Merc Sprinter Seat Upgrade &Rear Suspension

Yes, I had thought of that but could not get my head round how a 4 year old van with just 5000 miles on it could have such worn springs?...may have to look at a local place to have them removed and re tempered?....

Getting somewhere now 

If you can see your part numbers Big'nuf we will have a starting point and also the weighbridge axle weights will be important.

Just got this from Merc Hull. Interesting that he should say C38 not as heavyweight duty 

The part numbers are as follows.
 
C33 = 906 320 34 06 (these are fitted to your vehicle)
 
C38 = 906 320 82 06 (not as heavy duty as C33)

Has anyone had self levelling and / or air suspension fitted??

Jaytee wrote:Getting somewhere now 

If you can see your part numbers Big'nuf we will have a starting point and also the weighbridge axle weights will be important.

Just got this from Merc Hull. Interesting that he should say C38 not as heavyweight duty 

The part numbers are as follows.
 
C33 = 906 320 34 06 (these are fitted to your vehicle)
 
C38 = 906 320 82 06 (not as heavy duty as C33)

Big'nuf previously posted that he has twin springs 906 320 49 06, with a build spec C33, so that is 5 part numbers now?

MB options says C38 specifically for 3880kg, ie heavier but does that mean heavier duty?

Hi Peter, I haven't read back through but I thought it was the garage that told him what part number he has?  Cannot get my head around the different C33 specs for the same year of vehicle, just doesn't make sense which is why I am still wondering if he has the correct springs. If he could read the number off his springs I could ask Merc Hull what they are. I have searched the web for the part numbers but Merc seem to keep that close the their chests. The Daimler USA market seem to have different items per the same spec #'s.

Sorry Big'nuf sounds like I am writing as if you can't see the post.

Jaytee, Big_nuf wrote yesyerday at 8.25pm, identifying his twin spring part number and that it was supposedly C33.

OK, I definately have the two-leaf springs. (2 leafs on each axle). Both are curved, so no "helper springs).

MB tells me that the original would be "C33" (also as my build sheet states).
MB tells me that could have been a choice of two; 906 320 75 06 or 906 320 49 06
I have 906 320 49 06 fitted on mine.
(Used a mirror and torch - real clear and easy to see)

MB parts at Gloucester tell me that this one will have now been superseded by 906 320 87 06
(If you can believe a word they say?...)

From what I can gather, they are all rated up to 3.5T (The C33 being a harder type specifically for motorhomes)
It has been suggested by several spring manufacturers to replace them with the 5T equivalent....
My mechanic says that would make too hard a ride and the van would bounce all over the place.

Im going to stick with what I have and rely on the air bags...experimenting with different pressures as I go.
I will not hold my breath the ride will ever be as good as any of my previous M Homes....

It does seem inordinately complex for what should be straight forward.

All different numbers to those given to me by Merc Hull Commercials 
I will get the actual part number off mine see if it is the number they said it is and then report back and give up .
If only we could access the MB master parts listing to suss it all ourselves.

Jaytee wrote:All different numbers to those given to me by Merc Hull Commercials 
I will get the actual part number off mine see if it is the number they said it is and then report back and give up .
If only we could access the MB master parts listing to suss it all ourselves.

John,
I have given up already - Doubles, Twins, Two Springs, Helpers, etc. ...... .and the possibilities list appears to go on and on. 
Mine is now working how we like it - so, .. "if it ain't broke don't fix it".
Liam

Liam wrote:

Jaytee wrote:All different numbers to those given to me by Merc Hull Commercials 
I will get the actual part number off mine see if it is the number they said it is and then report back and give up .
If only we could access the MB master parts listing to suss it all ourselves.

John,
I have given up already - Doubles, Twins, Two Springs, Helpers, etc. ...... .and the possibilities list appears to go on and on. 
Mine is now working how we like it - so, .. "if it ain't broke don't fix it".
Liam

As is mine now Liam    but this is a bit of a challenge   Not quite sure if Big'nuf finds it so 

Have checked mine and they are C33, single leaf and the part number 'is' 906 320 34 06, it rides well (seriously nippy overtakes without fear or dread, except for SWMBO who insists on screaming) and 70 odd on motorways comfortably under control and is heavier than Big'nufs truck.

So, mine is as per spec and as advised by Merc Hull Commercial.  Why then are all these other spurious specs and part numbers being bandied around by various dealers for the same year of Sprinter?  Or is Big'nufs chassis different?  OR has he got the wrong springs 

Hello all, I'm with Jaytee on this one! C33, single leaf, part number 906 320 34 06.
Not noticed any problems with handling.
Apologies for rubbish camera-phone  picture.

Strooth, I thought aircraft maintenance was complicated but it's got nothing on Sprinter rear springs 

Just been chatting (or annoying depending on your view) Merc Hull Commercials parts department  .

