DIY: Changing lower engine mounts

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Bennoz
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DIY: Changing lower engine mounts

Post by Bennoz »

Okay, as promised here's a guide on changing the lower engine mounts.

This is a relatively straight forward job if you dont mind a bit of time on your back (which is most of you beat-offs :lol:)

Tools required:
17 & 14mm ring spanners and sockets.

Bennoz difficulty spanner rating: 3/10
Bennoz "You f**cking c**t!" rating: 2

These 2 lower mounts wear quite easily & should be replaced every 100,000kms.

Signs that your mounts are wearing:
- Time between pushing the accelerator down vs the time it takes the car to take off is slow
- Dull thuds coming from the engine bay during acceleration & when easing off the accelerator
- large visible movements in the motor when revving.
- loud clang when revving the motor if the mounts are badly worn through.

Here is a diagram as to how the mounts become worn. The natural toque of the motor pulls the mounts in certain directions. Over time, the mounts will wear & eventually break through the rubber. The rear mount is renowned for being the weakest link - as you can see its physically smaller than the front mount. Also note, that when replacing a mount, you should always replace them both at the same time - because if you only replace one, then the strongest point will still be the weaker mount & the new mount will wear out faster as it is relying on the other, more worn mount. For high horespower applications, its recommended that the standard mounts are upgraded. You can have old mounts rebushed with polyurethane. It will make the throttle application much more responsive at a cost of more cabin vibration & noise.

Also note - the mounts are different on a manual vs a tip.

Part numbers:
Manual front mount: MR197540
Manual rear mount: MB691237 or MB949166
Tip front mount: MR131296
Tip rear mount: MR223674

Oh, and they are FTO specific mounts - therefore Mitsubishi Australia will charge like a wounded bull for them. I bought mine from Camskill in the UK.

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Both the mounts are bolted to the one crossmember - it has to come out to change them. The cross member is held in by 4 x 17mm bolts.

2 at the front of it:

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And 2 at the rear of it: (not so easy to get to with just a jack)

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Once you undone those, you then need to unbolt the actual mounts from the engine itself. For examples sake I have used the front one pictured here as I had more light there. Its just the one bolt that goes through each mount - they are often very tightly done up - hence the 2 x "You f**king c**t!" rating.

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As you undo the last mount bolt, the cross member will drop out quite easily. It will look like this: (note in this pic I have already replaced one mount)

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Now its just a matter of undoing the 2 x 14mm botls that hold each mount to the cross member & bolting on the new ones. While it doesnt matter which way the mounts face, it is important that the front & rear are kept seperate & bolted onto the same end of the cross member.

Here's a pic of an old mount versus a new mount. While it may just look dirty, if I poke a screw driver through the centre hole & move the rubber about, I can see cracks & effectively see daylight through the other side of the rubber. I've seen a lot worse thou...

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Reassembly is the exact reverse of removal.
- put the crossmember back in place & bolt the mounts to the motor (do them up tight!!)
- Bolt the crossmember back onto the chassis

You're done!
Last edited by Bennoz on Thu Jul 24, 2008 4:54 pm, edited 1 time in total.
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Shahrez
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Post by Shahrez »

Absolutely amazing Ben, very detailed yet simple to follow, although iam an engineering student, i rekon anyone with simple skills would be able to do that with no problem thanks to the way you have described what to do and how to do it with pics!! bravo!!
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Bennoz
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Post by Bennoz »

No problems at all :)

I too, am a mechanical engineer by trade (no longer in the industry thou.) Where are you studying?
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Shahrez
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Post by Shahrez »

sweet! iam studying Engineering and commerce at murdoch university in perth, WA. Doing Mechanical engineering and marketing and management for commerce. 3rd year now, first 2 years are boring, basic maths, physics, Matlab, CC, programming etc, but just starting to get into the fun bits! and commerce degree is mainly for the chicks :lol:
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jonowong
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Post by jonowong »

i thought you would have gone for the poly mounts ben...
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Post by Bennoz »

I will do. I just needed an old one, so I could get it rebushed.
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Storm
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Post by Storm »

I notice the mounts have holes much larger than the actual bolts which go through them. Is there a reason for this Ben?
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Post by AMACHA »

