Mercedes Brakes

Have you had problems with brakes on your Mercedes AS?

I'd driven Sprinters occasionally over the years and had never been too happy with the feel of the brakes although they always stopped me.

When I took delivery of the Malvern in October 2011 the brakes were ok.

September 2015 MOT (23,036m) reported Rear Brakes imbalanced requirements only just met. MB commercial vehicle workshop in Stoke asked to investigate in January 2016. They replaced FRONT disks etc and reported all ok.

June 2016 in Germany a caliper on offside rear disc seized causing overheating to disc and wheel. Recovered to a truck recovery workshop. They stripped, cleaned and lubricated rear brake and handbrake assemblies. MB had never had rear wheels off so they'll never see the van again! Brakes seemed ok for about three months but then lost 'feel'.

September 2016 MOT (30,488m) reported parking brake just met 16%. January 2017 had my local workshop strip, clean and lubricate all discs and parking brake.

By autumn 2017 neither foot or parking brakes felt 'right'. September 2017 MOT (36,459m) reported rear brake disc worn, front brakes imbalanced requirements just met and parking brake imbalance requirements just met. My local workshop stripped, cleaned and lubricated front discs and they seem to operate ok now. The lining parking brake shoes was breaking up, the drums scored and discs shot so the disc/drums, pads and shoes have been replaced.

I've only driven the van back round the corner so need a few miles for the brakes to settle before commenting on success (I hope) of the repairs.

Hi Peter
    my  brakes seem OK.It had a service and MOT with MB last year The MOT was done with  ATS this year special price £35 ,I intend booking a service with MB for early next year,but saying all this I find the handbrake struggles to hold the van on a slope note van and trailer about 5 ton.I remember on a car service that it did not include adjusting a handbrake!! I think modern servicing means looking and checking not actually doing anything.I do not have a garage local that I feel I can trust
Regards
Alan

My brakes work how I would think they should work. You say all drums discs pads and shoes replaced do you mean discs and pads replaced as I thought yours would be like mine disc all round

Hi Chris
   I think that they are disc's all round but the rear disc's have a built it drum for the handbrake mechanism
Regards
Alan

That's correct with shoes inside the drum and pads on the disc

Peter Brown wrote:That's correct with shoes inside the drum and pads on the disc

Live and learn clever them Germans

I did have to have the discs replaced very early on in the life of my auto MB Worcester. My trusted garage was very surprised as they normally reckon on needing to change five sets of pads before the discs need renewing.
I put it down to my van having been stored outside for some time prior to a January delivery resulting in the rust setting in and then flaking occurring.
Other than a squeak from a minor bind on the handbrake, I have not had any subsequent problems since then (five years) and hope not to have in the immediate future or at least until I return from Mull from where I am sending this response!

Regards Graham

Hi Peter I have not owed a merc of your variety but I would look to make on next inspection to change fluid in breaking system and change bleed nipples  or what ever the merc  has in case you have air entering the system. 
Geof

No problems with brakes on ours at all in five years since new.

The reason that handbrakes normally (there are exceptions!) employ drums is basic physics: when brake components (alloy calipers, friction pads and cast iron discs) become hot they expand. Imagine the situation where your brakes are hot, say after a long hill descent and you then stop and apply the handbrake on a slope. The thickness of the disk (and the pads, as they also expand) will be slightly more than if cold, so if you were to apply a handbrake onto the discs, as they cooled the disc would become thinner and the effective pressure applied by the pads would be less and there is a danger the van would end up in the river at the bottom of the hill. Oh dear.

With a drum, as it get hot so the diameter of the drum becomes larger- apply the handbrake, as the drum cools the diameter becomes less, so the pressure exerted by the pads actually increases! Happy days.

One clever exception I have had experience of is the Bentley Continental GT, a 2-tonne, very fast car- the brakes can get seriously hot yet the handbrake operates only on the disks; how they have overcome this is for the handbrake to self-tighten several timesfor a period after the car is parked- in other words the handbrake pulls itself tighter as the brakes cool down. Expensive!

My Lotus Elans (the olde-style from the 60s) have discs all round but have separate handbrake pads, which are held slightly off the disks by springs, therefore do not get hot whilst running; this is supposed to mean that as the brakes cool down the handbrake will stay tight. Hmmmm.... I always leave it in gear because the design of the handbrake linkage is not the world's best, from an engineering point of view.

The handbrake on our Stanton certainly needs a good tug to hold it on a hill (it's an Auto, so should be held by P but I put it into N once just to see how good the brake was when fully laden).

I have just replaced all 4 discs , pads and handbrake shoes on my brother in laws mercedes sl500 and worryingly the service done just a few days before while highlighting discs requiring replacement shortly did not pick up the fact that the ferodo friction material was detached from the pad  metal back plates on all 4  pads of the back brakes. Apparently they do not remove wheels and only  inspect through the holes in the alloys. On a car capable of 155mph! Gone are the days when wheels removed at every service- took 2 hours to remove alloy wheels from neighbours car at 4 years old with full dealers service history. Wheels welded with corrosion to hubs ,  obviously had never been off the car before....problem is your average yoof while adept with the laptop has not learned the basics to be called a mechanic , more a 'fitter'.....

No problems with mine Pete....I got rid of the Mercedes and went back to Peugeot...awesome! lol

On some sprinter PSVs that are not worked hard softer pads were fitted to improve braking. They often fail on bad performance of rear brakes. Harder pads tend to glaze with light use or a vehicle that is driven well like a motorhome. Try Mintex or Ferodo

As per another thread the stated content of Halfords autocentre service plans specifically includes removal of road wheels for inspection. Presumably because it is general and not vehicle specific so it covers those that do require it. Main dealers seem to grab every opportunity to reduce their costs so if the manufacturer says don't need to remove the wheels they won't.

My previous vehicle had the drum inside a disk type handbrake. Because the shoes might never have friction contact the defined fix for low handbrake efficiency was to drive it for a short distance with the handbrake on.

I would look at getting the fluid replaced entirely preferably under pressure.

Peter Brown wrote:

I've only driven the van back round the corner so need a few miles for the brakes to settle before commenting on success (I hope) of the repairs.

I've now done about 100 miles. The brakes are fine at the moment, certainly no problem with the brake fluid.