Looking back through this whole thread Big'nuf has 906 320 4906 rear springs fitted. Posted 4th April @08.25.  These were superseded by 8706 springs from 28/9/12. As far as the parts chap could determine from his listing this is a standard 906 Sprinter spring and again as far a he could determine is definitely NOT a C33 spring which is a 906 320 3406. 

So, I reckon you have the wrong springs fitted, but there again 

I now need to go and lie down 

Ps will still be good to know your axle weight on the weighbridge and make a note of what's in the van I.e full or empty water, fuel etc.

Gents...
Very interesting call received today from Autosleeper..and really helpful, Im thinking.

Firstly;
They claim they do not touch or alter any springs or suspension and only work off whatever Mercedes supply to them as a chassis. He sees my handling issue is purely down to having the Air-Ride air assist bags fitted. They are not approved by Mercedes or Autosleeper and apparently will wrestle constantly with the sensors and computers that run the van suspension.
He suggests I immediately remove them and have the coil springs refitted. He claims the ride will be faultless and like driving a different van.
He is arranging with the local AS dealer (Marquis) to inspect my leaf springs, clarify they are the correct ones and advise me on removing the air ride.
He also insisted if I needed air bags, to only have VB bags fitted as they are the only ones approved by them and are worth every penny of the £4K..... 
Well Im thinking...Do I really need air bags?...I do not carry any great weights, I only tow.
If removing the airbags improve it then awesome....
Your thoughts or experiences?

Secondly:
He also clarified that you can definitely have a tow bar fitted to most Merc based vans, it is not illegal and you can tow as long as its within the GTW. Even though I have no GTW on my AS plate - He says it is still legal.

Thirdly...
He also agreed there would be no issue having my weight uprated from 3200 to 3500 and agreed SVTech were the boys to do it (at the usual cost) and they would re issue the AS plates with a GTW on it.

If this all pans out as he says then I can only say what a really helpful and informative company Autosleeper are.
Im impressed so far - but time will tell? lol

Will keep you informed. Les (B16NUF)

It will be interesting to see how Marquis decide if you have the correct springs on or not. 

I managed to get my spring number today, 906 320 34 06/Z002, same as Jaytee.

I have emailed MB at Milton Keynes HQ, and asked for the part numbers for C33 and C38, and if XL8 weight upgrade changes C33 to C38. Will report if I get a reply.

big'nuf wrote:
He suggests I immediately remove them and have the coil springs refitted. 
He is arranging with the local AS dealer (Marquis) to inspect my leaf springs, clarify they are the correct ones and advise me on removing the air ride.

Looks like you have got someone at AS listening at last - lets hope it turns out successful!

Re "Coil Springs" - are you saying that you have coils in addition to the longitudinal Leaf springs? Don't have any on my rear suspension!

I guess all that Marquis can do is a compare and contrast of your suspension with another of the same type they might have in stock.

All the best,
Liam

PLOUGHLIN wrote:I managed to get my spring number today, 906 320 34 06/Z002, same as Jaytee.

I have emailed MB at Milton Keynes HQ, and asked for the part numbers for C33 and C38, and if XL8 weight upgrade changes C33 to C38. Will report if I get a reply.

Ploughlin,
For your info - see below the answer I got from the Auto Sleeper Homologation Dept. when I was querying the suspension build standard for my van.

....
 
Yes, XL8 would be part of the spec for the Malvern.
 
Regards,
 
Peter Kingsnorth
 
 
 

 
Peter,
A further question - would it be possible please to confirm that the code XL8 – Weight variant 3880kgs also applies to these Mercedes Chassis? – in my case a Malvern (........ build number – ..........  
 
Thanks,
  

 
 
See below extract from a recent e-mail on a similar topic.
 
The sales team have told me that the chassis we order in for conversion have the following 1. C33- Uprated rear springs 2. C43- Uprated rear axle stabiliser 3. C45- Uprated front axle stabiliser 4. CE6- Suspension stability. These are the only differences regarding the chassis so I hope it is of use.
 
Hope this helps.
 
Regards,
Peter Kingsnorth
Homologation Engineer
Auto-Sleepers

Liam, I understand what AS are saying, but am not sure they actually know what MB supplies them with.

C33 is described by MB as twin leaf harder springs, which is what Big-nuf has (3200kg van).
C38 is described by MB as uprated single spring for weight upgrade to 3880kg (XL8). Everyone so far with the weight upgrade has single springs (906 320 34 06),

Question is does specifying XL8 override specifying C33 and lead to fitment of C38 by MB?

PLOUGHLIN wrote:Liam, I understand what AS are saying, but am not sure they actually know what MB supplies them with.

