Hi guys … i have a question for the mechanics out there … i am the proud owner of an old 1996 mercedes 814 7.5 tonne removal truck which i am very happy with … it has just recently failed its annual roadworthy test on a leaking rear brake chamber ( air ) the air leak is only happening when the hand brake is in the off position and the leak seems to be around the metal clamp near where the hoses go in …(the metal chamber is badly corroded at this point) the brakes passed on the rolling road 100% ? … has any one had any experience of repairing these units and or can you guys point me in the right direction to get a second hand replacement unit … i live in Northern ireland and there is a lack of commercial breakers in my area … does anyone know are they hard to replace ? any tips on how to get them off and if a repair is possible … on a bit of a budget with this … regards in advance jack …
Whatever you do do not fiddle with the band or dismantle the chamber also be very careful if it’s badly corroded. The chamber contains a spring that can unleash lethal force.
To be honest, even if it turns out the original part is hard to come by I would think it more than likely it would not be too difficult to engineer a solution with something similar.
As above do not tamper with a brake chamber. The spring inside is the same size as a coil spring on a cars suspension. It is compressed and contains a lot of force. The banding round the middle holds the 2 halves of the chamber together which contains this spring. TAKE CARE
cyberjack:
Hi guys … i have a question for the mechanics out there … i am the proud owner of an old 1996 mercedes 814 7.5 tonne removal truck which i am very happy with … it has just recently failed its annual roadworthy test on a leaking rear brake chamber ( air ) the air leak is only happening when the hand brake is in the off position and the leak seems to be around the metal clamp near where the hoses go in …(the metal chamber is badly corroded at this point) the brakes passed on the rolling road 100% ? … has any one had any experience of repairing these units and or can you guys point me in the right direction to get a second hand replacement unit … i live in Northern ireland and there is a lack of commercial breakers in my area … does anyone know are they hard to replace ? any tips on how to get them off and if a repair is possible … on a bit of a budget with this … regards in advance jack …
any Pics?
partsbase.org/parts/mercedes-a0014319814/
buycarparts.co.uk/mercedes-b … r-mounting
da one may have parts for you too.
ebay.co.uk/itm/MERCEDES-VARI … 0730265092
Computer says 61275w in Wabco or bs7309sp in Knorr Bremse but parts place will be able to tell you for sure.
Immigrant:
partsbase.orgda one may have parts for you too.
ebay.co.uk/itm/MERCEDES-VARI … 0730265092
Vario 814 won’t fit an 814
THANKS GUYS FOR ALL YOUR HELP AND ADVICE 
… I HAVE WOUND OUT THE BIG 24MM BOLT AT THE BACK OF THE CHAMBER THUS COMPRESSING THE HEAVY SPRING THAT U GUYS WARNED ME ABOUT AND LETTING ALL THE AIR OUT OF THE SYSTEM I UNDONE THE AIR HOSES AND THE CLAMP …I NOW HAVE THE BRAKE CHAMBER OFF THE TRUCK AND CAN SEE THE ALUMINIUM CASING IS WASTED AND ROTTEN, THE UNIT HAS REACHED THE END OF IT’S USEFULL LIFE AND I AM GOING TO TRY TO SOURCE A REPLACEMENT CHAMBER …THE CHANCES OF GETTING A GOOD SECOND HAND UNIT THAT IS IN BETTER SHAPE THAN MY OLD ONE IS DOUBTFUL… MY LOCAL COMMERCIAL MOTOR FACTORS CAN ORDER ME UP A NEW DIAPHRAM ( ALTHOUGH THE OLD ONE LOOKS OK ) BUT THE NEW UNIT IS £414.00 PLUS VAT ! SURELY I CAN GET A NEW /OLD STOCK ONE CHEAPER SOMEWHERE ? PERHAPS THEY USED THIS CHAMBER ON OTHER TRUCKS ? JUST TO BE CLEAR THE LORRY IS A 7.5 TONNE DIESEL 6 LITRE LUTON BODY FURNITURE VAN AND NOT THE SMALLER VARIO MODEL … ONCE AGAIN ANY HELP IN SOURCING ONE WOULD BE MUCH APPRECIATED 
I HAVE SOME PICS OF THE OLD UNIT WHICH I WILL PUT UP AS SOON AS I FIGURE OUT HOW TO DO IT LOL …
Is this what it looks like by any chance
cyberjack:
THANKS GUYS FOR ALL YOUR HELP AND ADVICE
It will probably be common to other vehicles (not the Vario which is the bonneted panel van type thing) but to be honest you were always going to be into £300+ for a new drive axle chamber. It might be possible to fit a similar chamber, not designed for it, but I wouldn’t if the correct part is available unless there’s a known tried and tested substitute out there. You often need spacers or adapters to avoid overstressing the caliper which ends up wrecked otherwise. As per my original post I would only consider this route if the correct part was totally unavailable.
