Final drive unit

[gatesy]

2007 RT.

At the junction of the final drive unit main bearing and the axle dust cap I have slight bubbling of the finish to the casting. I know it's cosmetic but the rest of the bike is superb so is there a fix for this I wonder?

Tks

John

[guest2360]

If its still in warranty BMW will normally replace the corroded part.  If not it will need to be rubbed down and repainted. You will be lucky tom get the paint from BMW though.  Leave it and it will only get worse. 

[David.]

If you think that the "bubbling" is part of the casting process finish & the paintwork is intact, I would be tempted to leave it alone.

Should the appearance of the area deteriorate, then there may be some corrosion beneath the paintwork which would require attention.

Rubbing down the area and touching up with Silver Hammerite Smooth paint or Aerosol is one option.

For a professional "as new" look, the part could be sand blasted to remove the paint, rough casting areas made smooth, then powder coated or resprayed.

[THUMPER]

Don't ever use any Hammerite paint on anything you value except garden tools

The stuff contains Silicone and use what solvents you want, you'll have to vapour blast it before the new paint adhere to the metal properly

[Daniel66]

Thumper is right, especially if the intended fix involves powdercoating, anything that includes silicon will interfere with the final finish. With powdercoating, silicon causes 'starring' which appears as 'dimples' and an uneven finish. To remove any prior paint or powdercoat we used to ensure garnet blasting only was used.

[David.]

Unfortunately managed to spill a small amount of brake fluid on the FD unit, resulting in the paintwork beneath the rear brake calliper becoming damaged.

Had the FD unit re-sprayed in-situ, without any dismantling other than removing the calliper. The silver paint is probably a shade lighter with a slightly more lacquered finish than that of the original swinging arm. The work was completed by a local body shop, Vehicle Smart Middlesbrough, http://www.vehicle-smart.co.uk/. For the cost, I'm quite pleased with the final result.

[simbo]

I hope the paint was 'approved' paint? It could cause catastrophic failure otherwise ;-)

[Levisp]

Unfortunately managed to spill a small amount of brake fluid on the FD unit, resulting in the paintwork beneath the rear brake calliper becoming damaged.

Had the FD unit re-sprayed in-situ, without any dismantling other than removing the calliper. The silver paint is probably a shade lighter with a slightly more lacquered finish than that of the original swinging arm. The work was completed by a local body shop, Vehicle Smart Middlesbrough, http://www.vehicle-smart.co.uk/. For the cost, I'm quite pleased with the final result.

I had two Mini car wheels repaired and resprayed silver by a mobile wheel guy recently and they look like new. I asked the guy if it was possible to do the same to the engine or final drive on my bike if I needed it. Reply was no prob easy. Begs the question why BMW replaces these parts instead of getting them resprayed when there is a warranty claim over corrosion. Seems an expensive way to do business. If I ever have a problem I will do what you have done and get them resprayed. Probably end up with a better finish.

[David.]

I had two Mini car wheels repaired and resprayed silver by a mobile wheel guy recently and they look like new.

Likewise, a couple of years ago, I had two Suzuki car wheels repaired & re-sprayed by VSM, they too look like new. It's for this reason, I took the RT to VSM for the FD unit to be re-sprayed. The FD unit is alloy, silver & round like a wheel!

[BeeJay]

When I had the corrosion issues with my 2014 LC I asked at Chester Motorrad about getting the small areas of corrosion dealt with rather than BMW sending out the cases and me paying for the labour to change them. They said that BMW don't do thet and they didn't know of anyone who could. I was sorely tempted to get it sorted myself until they made me an offer I couldn't refuse on a new bike.
I'm sure that there are companies out there that would make a good job of repairing a bit of corrosion. Alloy wheels are being repaired all the time.
On the 2018 LC they have painted the engine and drive casings black. Wonder why?