Pressurized
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I'm in exactly the same boat as you. Please let me know if you have any success with this courtesy replacement and I'll do the same for you!
Good luck
Engine Plate Corrosion
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Good luck
Thanks for the lead Gavin. Is there any issue with the lower tensile strength of s/s bolts for the disc bolts?
gavin@iow
Registered user
There is no problem with the stainless disc bolts, they are in 'shear' rather than 'tension'.
Thanks. I have ordered some. The torque schedule that I downloaded (www.r1200gs.info/misc/torque.html) gives 24Nm - but says that the screws are 'micro-encapsulated' - what does that mean? Did you use any Locktite?
steve16
Guest
Bolts...
....so new bolts look the way to go...........
could someone just confirm the size and best place to get them.
Still think dealers should change all these free of charge until BMW manage to sort this problem out.
Cheers
Steve
....so new bolts look the way to go...........
could someone just confirm the size and best place to get them. Still think dealers should change all these free of charge until BMW manage to sort this problem out.
Cheers
Steve
Gros Buck
Guest
Hi
having hoped my bike wouldn't succumb, today I noticed corrosion bubbles behind the paint on the front engine plate around the black plastic cover.
I'm assuming this will be corrected by BMW under warranty (bike new in May 2005). Anyone had any trouble getting them to agree this?
I'll have to go to a different dealer, the supplying dealer (Prestige) no longer being in existence. Will this create problems?
Is the replacement likely to corrode as well? Am I best getting the original replaced asap in the hope that the replacement will corrode while still undr warranty, or should I wait until just before 2 years is up before drawign their attention to it?
So many questions...
Same problem. Here in Quebec, if you live along the St-Laurent river, or if you ride in winter, you have this problem. It is due to the salt on the road, or carried in the air. The paint BMW uses is "Environmentaly" friendly, but no good.
Paul Jr
1200gs oO
gavin@iow
Registered user
M8 X 20mm, see here - http://www.r1200gs.info/forum/showthread.php?t=246....so new bolts look the way to go...........
Still think dealers should change all these free of charge until BMW manage to sort this problem out.
Cheers
Steve
I got them, from here - http://www.stagonset.co.uk/fasteners?t=1171997829&page=stagonset_index.html&cart_id=1263248_12698
gavin@iow
Registered user
Micro-encapsulation is a form of thread locking, if you clean the thread with a tap, use a small amount of loctite.
Horsedribble
Registered user
The Galvanic Corrosion between dissimilar metals mentioned earlier is your culprit. Forgive me if I'm repeating anyone else's advice because I haven't read every post.
When placed in an electrolyte (salty water is perfect), different metals/alloys assume different corrosion potentials. It is this potential difference that is the driving force for galvanic current flow. The less noble material in the galvanic couple will become the anode and tend to undergo accelerated corrosion, while the more noble material (acting as a cathode) will tend to experience reduced corrosion effects.
Don't call me Boff cos that's a cut-n-paste, but I've had quite a bit of experience with this on aircraft.
I don't expect stainless steel or even titanium bolts will stop this from happening because they're still a significantly different material to the casing, although the bolts themselves will fare beter.
I'm in two minds about recommending these (see later) but you could try using 7075 T6 Alloy bolts. They're popular with the Streetfighter / customised Suzuki Bandit clan because they come in a nice range of pretty colours. See here for example http://www.racebolts.com/store/Aluminum-7075-T6-Fasteners-C17.aspx
BEWARE: I think I'd seek their professional advice first! Alloy bolts can get very stuck if they corrode cos they'll weld themselves in and that could be an expensive problem. They still need to be wet assembled with a corrosion resistant anti sieze grease (definitely NOT Coppercrest!) but they should dramatically decrease the chances of galvanic corrosion.
Ultimately it's a very hostile enviroment for the boxer front casing, lovely and warm whilst being blasted with wet salt. It doesn't get much worse than that!
When placed in an electrolyte (salty water is perfect), different metals/alloys assume different corrosion potentials. It is this potential difference that is the driving force for galvanic current flow. The less noble material in the galvanic couple will become the anode and tend to undergo accelerated corrosion, while the more noble material (acting as a cathode) will tend to experience reduced corrosion effects.
Don't call me Boff cos that's a cut-n-paste, but I've had quite a bit of experience with this on aircraft.
I don't expect stainless steel or even titanium bolts will stop this from happening because they're still a significantly different material to the casing, although the bolts themselves will fare beter.
I'm in two minds about recommending these (see later) but you could try using 7075 T6 Alloy bolts. They're popular with the Streetfighter / customised Suzuki Bandit clan because they come in a nice range of pretty colours. See here for example http://www.racebolts.com/store/Aluminum-7075-T6-Fasteners-C17.aspx
BEWARE: I think I'd seek their professional advice first! Alloy bolts can get very stuck if they corrode cos they'll weld themselves in and that could be an expensive problem. They still need to be wet assembled with a corrosion resistant anti sieze grease (definitely NOT Coppercrest!) but they should dramatically decrease the chances of galvanic corrosion.
Ultimately it's a very hostile enviroment for the boxer front casing, lovely and warm whilst being blasted with wet salt. It doesn't get much worse than that!
Gros Buck
Guest
You bet there's an issue. Strangely, most stainless steel are not recommended when chlorine is present. You have to select a stainless steel for that purpose. Also, the lower PSI affects both tensile and sheer. I am not sure about the SS alternative. Cadmium plated high tensile steel both is a better alternative.
gavin@iow
Registered user
Do a search on the internet for 'stainless steel disc bolts', and see if anyone is selling them? Massive tensile strength isn't necessary for disc bolts as they are in 'shear', i'd be more worried about the 'tensile strength' of the alloy threads in the wheel.
galvanic corrosion?
you don't think it's got anything to do with a raw edge on the paint where it's been machined off at the mating surface then?
this raw edge is also in direct line of fire from salty road spray.
you don't think it's got anything to do with a raw edge on the paint where it's been machined off at the mating surface then?
this raw edge is also in direct line of fire from salty road spray.
Gros Buck
Guest
I simply said I'm not sure on the SS bolt option. There are numerous documented event of stainless steel failure in presence of chlorine (like salt). (Namely in reservoirs) I do not pretend i'm an expert. I just raise a concern.
Paul Jr
gavin@iow
Registered user
Point taken, Paul, i'm no expert either. I'll certainly keep checking the disc bolts periodically.
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