Discontinuation of 147/156 Bilstein B6 Dampers

[Citroënbender]

Looking for suggestions here.

The backstory - my workshop colleagues politely suggested that the manual 147 should be re-shocked before re-registering (it's a bit bouncy).  I didn't see the point in disagreeing, and bought new genuine strut mounts F&R, plus new front gaiters - all from S4P.  Then from Demon Tweeks, I ordered F&R B6s.  The order was paid down in June, with expectation they'd be posted on some August date.

DT have informed me the Bilstein B6 struts for the Alfa 147/156 models, are gone; I (well, they) have a pair of rears set aside awaiting post but our holding out for the fronts has now revealed this disappointing truth.

So - practical input is requested per ideas for alternative front shocks with 100K+ mileage lifespan; I've been pondering the Koni yellows but not sure how valid their reputation as "leakers" actually is.  Look forward to hearing your ideas. 

[SeleMatt]

That is disappointing news regarding Bilsteins...

Sent from my Moto G (5S) Plus using Tapatalk

[Colin Edwards]

The Koni yellows on my 75 3.0 were installed in 1995 by the original owner -  I have the receipts!  Now due for replacement, they have definitely not leaked.
Had Koni yellows on the 159 for four years with no problems. 

[Citroënbender]

Thank you! Why are the old ones expired? internal failure or breakdown of the oil? 

My 405 Mi16 has yellows, the rears are now weeping slightly and the fronts are OK but stuck on full soft (mate used a rattle gun on them against better advice).  It rides well on standard front springs and the rear torsion bars one notch lower (it's an arse-dragger, ever so slightly).

Also been eyeballing the FSD units, it would be another hundred to upgrade the front pair given my standing credit on the B6s.  It's difficult to get informed opinion on the FSD shocks - the vast majority of comments appear issued from the mouths of BMW-piloting numpties. Tirerack rated them well in a three-way test vs OEM and Yellows at full soft (again, sigh, on a BMW). 

[johnl]

I had front and rear Koni 'Sports' on the old CB7 Accord. After maybe three (or so) years they lost their gas pressure (at least the rear ones did, discovered when I had the springs off to adjust them harder), and a little later all started to leak a bit. They slowly leaked for quite a long time, but despite this still continued to work quite acceptably. This is on less than wonderful rural roads, I'd expect better on smoother surfaces.

I found these Konis to be quite soft at the lower end of the adjustment range, but much better toward 'full stiff'. They were very stiff at 'full stiff'. I'd use them again, I liked them more than the B6 dampers I have on the front of the 147 (comparing an apple to an orange...).

Regards,
John.

[Citroënbender]

Thank you; I hadn't considered loss of pressure as a failure point.

It should be fairly easy to re-gas, but that's an off-the-car job.  Drove the little Pug over the Cattai Ridge Rd and other back ways today, had it largely to myself (westbound) and was noting for a 320000km chassis/motor/box it's not holding up too badly.  Had put the harshness down to hard tyres and fairly low profile but maybe gas pressure in the struts is part of the issue.

[bazzbazz]

As gas struts loose pressure they loose the ability to quickly react to minor road imperfections. Whilst they may still seem to handle well and soak up the more larger road movements they will feel like you are driving on rough road surfaces all the time.

Sound familiar?

[Citroënbender]

Aye, with the loss of pressure in Citroën spheres the ride gets harsher - it first seems counter-intuitive that higher gas pressures mean a softer ride. 

And Bazz, feel free to have an opinion on what to substitute for the unavailable kit.

[Colin Edwards]

After around 140,000 klm and 25 years of use the yellows are very near retirement.  The fronts are about 1/4 turn from full stiff and the rears 2/3 turn from full stiff.  Still a bit underdamped so time for new Koni yellows.  No hesitation in going for Koni again.   A non-adjustable damper will always be a compromise.
Gassing dampers is done to reduce cavitation.  If a damper needs high gas presures (wich introduces heaps of design and manufacturing demands), it usually means the damper is sensitive to cavitation.  Early KYB and Tokico shocks were notorious for this and needed insanely high gas pressures.  Koni have usually gone down the path of low or no gas pressure.

[bazzbazz]

Gassing dampers is done to reduce cavitation.  If a damper needs high gas presures (wich introduces heaps of design and manufacturing demands), it usually means the damper is sensitive to cavitation.  Early KYB and Tokico shocks were notorious for this and needed insanely high gas pressures.  Koni have usually gone down the path of low or no gas pressure.

Yes this is correct, but it is done for more than just this reason.

[johnl]

As gas struts loose pressure they loose the ability to quickly react to minor road imperfections. Whilst they may still seem to handle well and soak up the more larger road movements they will feel like you are driving on rough road surfaces all the time.

Sound familiar?

I have to say no. The ride didn't feel to be adversely impacted by the pressure loss.

