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Help! Big Clunk When Accelerating Or Lifting Off Accelerator


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#1 kkeith

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Posted 14 September 2019 - 08:48 PM

Hi,

Recently purchased a 1996 Mini Equinox. Lovely car but the above is happening. Changed the Lower Stabiliser with Poly Bushes and the Upper with the performance one piece bushes from Minispares but didn’t make any difference.

On inspection the front subframe front mounts appear to be new (rubber) and one of the rear mounts looks relatively new (rubber). The driver side rear mount does look tired.

Checking/replacing the engine mounts sounds like a fairly big job.

Am I right to say it is now either the front subframe rear mounts or the engine mounts? I’m pulling what little hair I have left out trying to work this out.

Thanks
Kevin

#2 unburntfuelinthemorning

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Posted 14 September 2019 - 09:01 PM

Engine mounts aren't a big job but are fiddly.

 

Could also be driveline shunt from worn CV joints or other components.



#3 Cooperman

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Posted 14 September 2019 - 09:03 PM

It could conceivably be a badly worn diff pin if it is not sub-frame mounts or engine mounts.

 

You would be wise to replace the rubber sub-frame mounts with a solid mount kit.

 

Another possibility is a steering rack on the way out.



#4 kkeith

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Posted 14 September 2019 - 11:01 PM

Thanks for replies guys. Appreciated. Will replace the subframe rear mounts next then with the solid ones and hope does the trick. If not engine mounts, diff pin, steering racks, CV joints. ?

#5 unburntfuelinthemorning

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Posted 15 September 2019 - 06:34 AM

You should be able to tell if your rear mounts are alright or not by levering between the body and the subframe.  If they're broken then movement will be obvious.  A standard replacement will be sufficient unless you want to start upgrading the handling in which case you need to replace all six of the front mounts with solid, not just the rear ones.

 

Try holding a driveshaft with one hand and turning the wheel with the other to see if there's any appreciable play in the outer CV.  Then hold the driveshaft and turn the pot joint to check for inner CV play.  There will be a very small amount of movement but it shouldn't be much.



#6 kkeith

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Posted 15 September 2019 - 07:18 AM

Thanks - I’m nervous about tackling the subframe mounts. Can I ask a few questions as the Haynes is brilliant but also somewhat confusing at times:
This is all related to the front subframe...
For the front mounts it seems fairly straight forward to replace them, jack up, loser bolts to rear mounts, remove from mount bolts, lever a bit and hey presto.

For the rear mounts, do I jack up the back of the car or the front (this is where I found Haynes confusing)? Once jacked properly, it seems fairly straightforward to undo and lever out the existing rubber ones, with the help of an assistant inside the car on the bolts.

Now, for the top mounts, this is where I can’t find any info on how to do it (perhaps I’m not calling them the right thing and that’s why I can’t find them in the book). If I manage to buy a socket big enough for the nut which appears to be inside the engine housing near the bulkhead, how do I get to the underneath of that?
Lastly, I kind of get the physics but can I not get away with replacing the rear and front mounts with solid/poly and leave the top one?

Finally, the engine mounts - are they fiddly because of the amount of stuff you need to remove such as radiator or is there far more too it?

Thanks so much - need this damn clunking noise to go away.

#7 CityEPete

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Posted 15 September 2019 - 08:11 AM

Thanks for replies guys. Appreciated. Will replace the subframe rear mounts next then with the solid ones and hope does the trick. If not engine mounts, diff pin, steering racks, CV joints. ?


You must not do that!


Either all solid or all rubber, half and half will split the body shell.

#8 timmy850

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Posted 15 September 2019 - 09:17 AM

Another thought is the lower arm bushes or the tie bar bushes. I had a bit of an intermittent knock when accelerating/braking and found while checking through the car that the lower arm bushes were absolutely shot. I don't recall hearing the noise since changing the bushes

48534335701_36a0b2a7b2_b.jpg



#9 kkeith

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Posted 15 September 2019 - 10:36 AM

Thanks. I just had the car in first gear with handbrake off and with an assurance gently rocking car back and forth I didn’t see much movement other than the exhaust where the bend is up to the engine - it appears to move up/forwards slightly.

#10 unburntfuelinthemorning

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Posted 15 September 2019 - 10:52 AM

For the front mounts it seems fairly straight forward to replace them, jack up, loser bolts to rear mounts, remove from mount bolts, lever a bit and hey presto.

For the rear mounts, do I jack up the back of the car or the front (this is where I found Haynes confusing)? Once jacked properly, it seems fairly straightforward to undo and lever out the existing rubber ones, with the help of an assistant inside the car on the bolts.

Now, for the top mounts, this is where I can’t find any info on how to do it (perhaps I’m not calling them the right thing and that’s why I can’t find them in the book). If I manage to buy a socket big enough for the nut which appears to be inside the engine housing near the bulkhead, how do I get to the underneath of that?
Lastly, I kind of get the physics but can I not get away with replacing the rear and front mounts with solid/poly and leave the top one?

Finally, the engine mounts - are they fiddly because of the amount of stuff you need to remove such as radiator or is there far more too it?
 

To replace the mounts (front or rear) you need to support the car carefully under the floorpan in a way which won't damage the floor.  This takes the weight off of the subframe mounts.  You can use a jack under the subframe to provide a little support as you loosen the mounts then lower the jack slightly to get the mount out.  To do the front uppers you'll need to remove the large tower bolt on the bulkhead.  I'd suggest doing one side at a time on the front.  Spray plenty of penetrating fluid around the bolts before attempting to remove them.  Be especially careful undoing the bolts for the front mounts on the rear subframe where they go into the rear end of the sill.  Ease them out carefully.

 

Nearside engine mount isn't too bad although removing the radiator makes it easier.  I find the annoying one is getting the rear of the two mounting to subframe bolts on the offside mount as the flywheel housing cover restricts access.  Needs patience and imagination to fit that bolt.



#11 Chris1275gt

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Posted 15 September 2019 - 01:29 PM

Check the battery is secure in it's box and the exhaust is solid before you start pulling it apart.

#12 kkeith

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Posted 15 September 2019 - 04:06 PM

Can anyone tell me where I can find the page in the Haynes manual for replacing the bushes on the tower front subframe (the ones where you need to undo the large bolt which is in the e gone compartment) - I assume you can do this without having to remove the entire subframe? thanks

#13 unburntfuelinthemorning

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Posted 15 September 2019 - 04:30 PM

The Haynes manual usefully omits this information. 

 

You don't have to remove the subframe, just lower it enough to replace the rubbers.  As I said tackle one side of the car at a time.  You need a 15/16" socket for the tower bolts.  Watch the brake lines, fuel line and clutch hose as you lower the subframe to ensure they aren't damaged.



#14 kkeith

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Posted 15 September 2019 - 04:40 PM

Sorry if now sounding completely naive but can I ask, is this a job you can do to a working car as in one with full engine in etc? When you say lower the subframe that makes me think it is major surgery or it is a simple as undoing the bolt? Really appreciate your help.

I guess I’m after a basic bullet point guide as to how to change all the front subframe mounts.

#15 unburntfuelinthemorning

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Posted 15 September 2019 - 06:34 PM

Yes you can tackle the job with the engine still in place.

 

If you held the car up in the air using a crane with a large magnet on the roof of your car you could then undo the subframe mounting bolts and the subframes along with the engine would fall out. 

 

The trick is to support the subframes on jacks so the subframes can be lowered just a little rather than falling out.  At this point the mounting rubbers can be replaced.






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