BMW R75/5 rear hub spline repair (part 1) скачать в хорошем качестве

BMW R75/5 rear hub spline repair (part 1)

How to repair the Spline Cup (Driving Dog) on the rear hub of a BMW R75/5. The Driving Dog is easily replaceable using specialty fasteners and common household tools. This video (part 1) will show you how to remove your old worn driving dog by drilling out the factory rivets that hold the driving dog to the aluminum hub. The process is easy and you will need the following tools: 1. Center Punch 2. Hammer (or Rubber Mallet) 3. 1/8" drill bit 4. 3/16" drill bit 5. 3/8" Masonry drill bit 6. Level 7. Hand Drill 8. bench grinder, grinding wheel for a drill, etc. (optional) The instructions I followed for drilling out the old driving dog can be found on this gentleman's (Snowbum's - lots of great information on his site) web site. About halfway down the page is the relevant section. http://bmwmotorcycletech.info/rearwhl... I will summerize below: Drilling out the old Spline Cup (Driving Dog) 1) Start from the driving dog side of the rear hub. 2) Level the rear wheel using a level. 3) Using a punch, make a dimple in the center top of each rivet. 4) Using a high quality 1/8" drill bit, drill as straight as possible down into the center of each rivet 1/2". Use cutting oil (30 weight) to keep your drill bit from getting to hot and going dull. 5) Use a 3/16" drill bit, drill down into your pilot hole to enlarge the hole and further weaken the rivet. 6) Using a 3/8" carbide drill bit, drill off the top of the rivet. The carbide bit will quickly take off the top of the rivet and will hit the driving dog. No problem, this driving dog will be thrown away. 7) You should now be able to punch the rivets out of the rear hub. If the rivets are very tight and refuse to move, try some penetrating oil to help them break loose. If necessary, you could heat the hub slightly with a hair dryer to help expand the aluminum enough to punch out the rivets easily. 8) Using a 1/4" drill bit, drill out the rivet holes. Use a level to level out the hub and drill the 1/4" holes through the aluminum hub as straight as possible with a hand drill. Use cutting oil. Now that the old driving dog is off, you will need to replace it with a new one. The instructions on the website I linked to above discuss using aircraft bolts to bolt a new driving dog to the hub. These instructions appear to be for the R75/6 and /7 models and I found this to not work for my 1971 R75/5 rear hub. The bolts would not fit and did not leave enough clearance for the final drive. The /5 uses 5mm rivet holes, the /6 and /7 use 6mm rivet holes (6mm is very close to 1/4"). The method I used is to drill out the rivet holes in the hub and in the new /5 driving dog to 1/4" and use specialty aircraft fasteners (Hi-Lok) to bolt a new /5 driving dog to the rear hub. Drilling out the rivets holes in the hub and driving dog to 1/4" 1. Level the rear hub on a table (as level as you can get it). 2. Using a 1/4" drill bit in a hand drill, drill out the 5mm rivets holes to 1/4". Drill as straight as possible (using a hand drill with a bubble level helps). Use cutting oil (30 weight, etc). 3. You will not be able to drill a 1/4" hole in the /5 driving dog easily. The driving dog is hardened steel and cannot be drilled with anything but a carbide tipped drill bit. However, carbide tipped bits are cheap and available at any hardware store (masonry drill bits). However, a 1/4" masonry drill bit will not drill an accurate 1/4" hole in the steel driving dog. You will need to grind down the sides of the carbide tip on the bit to the exact diameter of your fastener (bolt). If you have a caliper, use it to measure the exact diameter of your bolt and attempt to grind down the masonry carbide bit to the exact same diameter. No need to be perfect, but get as close as you can and make sure to grind down both sides of the carbide masonry bit as evenly as possible. 4. Using the modified masonry bit, drill out the holes in a new /5 driving dog to 1/4". Note: It may be possible to purchase a /6 or /7 driving dog and fasten it to the /5 rear hub. If so, this may be easier than drilling out a /5 driving dog to 1/4". The /6 and /7 driving dog already has 6mm bolt holes. In Part 2 I will show how to easily fasten the new /5 driving dog to the rear hub using Hi-Lok fasteners.