Uprated front anti roll bar C124 3.2 sportline

[Scooby220]

Hi,

Just changed all for shocks and was about to the replace the front anti roll bar bushes.

Then noticed the original bar has worn away near the bush areas.

Apart from replacing with an OEM sportline bar does anyone offer a thicker bar ?
Have looked at Eibach and other brands but nothing available.

Thanks in advance

 

[hotrodder]

Dunno who if anyone does uprated bars for them. Probably already know this but the front anti roll bars do have several tapered & thinner sections by design and are supposed to be thinner near the location of the outer bushes. The bar does wear under the bushes but you really need to remove the old bushes to discover how much it has

http://www.w124performance.com/images/W124_sway_bars/124_swaybars.pdf gives the diameters of various different bars, obviously Septics don't do twisty roads so might(?) be wrong in other areas for European models as well as calling them swaybars. FWIW based on bush part # in that pdf my '93 320te sport chassis has the bigger 28.5 / 19mm front bar that they only show for a sportline convertible and LWB/limos. I believe (maybe wrongly) that Eibach 'uprated bars' were 28mm when they were available?

New antiroll bar bushes was one of the first things i did when i bought it, didn't measure how much wear the bar had but it was enough that new bushes maybe slid on a bit too easily. Still transformed the old barge

 

[Scooby220]

hotrodder,

Cheers for info and had a look but no aftermarket bars available from anyone.

Was told either to go for a W124 E500 or a cabriolet sportline bar as they are a bit thicker. Gonna pop in to my local dealer and see what the prices are.

 

[Bellow]

Why do you want a thicker front bar?

 

[bolide]

I believe the 6-cylinder ARB is not the same shape as the V8 one so an E500 one wouldn't work. There is evidently a limo bar that fits

I'd be very interested to hear how a thicker ARB changes the car. It'll be a trade-off, as always

Nick Froome

 

[hotrodder]

As Nick said anti roll bars are a different shape on V8s. Wouldn't be surprised if some people have modified things to fit them to 6cyl cars and even w201s but they aren't necessarily much of an 'upgrade' over a sportline bar based on the numbers... the middle section that works like a torsion spring is within + / - 0.5mm of sportline & limo bars, the outer ends (effectively the levers for the torsion bar) don't have a tapered section which'll make it a little stiffer

According to the link i posted a sportline e320 cabriolet bar is the same as a 'limo' bar. Like i said based on part # for the roll bar bushes* i bought from MB my 320 estate has the same anti roll bar. They were ordered based from the VIN# so it hasn't been modified/fitted with a thicker bar at some point

Why do you want a thicker front bar?

Why do people fit massive wheels or bodykits stick on tat? Granted a thicker ARB doesn't make a car look 'better' but it's not likely to ruin the driveability as much as slamming the thing on spine shatteringly hard suspension and resorting to stretched tyres 'cause the wheels are too big to fit and soooooo heavy they further ruin the ride and handling

Might be wrong but i reckon a slightly stiffer front bar could add more than it detracts/messes with balance... with new front ARB bushes turn in was better i.e. didn't feel like it was 'falling over' onto the outside front as much and the front would wash out less too. They're fairly neutral old barges (understeer on a trailing throttle or over driving the thing, drive through a corner and the front end behaves itself) so as long as a massively stiffer bar isn't fitted i wouldn't have thought untameable understeer would result?


* I've just dug out the invoice, a124 323 46 85 and a124 323 51 85 although the latter (outer bushes) look to be common to several bars. If i remember and it's not peeing down all day i'll mic the bar tomorrow

 

[coupe addict]

Thickness is only one characteristic of an arb. The profile of the outer ends involves, for most 124 models, changes in thickness which are intended to affect the dynamic response of the wheel. The sportline 320 coupe arb is one of those 'no expense spared' mb jobs which has you looking at the bar and wondering if there could be any way that the engineers could have made its manufacture more difficult - but there is a reason for all that expensive turning.
It is not beyond possibility that the wear seen by scooby220 is at least in part the original profile, turned smaller at the outer bush. I really do not believe that making any sort of change to such an insanely carefully engineered component is likely to be beneficial.
BTW if you replace the inner bushes use loads of french chalk or something similar to slide the bushes round the bends - I pulled a patch of skin clean off the palm of my hand doing that little job - although I am admittedly a bit of a wimp.

 

[Scooby220]

Just wondering what was out there in terms of a thicker roll bar and yes it's trial and error at the end of the day.

I've just finished replacing all four shocks and new top mounts, so trying to get back the car's precise handling as it left the factory the day it was built.

The car is nearly 23yrs old and I'm sure most of the suspension components are worn out whether its a standard chassis or a sportline.

A new roll bar from dealer is £232+VAT and no one else seems to stock them for the W124.

 

[hotrodder]

£232 + VAT is pretty good value, i thought they'd be more than that these days.

Measured the ARB on mine today and it's definately 28.5mm* which suggests to me that maybe all European 320 sport chassis 124s got the "limo" bar and the Septics got a softer set up on most models?

Scooby, as bushes should be peanuts (fiver or so ea?) i'd replace them before buying a new bar. Even if the bushes have worn the bar a little it should make a pretty noticable difference to the way the car drives

* it actually measured 28.62mm just inboard of the inner bushes probably due to paint & tolerances etc. Couldn't reach the tapered ends properly and unlike the middle of the bar there's some surface rust both of which explain me getting a measurement of just over 20mm

 

[grober]

One thing about fitting a stiffer antiroll bar on the front is that you will alter the front roll stiffness relative to the rear unless you uprate that too. This may be OK if the difference isn't too great but it may alter the handling

 

[Scooby220]

hotrodder,

I've got a complete ARB bush kit going on and new brackets, I've already fitted new suspension top mounts.

Do you happen to have a part number for the roll bar to see how much that will be ?

Next on the list is a complete rear suspension link arms kit to be done

 

[Bellow]

A thicker front bar will increase the tendency to understeer. An odd choice.

 

[hotrodder]

Against the clock around a track or driving as fast as possible around concentric circles at longcross etc i agree a larger front ARB would probably lose. Personally i don't (usually) lap roundabouts to see how fast i can go before the front starts washing out... 124s are big wafty barges not track day toys (without lots of other suspension mods), there's a big roundabout near me i use fairly often and late at night/when it's quiet i've found myself hitting 35+ ish mph around it without terminal understeer setting in. Way more body roll than is comfortable though...

Relatively too much front ARB = more corner entry understeer which gets worse no matter you try with the exception of hooliganism i.e. lifting off and then stamping on the throttle [/gross generalisation and tongue firmly in cheek]

hotrodder,

I've got a complete ARB bush kit going on and new brackets, I've already fitted new suspension top mounts.

Do you happen to have a part number for the roll bar to see how much that will be ?

Next on the list is a complete rear suspension link arms kit to be done

Gotcha. Part # for different bars and bushes are in the link i posted. What are the part # for the bushes MB sold you? They should give a clue as to what size ARB is currently fitted

Granted there's a fair few of them but IIRC Lemforder rear links can be got for around £20-£25ea? FWIW when i bought some Lemforder front top mounts from Autopartstechnik aka Midland car spares they had an MB part # cast into them and some poor sod had the job of sanding off the MB star logo that precedes the #
The one i'm not looking forward to is new front LCAs... Lemforder don't do the later one piece type (with welded in ball joints to clear larger brakes on the 320 etc) and as far i've been able to work out no one else does anything of decent quality. Sportline lower control arms from MB are ~ £440 ea