Im also doing engineering although electrical lol. ummm i noteiced you said the mounts are FTO specific.However when i bought the car there was abroken rear engine mount and the condition of the sale was that it gets changed.i was there when the mechanic called mitsubishi and the guy at chadstone mitsubishi (his name is lou knows mFTO's really well) said it shares the mount with a lancer wagon. apprently the wagan's and sedans have diffrent mounts???anyway i have a lancer wagon mount compared it to the old one on there its the same :|
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Post by col2560 »

poly mounts sound good, but who does em? someone in sydney?
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Bennoz
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Post by Bennoz »

Storm wrote:I notice the mounts have holes much larger than the actual bolts which go through them. Is there a reason for this Ben?
Yep, well actually the rear mounts hole is a direct fit for the bolt. So in essence, the rear mount acts as a pivot point - with the front mount being clamped into place by only the bracket against the crush tube in the mount. So if there is an major jolt to the engine, the front mount has room to give.
AMACHA wrote:Im also doing engineering although electrical lol. ummm i noteiced you said the mounts are FTO specific.However when i bought the car there was abroken rear engine mount and the condition of the sale was that it gets changed.i was there when the mechanic called mitsubishi and the guy at chadstone mitsubishi (his name is lou knows mFTO's really well) said it shares the mount with a lancer wagon. apprently the wagan's and sedans have diffrent mounts???anyway i have a lancer wagon mount compared it to the old one on there its the same
Im not surprised. They are very 'house & garden' looking mounts. There's probably half a dozen other Mitsi models that will fit.
col2560 wrote:poly mounts sound good, but who does em? someone in sydney?
UAS in Castle hill will do them on an exchange basis - but it'll cost you 200 odd bucks. RPW in Perth will also do them. For best value I'd recommend taking an old mount down to any poly supplier like Noletech.





Here's couple of happy snaps of db's rather f*cked rear one I swapped out the other day. An example of 'how not to let them get'

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There's also one caveat I'd like to add to they DIY - where I mention "While it doesnt matter which way the mounts face" - thats not true for tip models. The front mount on a tip must face the right way as its not a solid mount, but a directional mount. See pic below - this is taken from the passenger side of the cross member. The front mount pictured is the wrong way round. The second mount is postioned correctly - so that is aligned with the torque force the motor puts on it.

Image
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Storm
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Post by Storm »

Storm wrote:
I notice the mounts have holes much larger than the actual bolts which go through them. Is there a reason for this Ben?


Yep, well actually the rear mounts hole is a direct fit for the bolt. So in essence, the rear mount acts as a pivot point - with the front mount being clamped into place by only the bracket against the crush tube in the mount. So if there is an major jolt to the engine, the front mount has room to give.
Thanks Uncle Ben ;)
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Re: DIY: Changing lower engine mounts

Post by Ollie »

Hey Ben replacing the lower engine
mounts would u need sumthing to keep the engine up. because I'm worrid if I put my car up
on a hoist engine will fall or sumthing
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Bennoz
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Re: DIY: Changing lower engine mounts

Post by Bennoz »

Nah, the 2 top mounts hold it in place.
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Ollie
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Re: DIY: Changing lower engine mounts

Post by Ollie »

Thanx Ben.
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Storm
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Re: DIY: Changing lower engine mounts

Post by Storm »

I replaced mine with manual mounts, rather than tip ones but I haven't really noticed much of a difference.
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Bennoz
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Re: DIY: Changing lower engine mounts

Post by Bennoz »

Storm wrote:I replaced mine with manual mounts, rather than tip ones but I haven't really noticed much of a difference.
I ended up putting 1 poly one in place of the rear one. Does give somewhat of a shudder in the cabin now, but thats the price you pay for having as little torque loss as possible.

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Re: DIY: Changing lower engine mounts

Post by Ollie »

Hey Ben changing mi lower mount went very smooth only becuz I used an airgun n yur instructions.

Thanx.
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Re: DIY: Changing lower engine mounts

Post by Gholdwayne »

hang on a sec, i noticed that when im on first gear then hit the clutch for 2nd, sometimes, i notice that the car shudders too when the clutch disengages, but not from 2nd to 3rd etc. Does that have something to do with my mounts ? im almost at 90,000 on the odo by the way.
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Re: DIY: Changing lower engine mounts

Post by zuihoujueding »

mine is shot. need to replacement asap.
im interested in getting the upgrades from UAS but does the urethane really worth $190 a pop?
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Re: DIY: Changing lower engine mounts

Post by zuihoujueding »

Hey Bennoz, can comment on my question above?
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