C33 is described by MB as twin leaf harder springs, which is what Big-nuf has (3200kg van).
C38 is described by MB as uprated single spring for weight upgrade to 3880kg (XL8). Everyone so far with  the weight upgrade has single springs (906 320 34 06),

Question is does specifying XL8 override specifying C33 and lead to fitment of C38 by MB?

AS may not be too aware of what they actually get delivered to their yard but the specification they ask for is as described by their Homologation Dept. above and indeed this stacks up exactly with the vin build description for my vehicle - which indicates XL8 Weight variant 3880kg and this includes, C43 & C33 (Rear Spring Harder) but no mention of C38!

I think we have already concluded that the German Technical Translation into English may not be perfect - when referring to singles, twins and and plurals - I.e. you will have seen that their Equipment Book Description Code refers to C33 Rear Springs Harder whilst my Vin. build describes C33 Rear Spring Harder - no S after spring!!! 

Liam

Hi Folks,       (  Big'nuf wrote, )

Secondly:
He also clarified that you can definitely have a tow bar fitted to most Merc based vans, it is not illegal and you can tow as long as its within the GTW. Even though I have no GTW on my AS plate - He says it is still legal,

Les, please could you let me know who your Auto Sleeper contact is, ( a PM if you wish ) as I am still awaiting for confirmation from them regarding Towing legality.

Regarding rear suspension, when we first got our Bourton Feb 2016 we found the ride very hard, but handled well, I reduced the rear tyre pressures to 60 psi and now fide the ride satisfactory, I will check spring numbers as chassis build date August 2014.
Thanks for an excellent forum.
Regards
Alan

Wellsgofar wrote:I reduced the rear tyre pressures to 60 psi and now fide the ride satisfactory,

I would just caution that when I experimented with tyre pressures on my Mercedes I found that when fully laden and at 70mph, 65psi was too low and made the van feel unstable - it didn't reduce any rattling either.

If you run the van light and at lower speeds it may be acceptable, but do note that MB require a motorhome conversion to be operated with maximum recommended tyre pressures.

Many thanks for your reply Peter, I'm mainly lightly loaded on 60 psi, except when towing, when I up the pressure to recommended 65 psi.
Regards
Alan

PLOUGHLIN wrote:Liam, I understand what AS are saying, but am not sure they actually know what MB supplies them with.

C33 is described by MB as twin leaf harder springs, which is what Big-nuf has (3200kg van).
C38 is described by MB as uprated single spring for weight upgrade to 3880kg (XL8). Everyone so far with  the weight upgrade has single springs (906 320 34 06),

Question is does specifying XL8 override specifying C33 and lead to fitment of C38 by MB?

Peter, I have a feeling that the two leaf C33 is only the American Daimler Benz market which is the booklet you have been referring to, the European C33 is single leaf with the part number previously proven.

You could be right or not?

Liam...i think you are right...It seems like they remove the Merc bumpstop to fit the air assist bag in its place..not a coil spring. 

Jaytree...Whats the difference in american and european ones?...how can you tell the difference?
Ive just checked the build spec and it says Mercedes Benz, Euro Sprinter?...(with C33)

Wellsgofar...I have already lowered the tyre pressures by 5psi each (Rears) - no change....will put them back to 65 as in MB handbook.

big'nuf wrote:Gents...
Very interesting call received today from Autosleeper..and really helpful, Im thinking.

Firstly;
They claim they do not touch or alter any springs or suspension and only work off whatever Mercedes supply to them as a chassis. He sees my handling issue is purely down to having the Air-Ride air assist bags fitted. They are not approved by Mercedes or Autosleeper and apparently will wrestle constantly with the "sensors and computers that run the van suspension".
He suggests I immediately remove them and have the coil springs refitted............................................
Will keep you informed. Les (B16NUF)

Having been up and down the Mercedes vs. Auto-Sleeper rear spring road a couple(!) of times (readers with long memories might just recall the saga of the Euro-spec vs UK-spec, what I ordered vs what I got  fiasco) I have tried to keep out of this discussion recently; just when I thought that I knew all the 147.5 variations of spring/damper/anti-roll bar/bump stop variations... we now have coil springs introduced to the mix!

Who, exactly, at A-S said this to you?

As for the "sensors and computers that run the van suspension"; well... I've read about the cross-wind assist and all that other hokum. I've crawled under the van more than once(!!) and found a couple of cart-springs and a pair of simple dampers.

Having, eventually,  come to a solution (semi-air rear suspension), whereby A-S, the supplying dealer and myself split the cost three ways, I now have a van which handles to a more than acceptable level. It really is a shame that A-S chose (back in 2014) to advertise a product with "upgraded" payload, which consisted of a paper "upgrade" (that they failed to supply to me) EU-spec chassis; rather than an off the shelf engineering solution in the form of the heavier duty suspension components which were standard in the UK.

Would I recommend A-S to a friend who was looking to sink their life-savings into a 'van?