Changing Brake Discs and hoses on MB Vario
- Thread starter docka
- Start date
docka
Adventurer
Hi Anthony
I bought new discs and pads only, relying on being able to get the hubs back on successfully which it seems I have finally achieved though I've only done about 60 miles since but all appears well. That was to and from the MOT station. It failed as I had not bled the fronts enough as I had to renew the flexible hoses too and there was an imbalance between left and right. Also the rear brakes were binding though I can't understand why as I believe they're automatically adjusting. It may be something to do with the handbrake adjustment but I haven't got my head around that yet, any ideas gratefully received...
Price for both rear discs and pads (non-gen, good fit, seem ok) was £110 delivered, from ebay, mine has the 17.5" wheels and ABS, if you do a search I think they're the cheapest ones on there.
Hopefully you guys can benefit from my mistakes but please don't take this as gospel and don't blame me if it goes wrong, DYOR! If in any doubt, consult a specialist or take to the dealer as it is more than a little disturbing driving something this big and heavy if you're not 100% confident in your work. :snorkel:
After removing the caliper and undoing the cotter pin securing hand brake lever, getting the rear hubs off even with the correct slotted socket I bought wasn't easy, one side required heat from a blow torch, the other i had to drill and chisel through the hub nut itself to remove it.
Once they're off the hub will pull off ok but be warned, they're heavy.
Once hub is removed you will see the O ring remains on the stub axle, take it off, give it a clean and put it back onto stub axle. Then separate hub and disc and you will see the seal between the two which remains in the hub side.
On one side, the large stainless metal washer popped out of the rubber seal, so I took the opportunity to clean the gunk out from the rubber seal and spring within, the other side all stayed together so I just left it. Then I cleaned all loose material off mating surfaces and attached new discs to hubs.
Now the fun starts!
Tried several times to replace O/S hub back onto stub axle as it appears to go on but when you replace hub nut you see it is about 5mm shy of being fully home. Glad I noticed this because it did torque up ok but I knew it wasn't right. Whipped it off again. Inside the hub there are two wheel bearings on my model, and inner and an outer. These appeared out of line with each other so I gently tapped them into square and this time the hub went on ok and I was able to tighten the hub nut fully on. Happy days.
Not so much luck however on the other side.
After many attempts I gave up and left it. In the process I had knackered the O ring so while getting another (£10!) I collared a service technician and asked him what the issue was, why it was seemingly impossible to replace the hub. He said strictly speaking it should be a new hub as the bearings and seals aren't available separately but he told me what the issue is. There's a wee split ring in between the inner and outer bearings that locates them relative to each other within the hub. When you pull the hub off, this dislodges and is practically impossible to replace correctly so I just pinged it off with a screwdriver and removed it. Hey presto, hub slides back on and hub nut goes fully home.
Like I said though, if you are not sure about this you may be better advised to buy a new hub (£250 ish) or indeed if you suspect that your wheel bearings are worn then that may be the better long term option.
Anyway, it's late and I'm recovering from being best man at my brother's wedding so apologies if any of this is unclear, feel free to ask if so
Docka
PS. You will also need to buy 2 ABS rings as you won't be able to remove the old ones from the hub. To refit - they're just a tight fit, I used a hammer and block of wood.
They're about £20 each from the dealer so actually cheaper than elsewhere.
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docka
Adventurer
Hi Ian
Not altogether sure if my previous post helps you much but I think that if the hub is not fully home then there won't be enough pressure on the stainless metal washer (or spigot type plate) to correctly seal the hub up against the shoulder of the stub axle, this could account for the leak as the other side of the seal appears to press against the outer portion of the inner wheel bearing, meaning it is not rotating with the wheel. Just my observations, could be wrong though!
Cheers
Docka
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docka
Adventurer
I'm now having problems getting the brake warning light to go out though I don't have any pad wear sensors fitted at the moment so I was just going to cobble something together...
Are the sensors Normally open or Normally closed does anyone know?
Also the parking brake ℗ light doesn't illuminate despite parking brake working. Anyone any ideas?
Thanks
Are the sensors Normally open or Normally closed does anyone know?
Also the parking brake ℗ light doesn't illuminate despite parking brake working. Anyone any ideas?