Try proper German ebay.de or Polish ebay (allegro.pl) would be my advice. Ringing round a few parts factors might get it down £100 or so if someone’s got one that’s been warming a shelf for a while. Otherwise just bite the bullet and put a new one on, the truck’s not earning if it’s off the road.
Don’t want to sound like a holier than thou finger wagger but if you’re running trucks you’re supposed to have contingency funds to cover safety critical repairs and it sounds like this chamber should have been swapped out long before it got on the rollers at MOT time.
Fit the correct genuine part as a service exchange unit obtained at the best price offered and you will have something that works properly 1st time and will pass the retest. Ebay, 2nd hand etc - it may be OK or it may not be, keep clear of Far Eastern manufactured parts. The tester will probably do another roller brake test which ‘another’ brake chamber may fail meaning yet another trip back to the test station.
IIRC Mrec used an early Voss type fitting (series 230?)for the air pipes which included a seal which often stayed behind in the air port, make sure you recover this or fit new otherwise the pipe unions will leak.
The 814D rear brakes were vaguely similar to the dreaded Stopmasters unless I am very much mistaken. The Chamber screws into the brake anchor bracket and bisector and is locked in place with a large serrated nut. I think that the way to go is to renew the whole lot - which ought to be how it comes as an exchange unit anyway - rather than mess about with a 20 year old band clamp and corroded diaphragm housing.
Swampey2418:
0Is this what it looks like by any chance
…Nothing like it chum … it is not a vario van !
cyberjack:
Swampey2418:
Is this what it looks like by any chance…Nothing like it chum … it is not a vario van !
You got any pics yet ? what about this bad boy ?
No chum that is not it either … this is a a pic of the old unit … sorry about the quality … as u can see it is ■■■■■■ ! 
Swampey2418:
cyberjack:
Swampey2418:
1Is this what it looks like by any chance
…Nothing like it chum … it is not a vario van !
You got any pics yet ? what about this bad boy ?
0
As Roy Walker would say ‘it’s a good guess but it’s not right’.
cav551:
The 814D rear brakes were vaguely similar to the dreaded Stopmasters unless I am very much mistaken. The Chamber screws into the brake anchor bracket and bisector and is locked in place with a large serrated nut. I think that the way to go is to renew the whole lot - which ought to be how it comes as an exchange unit anyway - rather than mess about with a 20 year old band clamp and corroded diaphragm housing.
Not sure it is but’ I’ve certainly had all sorts of fun and games with that type over years - have no idea why anyone thought that castellated collet locking ring affair was a good idea.
I do remember going through a phase of trying to remove them properly with all sorts of hook wrenches on the collet nut and chain wrenches on the chamber only to finally arrive at he most efficient method of smacking them where the airline mounting is with a lump hammer.
cyberjack:
Ok, it looks like you’ve left the service brake part of the chamber still bolted to the truck. Is that part fundamentally ok corrosion wise and it’s just this part of the chamber the issue is with?
Finally think I’ve got it… one of these
