E270 defeated by seized Rear Swing Arm bolt ... any suggestions?

[james2747]

Hi
I am trying to replace a broken rear spring on my recently acquired 2003 E270 CDi.
I'm following a guide which tells me to unbolt the suspension arms at the hub end, remove shocker to swing arm bolt … then loosen the inboard swing arm to subframe bolt (the one, that goes through the large rubber bush … see photo) which enables you to lever the loosened swing arm down and remove the spring.
All went well till I attempted to loosen the swing arm to rear subframe bolt … the nut came off ok but the long torx bolt just wouldn't budge. I assume it is the original bolt that could have been in position for nearly 15 years now …. although looking at the service record that came with the car, the rear springs were replaced by Mercedes in 2009.
Gave it lots of releasing fluid plus some hefty bangs on both ends with a hammer to try to break any corrosion holding it …. plus lots of force applied trying to turn it, such that I could feel the torx grooves yielding as I applied maximum force using a torx socket and breaker bar.
I assume the bolt is corroded on to the swing arm as there is no movement at all.
If it was just seized inside the bush then I assume I would rotate a little as it would move as the rubber bush compressed round … but zilch … it just doesn't budge at all.
I didn't want to really force the swing arm down without loosening the bolt as it may damage the rubber bush so I had to put everything back together and try another day.
Will still need to remove spring in not too distant future as it won't pass MOT with a bottom coil snapped.
I assume I'll end up destroying the bolt before I can get it out so as a precaution I bought a new torx bolt today which cost £9 from Gloucester Mercedes!!!!! (yes a 12mm dia. torx bolt … what a rip-off).
Anyone had a similar issue with this bolt or any suggestions on how I could remove it.

 

[LostKiwi]

You could get an internal spring compressor and not bother removing the bolt.

 

[joderest]

Good suggestion, I suspect anything you try to remove bolt will end up damaging something, heat will damage rubber bush, i suppose i would give one last shot by attending a garage that has a air powered impact gun and ask them to try and move it, would only cost a small amount, if successful, could then just be nipped up to drive home so you can do the work.

 

[om613]

The torx splines look pretty shot now. Is there space enough to fit a large nut over the head and fill the hole with weld?
The heat will help and you can then put more torque on it.

 

[james2747]

Good suggestion, I suspect anything you try to remove bolt will end up damaging something, heat will damage rubber bush, i suppose i would give one last shot by attending a garage that has a air powered impact gun and ask them to try and move it, would only cost a small amount, if successful, could then just be nipped up to drive home so you can do the work.

Hi joderest
thanks for suggestion but I think the torx splines are just about on the limit after my attempts at turning the bolt … so an impact torx bit will probably round them off completely.

 

[M80]

If I'm seeing that correctly I guess the bolt really wants to be drifted out from t'other side.
Going with LK's suggestion sounds possibly easiest, but if you are preferring to replace the bolt and copper grease the new I would get the thing turning by use of a cold chisel and lump hammer as it's shot anyway.

"If at first you don't succeed get a bigger hammer" has worked for me a few times.

 

[james2747]

The torx splines look pretty shot now. Is there space enough to fit a large nut over the head and fill the hole with weld?
The heat will help and you can then put more torque on it.

Hi
Thanks for this suggestion which is probably going to be the only thing that will guarantee to shift it.
I'm just amazed at the force that's needed to break this bolt loose.
I did think of carefully grinding the complete head off the Torx bolt with my small angle grinder (without touching the swing arm … surgical precision needed) … but I just need to re-assure myself that the bolt isn't also seized in the bush spindle, as if it is I'd be really in the poo, as I'd no doubt damage the bush trying to hammer or drill out the remains of the bolt.
If … if …. if … only a dab of copper grease had been used when bolt was fitted!

 

[M80]

If you go for the grinding option I suggest cooling with water and a paint brush regularly.

 

[M80]

Is there room to get stillsons in there?

