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Changing rear coffin arms and tuning forks

Kbald

Well-known member
Joined
11 May 2018
Messages
221
Hi all. So far recently I've changed the front coffin arms and the tuning forks and the engine mounts. I then set about the rear coffin arms and tuning forks but have drawn a blank. I think I need to mark up the eccentric bolts on the coffin arms and wonder what the best way to do this is?

For the tuning forks there is a top bolt to enable you to undo the ball joint end but it's impossible to get any sort of spanner in there to hold it so does anyone know how I go about doing them too? Thanks in advance
 
You can get an open ended spanner in there. For the others just take a photo and unbolt it all. You will be getting the geometry done afterwards anyway. Good luck getting the eccentric bolts out.

MC
 
You will be cutting the eccentrics off, get a one of those hacksaw blade holders and a a pile of good blades.

Just mark the approx position and get it aligned afterwards at a garage.

The ball joint ends will be stuck in the hub carrier so don't worry about it just undo them and use a splitter.

Sometimes the steel insert from the hub carrier comes with it

Did you do the front inner and outer track rods too? Also front top mounts may need doing. Then you will have all new. Also front gearbox mount makes a difference, but wait till you drop the box for that.
 
Thanks. I did the inner track rods as the outers seemed fine. No top mounts yet either as prices for the carrera 4!

Mistercorn I tried with an open ended spanner but the gap wasn't big enough but must admit I didn't try too hard as I was thinking how will I get the bolt back in the bottom and line up with this nut in a tiny gap and even worse it it moves? Or is it locked in position so that's not a concern.

I'm still hoping I will be lucky with the eccentric bolts and don't need to cut them out as I have seen some posts on here that show the pain with the hack saw! Might get a resiprocating saw if I need to do that!
 
It's a 21mm for the top of the tuning fork. I've just done mine. You should be able to get the spanner down the gap so it is in line with the car and hold the top whilst undoing the bottom 18mm bolt head. The coffin arm I cut off flush and then cut in half with an angle grinder as the bolts were seized. Much quicker than a hack saw.
 
Thanks everitj does the top but stay in place then when removed?
 
Kbald said:
Thanks. I did the inner track rods as the outers seemed fine. No top mounts yet either as prices for the carrera 4!

The ones for a 997 c4 are much cheaper for some reason, a few people on here are using them have a search.

Everitj said:
The coffin arm I cut off flush and then cut in half with an angle grinder as the bolts were seized. Much quicker than a hack saw.

Thats the way to do it! (unless you are exchanging arms at Hartech for refurbed arms).

I don't remember having a problem getting a spanner on to undo the balljoint.
 
You may find they come undoone without needing to cut them..


:floor:


I used a reciprocating saw to get mine off, but I can see how a grinder would probably be a good deal quicker.

On the bright side, I recently replaced some parts of the front suspension on my car and because when I had first taken apart and reassembled that end about six years ago I had used copper grease, it all came undone without any fuss.
 
Re above can't seem to quote it but = I don't remember having a problem getting a spanner on to undo the balljoints.
It was the top nut on the tuning fork that was the issue rather than the coffin arms.

Thanks for all the suggestions. Where is the best place for the eccentric Bo?rs? OPC or are they generic sized ones I can pick up from eBay etc?
 
Various places do them but you'll probably find OPC are the cheapest.....and genuine.
 
Kbald said:
Thanks everitj does the top but stay in place then when removed?

No but there is a recess in the top of the casting that holds it in position when it comes to doing it back up
 
Everitj said:
Kbald said:
Thanks everitj does the top but stay in place then when removed?

No but there is a recess in the top of the casting that holds it in position when it comes to doing it back up

Perfect thanks
 
So just done the tuning fork. Think my spanner access issue was due to having the axle stands on the subframe. Have them on tne jacking point and now it's given me a touch more room and just enough to get the spanner in.

The coffin arms are still the old ones though. I got the nut off the eccentric bolt and could turn it but no way could I get it out. Is there anyway to do this at all!? Can't get a hammer in and a pry bar was doing nothing or is it a cut the bolts job?
 

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