Anti-roll bar link rod

[Chai]

Is there a trick to unscrew the nut at the top of the link rod for the anti-roll bar?
The nuts at both ends just spin around and does not move up the threaded bolt. I've even tried with a lever pushing down the top side of the bolt while unscrewing the bolt from below - no success.

It has been after many years since the front suspension was removed and I only just noticed that the anti-roll bar link rod is missing a washer and this means:

• The rubber bump stop is able to slide over the sleeve/tube that keeps the top and bottom separated (lower arrow).

• The anti-roll bar doesn't function as designed as the bolt and its sleeve are able to slide through the hole in the lower steering arm (bolt move down and appears below the steering arm).

Anti-roll bar control arm.jpg

Anti-roll bar control arm link - upper bolt.jpg

[CraigB]

So if you grip the rod (say with narrow multi grips), the nut still turns on rod but not moving on thread ? If so, only thing i can think of is a nut splitter - most tool places should have or ebay. If the whole rod turning and need to grip, another way is to put two nuts on exposed end of thread and two spanners to tighten them against each other. Hope that makes sense and helps

[Christo C]

Bit of penetrating oil on the nut & thread might help; leave it to work for a day or so; then hold rod with vice-grips, or a couple of opposing nuts at top as Craig suggests…

[Chai]

Re-read my explanation and I had better elaborate on "the nut at both ends". That was meant to say that the same 'problem' occurs on both the left-hand and right-hand side of the car. It made me think that MB likely designed the nut to be 'free-wheel' once screwed on - meaning it doesn't need locking nuts and will never be able to come loose.

The bottom end of the link rod has a 13mm bolt head. That's where I had the ratchet wrench with a 13mm socket trying vainly to work that bolt loose. A ring spanner on the top bolt stayed put when the spanner hit the nearby brake assembly.

A nut splitter may be the answer here. I had thought about cutting the bolt with an angle grinder and buying a 300mm bolt, sized for a M8 nut, as replacement, but unsure if that has the risks the (self-locking with thread locker) M8 nuts working loose over time.

[CraigB]

I reckon someone might have kept tightening and once it ran out of thread, the path of least resistance was to strip the threads in nut and bottom of bolt thread. If I am remembering right and it is a long bolt and has spacer tube missing, then cutting of that nut might leave enough thread for it to work still. A nut splitter might spread the nut enough to spin it off without further damage but another split at 180 degrees would probably split in two. Really carefull cut with grinder on opposite sides might work.

[Chai]

Thanks Craig. Is very likely what happened at the workshop - kept tightening the nut and was able to reach the end of the thread because of the missing washer.
I'll try to angle grind the stuck nut out (don't have a nut splitter in my tool kit). I'll do like your said, carefully - the website for the local hardware store only has bolts with length up to 150mm (need 300mm).
Then address the reason for this work - replace the missing (mudguard) washers at the sleeve end to stop the rubber bumper sliding over the sleeve.
Will add a new short sleeve as spacer to clear the stripped threads on the bolt and washer before screwing in a self-locking M8 nut.

[Bartman4800]

If bolts available are too short, just get yourself a meter of threaded rod in M10 and cut to the correct length. Couple of nuts as well. Cheap as chips.

Regards, Bart

[John Green]

Thanks Craig. Is very likely what happened at the workshop - kept tightening the nut and was able to reach the end of the thread because of the missing washer.
I'll try to angle grind the stuck nut out (don't have a nut splitter in my tool kit). I'll do like your said, carefully - the website for the local hardware store only has bolts with length up to 150mm (need 300mm).
Then address the reason for this work - replace the missing (mudguard) washers at the sleeve end to stop the rubber bumper sliding over the sleeve.
Will add a new short sleeve as spacer to clear the stripped threads on the bolt and washer before screwing in a self-locking M8 nut.

When replacing these we use a kit that contained everything new. As in new long bolt all the washers rubber bushes and nut. I think I have some left at work. Not there till next Tuesday so give me a call then if interested.

[der_panzer]

Long story short - most kits give you the thread and nuts so cut it off. Normally on the non threaded part there should be a flat spot where you can get a shifter onto it. Failing that a set of multigrips done up will give it enough.

[Chai]

Have bought the kit from John Green but haven't had time to replace it yet.
Will post photos of the repair.

20220506-232723 450SLC anti-roll bar struts.png

[Chai]

Identified that the problems with the anti-roll bar struts (missing washer and nut stripped on bolt shaft) were when the air-conditioner update occurred, as that was when the anti-roll bar was removed to provide access for the A/C compressor.

Used an angle grinder to cut the old bolts. Worked alone so another bottle jack was useful to lift the anti-roll bar during installation.

The new bumpers are taller so the self-locking nut now sits on the top end of the bolt.

20230117-114409 Car anti-roll bar struts - new and old bumpers.JPG

20230117-114419 Car anti-roll bar struts - new and old bumpers.JPG

20230117-120201 Car anti-roll bar struts - cutting off old with damaged nut using angle grinder.JPG

20230117-113247 Car anti-roll bar struts - cutting off old with damaged nut using angle grinder.JPG

20230117-114804 Car anti-roll bar struts - installing new struts.JPG

20230117-124636 Car anti-roll bar struts - installing new struts.JPG

[der_panzer]

Much better,

If you got the while kit with bolts and nuts I usually just run the angle grinder through it with a death wheel attached. It look like Craig B suggested, someone redfed it up (most likely with an impact driver) and kept on tightening forcing the washer to pass down the spacer.

Sometimes cordless power tools cause more trouble than their worth

[Chai]

I had the car in the workshop and the mechanic said he had to tighten up the nut at the end of the long bolt as there was some slack. He said that the suspension arms should be under load - wheels on the ground and not up in the air - when tightening that bolt. Either that or the rubbers have compressed since the installation.

[John Green]

He said that the suspension arms should be under load - wheels on the ground and not up in the air - when tightening that bolt.

He is correct, it is a common mistake for workshops and DIYers to tighten everything with it in the air so that the various bushes are then tight in the wrong position. Various inner control arm bushes can fail quite quickly from this.