 

[umblecumbuz]

As the bolt will not move even a fraction, it would seem that it's well and truly welded to the swing arm. If so, this is good news (!) because it may not be bonded to the rubber bushing, which would mean that once the bolt head was freed, the stem should come out by drifting - from either side if you then grind the bolt head off. A steel wedge and percussion (lump hammer) between the bolt and the swinging arm may possibly loosen it.
If it's also bonded to the rubber housing, then grinding off the head gives you a bigger problem. I can't see an easy solution to that, other than leaving it as is and trying to replace the spring by compression - not an easy job at all.

I once wanted to change the prop on a boat I owned. The prop was held on by a self locking nut, doubled up with a split pin through the shaft. The nut came off easily but the prop wouldn't budge. It was rubber bushed, as some props are, and in the end we had to destroy the prop by cutting it in half in order to remove it. The rubber bush had hardened and was solidly welded to both prop and shaft. Hated rubber bushes ever since.

 

[om613]

Sometimes, the mechanical effort needed for such jobs, where rust is involved, way surpasses one's experienced expectations.
I replaced my 20 year old 202's rear discs recently, now this should have been a " 2 star" job, at most (and I didn't disconnect the battery).

No. Not so.
A lump hammer, FBH, wouldn't budge one of them.
Required was a sledge hammer / log splitter / "FMBH".

 

[EmilysDad]

Many, many years ago ..... I tried to change the void bushes on the wishbones at the front of my MKIII Cortina. I split a socket trying to remove the long bolt across the wishbone as the bolt was siezed solid. I ended up removing the complete suspension assembly, sawing through either side of the wishbone & drilling the remaining part of the bolt from the sub frame. The replacement bolt was only available from Ford at something like £30. In the early 80s, that put a huge dent in my wallet.

 

[LostKiwi]

Looking at that pic removing the bolt will upset an adjustment and require a suspension alignment afterwards (slotted mounting hole). I always try to avoid moving bolts that have adjustments associated with them. As you have already undone the other end there should be enough movement in the bush to allow the arm to move down (especially if you compress the spring using a jack under the arm, fit some compressors externally if you don't have internal ones and lower the arm again). The spring should then be able to be extracted with relative ease.

 

[bembo449]

I think the above is the way to go , remove the whole thing pal

 

[james2747]

Is there room to get stillsons in there?

Hi
Thanks for suggestion.
The Torx head is quite slim so not much for the stilson to grip on but I'll have one handy when I try again to replace the broken spring at weekend.
I think 'Lostkiwi' last suggestion may be a workable method …. as long as the bolt isn't seized in both the bush and on to the swing arm.

 

[james2747]

Looking at that pic removing the bolt will upset an adjustment and require a suspension alignment afterwards (slotted mounting hole). I always try to avoid moving bolts that have adjustments associated with them. As you have already undone the other end there should be enough movement in the bush to allow the arm to move down (especially if you compress the spring using a jack under the arm, fit some compressors externally if you don't have internal ones and lower the arm again). The spring should then be able to be extracted with relative ease.

Hi Lostkiwi
Thank you for your response.
You pointing out that I had undone one end should allow arm to swivel was good. I just assumed that as bolt was still 'tight' the arm couldn't be forced down without damaging the bush.
I'm having another go at the spring replacement at weekend so hopefully the bolt isn't seized on to the swing arm AND in the bore of the bush … in which case I could end up delaminating the bush if forcing the arm down..
I've bought a new bush and bolt just to be on safe side but I certainly don't fancy trying to replace the bush in to the rear subframe in situ. … even if I have got a few bush remover and installer tools!

 

[LostKiwi]

Hi Lostkiwi
Thank you for your response.
You pointing out that I had undone one end should allow arm to swivel was good. I just assumed that as bolt was still 'tight' the arm couldn't be forced down without damaging the bush.
I'm having another go at the spring replacement at weekend so hopefully the bolt isn't seized on to the swing arm AND in the bore of the bush … in which case I could end up delaminating the bush if forcing the arm down..
I've bought a new bush and bolt just to be on safe side but I certainly don't fancy trying to replace the bush in to the rear subframe in situ. … even if I have got a few bush remover and installer tools!

There must be a level of movement in the bush for it to work. To delaminate the bush it would have to be pretty shot already.