Thanks
docka
Adventurer
Ever get the feeling you're talking to yourself? :ylsmoke:
Still trying to resolve this.
Brake warning isn't on when starting engine from cold, the light comes on after the two pressure chambers have got up to pressure. It flickers a bit first and then stays on. Significant perhaps?
I've decided after having another look that the pad wear sensors couldn't cause the light to come on as I've removed them all with the old pads and as they appear to be NO contacts i can't see how their absence would cause the fault...
Still trying to resolve this.
Brake warning isn't on when starting engine from cold, the light comes on after the two pressure chambers have got up to pressure. It flickers a bit first and then stays on. Significant perhaps?
I've decided after having another look that the pad wear sensors couldn't cause the light to come on as I've removed them all with the old pads and as they appear to be NO contacts i can't see how their absence would cause the fault...
docka
Adventurer
Thanks Ian
Even a no-solution response can get one thinking in a different way sometimes!
Think the pad wear sensor is a red-herring so wondering if the parking light not coming on when handbrake is activated and the brake warning light coming on are somehow linked...
Good idea, I'll have a wee scan through the manual, just in case Merc have decided to put some useful information in there...
Thanks
Even a no-solution response can get one thinking in a different way sometimes!
Think the pad wear sensor is a red-herring so wondering if the parking light not coming on when handbrake is activated and the brake warning light coming on are somehow linked...
Good idea, I'll have a wee scan through the manual, just in case Merc have decided to put some useful information in there...
Thanks
docka
Adventurer
It's the same one as shown in the first comment in this thread
http://www.expeditionportal.com/forum/threads/110748-vario-614-warning-light-issue
http://www.expeditionportal.com/forum/threads/110748-vario-614-warning-light-issue
docka
Adventurer
The warning light is a general one, possible faults include brake fluid, pad wear, low pressure and parking brake reservoir pressure.
I am happy however as I think I've found the issue - I went over all the previous work we'd done and one of the copper brake line unions was loose where it meets the flexi hose on front N/S, it's a bit awkward to get to and needed an extra nip up with the mole grips. After that I started her up and the light flickered on momentarily and then went off, I'm hoping it stays off!
Cheers
I am happy however
as I think I've found the issue - I went over all the previous work we'd done and one of the copper brake line unions was loose where it meets the flexi hose on front N/S, it's a bit awkward to get to and needed an extra nip up with the mole grips. After that I started her up and the light flickered on momentarily and then went off, I'm hoping it stays off! Cheers
docka
Adventurer
Update- took the bus for a retest today, warning light remained off - until I had driven about ten miles:snorkel:
Turned round and headed for home again, back to the drawing board. Turns out it was indeed a pad wear sensor.
As mentioned above they are definitely N.O. contacts and the N/S rear sensor socket was corroded across both terminals and when the disc/hub got warm after a few miles it was shorting to earth, hence the warning light. I've now cut all the sockets off on each corner and taped the 2 core wire so it should now remain open circuit.
Retest tomorrow, more confident now...
Turned round and headed for home again, back to the drawing board. Turns out it was indeed a pad wear sensor.
As mentioned above they are definitely N.O. contacts and the N/S rear sensor socket was corroded across both terminals and when the disc/hub got warm after a few miles it was shorting to earth, hence the warning light. I've now cut all the sockets off on each corner and taped the 2 core wire so it should now remain open circuit.
Retest tomorrow, more confident now...
surfer4life
Observer
Well done docka doing this yourself. I had mine done, front and rear by a local garage last year and had the rear calipers replaced and new rear air brake chambers, cost over £1500. I do remember though on the bill that they bought new wear sensors and when i asked him he said that they always replace the sensors as they be temperamental if messed with i.e changing the pads.
docka
Adventurer
Thanks surf, pretty chuffed I've done it myself and learnt a fair bit in the process, hopefully of use to others too...
Yes I wasn't too keen on just snipping the ends and taping them back but it's done the trick for now, will get some replacement sensors and cables ordered soon...
Need some new tyres next as current ones are starting to crack and perish a wee bit.
Yes I wasn't too keen on just snipping the ends and taping them back but it's done the trick for now, will get some replacement sensors and cables ordered soon...
Need some new tyres next as current ones are starting to crack and perish a wee bit.