or drive pinion - may be time for a new gearbox/engine…. siiiiiiiiiiiigh


Ali

AliCabrio said

Phew - that sounds easily repairable.

I've looked more closely at my front wheel/CV joint boot - it can't be this. it does rub with the car jacked up off the floor, but not with the wishbone in it's normal position….

But I'm still getting a rub rub rub rub rub noise from the right hand side - I'm praying that it's driveshaft related.

If it's the differential or drive pinion - may be time for a new gearbox/engine…. siiiiiiiiiiiigh

hope so! if it's not that then it could be the diff or maybe top mount  :dontknow:

is your problem deffinately a rubbing sound? wouldn't be something simple like the brake caliper sticking? although this would probably cause a squeek squeek noise… might be worth a look though

Might be worth a look

In the cabin you can just hear a ruub ruub ruub ruub noise that matches wheel speed (it can't be a small thing rubbing - cos that would go tap tap tap like a playing card tape to a bicyle spoke - the duration of the sound is longer).

It doesn't seem to vary with acceleration/deceleration - bit hard to say given the engine noise  

It doesn't go away under braking - which makes me thing it's not a brake sticking - and I couldn't see any shiny metal (other than brake surface) when I removed the front drivers side wheel for a look see.

I'll probably get a pair of front wheel bearings - replace those and see if that's sorted it.

I'll also check the gearbox oil

If that doesn't work - I'll know it's the diff or gearbox for less than the price of asking a garage to check  

Then the real fun will start……..

good point actually, if it doesn't go away under braking it's 'probably' not the calipers..

would be interested how much it costs to do the front bearings, heard they need to be pressed into the hub  :dontknow:

I'll keep you posted

I replaced the rear wheel bearings on my motorcycle last year - which required great forbearance on the part of the missus - she coped quite well with the hub in the oven and the bearing in the freezer   

If the golf requires similar treatment - no worries (might need bigger oven though….)

Ali

   

Did I mention  

well, thanks to Crazyquiff got a new alternator bracket.. but the knocking (on heaven's door) is still there  :cry: … got my girlfriend to drive slowly down the drive last night and from outside it sounds like it's coming from directly behind the drivers wheel!

I'm adjusting the camber anyway on Saturday so will see if I can find any loose brake parts!