Changing rear coffin arms and tuning forks

Alex · 26 Aug 2019

Cut the bolts out. Wasting your time with any other ideas.

http://911uk.com/viewtopic.php?t=125503&postdays=0&postorder=asc&start=136

Kbald · 26 Aug 2019

Thanks. Just did the other side and the coffin arm bolt slid right out no problem so looks like only 1 to cut out which is a 50% bonus.

Now my new issue is the ball joints! How on earth would one go about getting these out? Can barely get a spanner in there never mind a ball joint splitter or hammer to hammer the hub.

Ive just done the tuning forks for now both sides and the squeak seems to have gone away. Not 100% sure the coffin arms will need replacing based on the front end as the rubber bushes were OK on these but the ball joint was loose so I suppose its best to do them.

Ghianightmare · 26 Aug 2019

If you have the funds, replace them. They will transform the handling.

Ghianightmare · 26 Aug 2019

A scene from my project

Kbald · 26 Aug 2019

I have the replacement coffin arms already for the rears so may as well do them. Just need to work out how to get the ball joints off due to lack of room in there! Trying to find a you tube video but they are all for the front ones which are all done.

Will get a resipricating saw for the side that the eccentric bolt won't come out of too.

deMort · 26 Aug 2019

Rear coffin arms ? sorry i haven't read all of this post but if rears then you remove the track rod arm .. you can then pull the hub Around enough to get a ball joint splitter on it .. not easy though .

If the 18mm nut spins on removal .. your kinda screwed .. doesn't often happen but at that point your into cutting off the nut .. access as you know is poor .

Always wire brush the thread and a small amount of lube to cover the threads ONLY before starting . .

Ghianightmare · 26 Aug 2019

Kbald said:
I have the replacement coffin arms already for the rears so may as well do them. Just need to work out how to get the ball joints off due to lack of room in there! Trying to find a you tube video but they are all for the front ones which are all done.

Will get a resipricating saw for the side that the eccentric bolt won't come out of too.

I could only get the reciprocating saw into one side of one of the bolts - I think it went in both sides of the coffin eccentric but only one side of the toe arm. In one place you will have to use the hacksaw blade in a handle and it takes a while circa 30 min to saw through as there is only about 20mm of blade travel. Use a new blade, mentally prepare for the boredom and you will get through it.

As demort says, if the Val joint spins you are goosed. I had been dousing all the bolts and nuts in penetrating fluid for weeks in advance and both rear ball joints came off fine. However, as I got carried away in the moment I release the LH rear with the nut still on a few threads because I was giving it a few whacks and so the nut was a bit tight and wouldn't spin off - it just turned the now free ball. So it took a bit of brute force and ignorance and a lot of cursing at my own stupidity to get it off - basically ripping the runner off and getting a vice grips half on the ball.

My front coffin was a longer story as the ball joint seat came out with it and then it took a further 3 days of overnight in freezer and then heat and then persuasion and then repeat - and eventually it came off the ball joint. And then more freezer and heat to get it nicely back into housing.

Best of luck - whatever happens someone in here will have run into a problem like you will run in to, so don't sweat.

Kbald · 26 Aug 2019

Thanks guys that's helpful. Will give it a go next weekend hopefully.

Re the hub insert I had this happen on the front offside ball joint. I was able to get it off with a 3 legged puller, using a spanner through two of the legs to stop the ball joint spinning, while clamped in a vice. Popped back in OK to be fair and put a bit of threadlock on it.

deMort · 27 Aug 2019

At work if this happens then we are screwed .. we have to replace the hub no ifs or buts as we and any other garage has to warranty a repair .

If it was my car then i would be trying what you and others have done .. refitting it .

MC has had success in pressing these back in .

All i would say .. and what i would do .. i would check for play after a week or so and then again after a month just to make sure it hasn't started to spin ..

If it does it will soon chew through the alley hub and you will have a serious weak spot .

Stay safe .

Kbald · 27 Aug 2019

Good advice demort as always.

Just to check how would you check if it was spinning? Hopefully there is an easy way.

deMort · 28 Aug 2019

It's a steel insert in an ally hub .. the splines as per the pictures lock it in place .

if it starts to rotate then it will eat away the ally .. you will in effect end up with play in the wheel .. wiggle top / bottom and side to side as a check ... you will see / feel play when you do this .

MOT check was a lever bar under the wheel and lift the wheel to check this joint whilst looking at it .. jacked up slightly and bar between the floor and the wheel to lift it , that would also work .. as said i would check after a week just to be safe .

I expect it will be fine .. but i always err on the side of caution .

Kbald · 1 Sep 2019

Thanks Demort haven't had chance to check for spinning as yet but did manage to fit the new rear coffin arms today. Nearside one was fine as the eccentric bolt came out fine. Needed to remove the cross member strut to get the arm out downwards to get it out of the way to get the pickle fork in which went fine.

Offside the bolt was still stuck and the metal sleeve was spinning in the bush. Bout a reciprocating saw but with it just jacked up on axle stands it was too big to get in there. Luckily I had one of those black and decker scorpion multi saws and this is basically a smaller bodied reciprocating saw so it worked a treat. £37 down for the other saw though but I'm sure it will get used for something.

Anyway jobs done are all coffin arms and tuning forks, engine mounts and front inner tie rods. Can get it aligned now or try do it myself again.

Kbald · 1 Sep 2019

Also when using a pry bar to move the coffin arm wiggling this there seemed to be some play in the track for bush. How much p!ay should this have? Is it common for the bushes to go on these too? I haven't seen much on there about them.

deMort · 1 Sep 2019

I'm not 100 % sure on what item you mean but ( photo ) rule of thumb is there shouldn't be any movement .. a flex on a bush is fine but not actual play in a suspension item .

A worn bush means you are pushing against a rubber bush .. it will give then return ..

movement is move it moves one way and it stays there .. move it the other and it stays there .

hard to explain im afraid .

The top arms .. well i've never replaced one yet .

Kbald · 1 Sep 2019

It's number 13 in the picture. There is some side to side movement like a flex in the bush.

Changing rear coffin arms and tuning forks

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