W124 arb bracket keeps on snapping

[SilverSaloon]

Hi

On my silver W124 estate the front ARB bracket on the drivers side keeps snapping.

I've replaced it 3 times now. The 1st time I put it down to age and replaced the rubber bushes at the same time with MB parts.

2nd time i put it down to duff replacment (non-MB but MELEE branded) and replaced just the bracket

3rd time I read up on here and ensured i didnt tighten the rubber mounts too tight and made sure all 4 wheels were on the ground before i did up the nuts.

now its snapped again.

Should I be looking at a new ARB bar or genuine MB bracket, or something else.

cheers!

Derek

 

[kth286]

are you talking about the inner bracket that hangs down and holds the bar?

OR the clamps that hold the ends of the bar near the wheels?

 

[grober]

My only guess would be the front spring/shocker /suspension arm bush on the side in question is broken/weak meaning the roll bar is taking more suspension loading than its designed for?

 

[SilverSaloon]

its the "inner" mount, ie nearer the centre of the car.

about 4 months between snaps.

I'll check the suspension mounts on that wheel, thanks. Worth noting the car passed MOT between having a snapped arb mount - i replaced it for the MOT but snapped a few months later, so the suspension parts would of been tested then i guess.

 

[grober]

Guess there's nothing stopping you re-enforcing both mounts with some extra metal welded in place??

 

[balge]

Had one go on my 300TD. I don't think they like sleeping policemen very much...or high kerbs

There is a small reinforcing brace which goes between the bracket and the top mounting bolt which may have been lost?

I used a different nut and bolt at the clamp, to reduce the clearance, and large washers both sides to 'spread the load' - it's been ok for two years now so touch wood...

 

[SilverSaloon]

Had one go on my 300TD. I don't think they like sleeping policemen very much...or high kerbs

thats exactly where its broken on mine on all occassions.

Thing is I have another W124 estate which drives the same roads and not had a problem at all...

I thought about buying a new bracket and welding extra metal bracing to it. I'll also try the idea of adding big washers to it and different bolt.

the "spacer" thing is still there too. I did think about spacing it even more so it effectively sits lower maybe... but i would prefer a "proper fix".

 

[balge]

Looked like it fractured from vibration to me, so I tried to reduce the movement in as many places as I could, can't remember if I drilled the bracket or found an Imperial thread that was tighter clearance in the end...I remember I tightened the frame bolt last and made sure it looked as straight as possible in case it was being pulled off-centre...got quite picky, but it's worked so far.

Thought about reinforcing my new one, but worried it might cause a failure somewhere else, easier to replace the bracket than repair the frame mounting, for example

Seems some cars do it fairly frequently, but I suspect many are due to vibration fractures...maybe the bracket has a resonant frequency too near the car or something mad...maybe try welding a weight on the bracket