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How to replace a coffin arm *another for the FAQ*

Lloyd Six

Well-known member
Joined
4 Nov 2008
Messages
879
The 996 & 986 suffer greatly with sqeaks and creaks, tram-lining and wandering.

The common cause is the front lower arm, known to the trade as the 'Coffin arm' due to it's shape.

The time required to remove and refit is under 1.5hours

Tools required

Min 1T trolley jack (hopefully better than my Halfords effort)
Axle stand (ensure you do use one as this job will incur a couple of hard clouts, too risky to rely on just a jack)
2lb Lump hammer
Flat ended screwdriver
230120101505.jpg


Also require
New Coffin arm (note the shape)
WD40
Grease
16, 17, 18, 19 & 21mm spanners
10, 18, 19mm sockets (in 1/2" drive with ratchet)
Usual wheel removal tools
230120101503.jpg


Jack up car and support with axle stand, remove the wheel
230120101496.jpg


Spray all the obvious areas with WD40 to aid the undoing of bolts

Remove the plastic guard using the flat ended screw driver from the arm to gain more access
230120101497.jpg

A useful photo so you can see how the clip works
230120101504.jpg


Use the 18mm socket and 21mm spanner to remove the nut & bolt from the bush in the middle of the coffin arm, once removed pull the support arm & swing towards front of wheel arch
230120101499.jpg

230120101502.jpg


Use the 17 or 19mm spanner (depends on nut size) and udno the nut on the out ball-joint which joins the coffin arm to the hub. Undo until the nut is flush with the top of the thread.

To release the ball joint it will require a few hard clouts against the arm as per photo below... don't be shy here, they take a fair wack but don't hit your wing or the brake disc.
If you think it has freed then LIGHTLY tap the nut that you left flust with the top of the thread, it should now be free. If you can not release the ball joint, put it back together and pass it to a pro, I feel siezed ball joints are beyond basic DiY
230120101501.jpg


Use the 10mm socket to remove the Black plastic nut holding up the splash guard
230120101498.jpg


Then use a big spanner to prop the guard out of the way
230120101500.jpg


Now remove the bolt on the inner coffin arm bush (16 & 18mm spanners)

That's it.. it is now removed. The refit is a simple reverse of the above, inner bush then ball joint then middle bush. Grease up all the nuts & bolts, I use anti-sieze compound.
 
Lloyd,

Just thought I'd add my appreciation for your informative and well written posts. They are always useful and interesting.

Cheers
 
Thank you once again. You must have bought a twin of my car as you have all the same problems as I do. This is the job I have to do next along with the forked control arms. I have both creaks and clonks over bumps. Since I have replaced the ARB links and bushes it must be one or the other. Thing is my coffin arms were only replaced 30 months and 25k miles ago but I don't think they were original parts and are starting to wear again.
 
Just did my nearside front ths afternoon. Took about 2 hours to get it off and 20 mins to get the new one on. Needed to get the ball joint splitters on it as it was a bit tight. I used the scissor type splitters as I wasn't sure I would have enough space to get a hammer on the other type.

I'll do the offside on Monday but my annoying clunk seems to have gone now so thats a good thing and worth the effort.

Cheers

Update: Done the other side this morning, took less than an hour (still needed to splitters though to get the ball joint apart) :thumb:
 
I think this maybe something I will need to do soon.

Do you need to get the tracking done after the arms have been changed? I have been informed that you do by some and some have said that you don't.
 
P996 said:
I think this maybe something I will need to do soon.

Do you need to get the tracking done after the arms have been changed? I have been informed that you do by some and some have said that you don't.

No, this job does not have any impact on caster, camber or tracking.
 
great post,certainly can save some money and not as hard to replace
as you may think :thumbs:
 
Did this today, wish I'd seen this first as I'd read a couple of guides on other forums but this is better.

A couple of things I'd point out - apparently the 18mm is a real odd ball size, so check you have one. Not only did I not have anything 18mm but for most bolts there I couldn't fit a socket. Ended up with emergency run to halfords and got an adjustable ratchet one (£16! :eek: ).

Also, apparently it's quite common for friction to weld the balljoint bolt in - in my case a hammer wouldn't do it, luckily the father in law had a ball joint separator. Nearly shat myself when it popped out - more like exploded out! :lol:
Oh, and also needed a torx (I used a small one held with shifters -can't remember size) to tighten nut onto ball joint.
 

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