As per Colins' comment, it's my understanding that the gas pressure is primarily to prevent cavitation and consequent foaming of the fluid. If that happens then the damper performance deteriorates drastically, but if it doesn't happen then the damper performance is pretty much unaffected (my understanding only). The hotter the fluid gets the more likely cavitation is likely to be, so my experience with de-pressurised Konis not losing significant performance may be that they never got hot enough to cavitate?

What made a big difference was how stiffly they were adjusted. They could be adjusted to be fairly soft or very stiff, the range is huge. The 'Sports' damper adjusters are supposed to only have an effect on rebound stiffness with no impact on bump stiffness, but with the konis on the Accord this didn't seem to be true. On the road they felt much stiffer in 'bump' when set to a stiff setting. This was also the case when I 'manually' pushed down hard on the top of the fenders, i.e. set softly and the chassis would push downward quite easily, but set stiffly it was hard to get any significant movement...

I liked them set pretty stiffly, the handling and steering response was way better.

Like most modern 'shocks', the Konis are 'low pressure' 'twin tube' dampers (not sure what psi is used, but not a great deal). Higher pressures aren't typically needed with twin tube dampers (just to stop cavitation). On the othe hand Bilsteins are a 'high pressure' 'mono tube' design, which require very subsantial gas pressures to work properly (hundreds of psi), not only to control cavitation (not sure exactly why this is, just that it's needed for something other than preventing cavitation alone).

Regards,
John.

[johnl]

Thank you; I hadn't considered loss of pressure as a failure point.

It should be fairly easy to re-gas, but that's an off-the-car job. 

You'd need to add a Schraeder valve, and use nitrogen. Replacing the pressure seals would also be a good idea, given that the old ones will have leaked. A Koni authorised shop will do this for you at considerable cost (and whatever the turnaround time might be?), but apparently they won't sell you the parts to do it yourself as it is (or was?) Koni policy to not do so...

Had put the harshness down to hard tyres and fairly low profile but maybe gas pressure in the struts is part of the issue.

I doubt it. Your first assumption is probably correct...

Have a read of this:

http://farnorthracing.com/autocross_secrets18.html

And this:

http://farnorthracing.com/autocross_secrets6.html

Regards,
John.

[Craig_m67]

This is a really interesting thread.

Worth saying but I expect you've already asked, have you tried other suppliers for the shocks ie. EBSpares, Alfaworkshop, S4P themselves?

I had B6 all round in Sooty (156 1.9JTD SW) - firm as fuck!!
Are B4 still available (OEM I think) or the many versions of KONI

Low mileage sets of B6/B8 or B12/14 often come along secondhand when people scrap(run out of talent) cars - check eBay, incl. ebay UK for new old stock perhaps

Indeed there are several NEW sets available from different sellers >> https://www.ebay.co.uk/itm/2x-Bilstein-B6-SPORT-federtragender-Shock-Absorber-Front-Alfa-Romeo-147-937/183302537591?fits=Car+Make%3AAlfa+Romeo%7CModel%3A147&epid=1238038573&hash=item2aadaec177:g:FHIAAOSwtdpa3k-X

No idea if the price is reasonable or the seller is (in)corrigible
(I've bought parts from UK eBay many times without issues, caveat emptor and all that)

[Citroënbender]

Interesting reading John, but I don't really have a competitive urge. 

I trawled through with an eye to the comments of consistency - and noted multiple references to Bilstein as the author's opined pinnacle of mass-market consistency, followed by Koni.

Craig - I'm in for one lot of postage, DT gave me a week or so (from the 4th) to let them know my choice, before they automatically credit the fronts' price back to my card.  If I buy from someone else I'll be in for double the post effectively.  That said, I'm still sniffing about.  Edit, to note almost any other source of new B6 fronts will mean an extra spend of $200-odd.

Wasn't it EB spares who happily bent over to become collectors for the ATO?

[johnl]

I had B6 all round in Sooty (156 1.9JTD SW) - firm as fuck!!
Are B4 still available (OEM I think) or the many versions of KONI

The B4 is only a 'stock replacement' damper, with close to the stock valving rates. If you want something stiffer than the OE dampers then prepare to be disappointed. I don't know how true this is, but I've heard it said that B4 manufacture is farmed out to some other company, and does not use the same internal high quality components as other dampers in the Bilstein catalogue. I doubt they would be 'bad' dampers, just not true Bilsteins, an attempt to compete with lesser quality (and cheaper) stock replacement products...?

When I purchased my 147 I knew from the test drive that all four dampers would need replacement immediately. I bought four new 'stock replacement' (TRW brand, low pressure gas twin tube like most others). The rear TRWs were and still are quite acceptable (though I would prefer it if they were at least a tad stiffer), but the front ones were bloody hopeless from new. Just way too soft, lacking the stiffness needed to control the suspension and body motion. The ride was harsh because of the rampant suspension oscillation and also 'bouncy', just like the OE ones that I had just binned...

A pair of B6s for the front was a huge improvement, even though I think the B6 rebound valving is still a bit too soft for my taste. If they were Konis I'd just turn the 'knob' clockwise until happy...

Regards,
John.