W245 Control Arm Help!

[Wully]

Help!

We have a 2006 W245 in the family which suffered from a snapped CV joint last week and after replacing the driveshaft we've decided to replace some of the worn suspension items. This leads to the problem!

How on earth / what is used to remove the two control arm bolts securing it to the sub-frame? The nut of the rear bolt doesn't even have space to insert a ring spanner and even the narrowest of open ended spanners doesn't fit in. Why anyone designed a small rectangular hole in the sub frame for access is beyond me.

I've been through WIS and there is nothing about any special tools used to remove these. I can only assume the torx head of the bolt is loosened by an impact ratchet but the nuts are another story.

Anyone ever replaced one of these?

 

[Codger49]

Not familiar with W245s, I m afraid, but the implication I pick up from operation steps 6 and 7 in the attached WIS proc is that the bracket (5) clips around the nuts and undoing and tightening the bolts is actioned from the bolt head only.

Not impressed with the engineering here, maybe OK for first assembly, but tricky for maintenance/replacement, especially as 120Nm+90 degrees is quite tight.

Hopefully one of our experts will come along and elucidate.

 

[Wully]

Honestly don't know what MB have in mind when it comes to front suspension, as if the control arm issue with the W203, W204 & C207's aren't bad enough.

The "assembly aid" that's being referred to is simply a piece of metal that get exposed to the road constantly, you can imagine what condition it's in.

On the attachment if you look at the first photo on the second row, that section is off the W245, the size is a massive 70x40mm, what on earth can loosen / tighten to the torque specified in that space? I'm not up to speed on air tools but a 3/8" decent battery ratchet is no where near this figure.

 

[Codger49]

As I've said on another thread, but could've been t'other channel, I'm now into this for home use.
Ryobi R18IW3-0 18V ONE+ 3 Speed Impact Wrench Bare Unit 689744937348 | eBay

I'm getting more lazy and happy to. Setting 2 still needs the 'manual' torque wrench to finish tightening. On setting 3 I could probably teach those tyre fitters a lesson.

Oh, and there is no need to crack the bolts prior to jacking.

This was mentioned in the wheelnuts thread on Saturday - 400 Nm torque. Don't know about the access to the bolt head though, I would probably start with a 2 foot breaker bar with a socket.