R80RT Final Drive Drain Plug

[Bikemike1]

Needed to change my oil(s). When It was time to drain oil from final oil, I discovered the drain plug was rather tight. I backed it off and after the oil had drained out, I gingerly screw drain plug back in but found it could not be tighten?? Further investigation, the drain plug had been striped and evidence of metal (aluminum) shavings were found in the threads??. Hmm, Ok, I have several options. What would you do? Would you get it re-treaded...gasket tape around treads and screw back in....?

Thank You

 

[arhd63]

Final Drive Plug

Needed to change my oil(s). When It was time to drain oil from final oil, I discovered the drain plug was rather tight. I backed it off and after the oil had drained out, I gingerly screw drain plug back in but found it could not be tighten?? Further investigation, the drain plug had been striped and evidence of metal (aluminum) shavings were found in the threads??. Hmm, Ok, I have several options. What would you do? Would you get it re-treaded...gasket tape around treads and screw back in....?

Thank You

I had same issue. Took swing arm off bike and had dealer re-tread stripped plug.

 

[dennisdarrow]

Till you get around to doing something permanent, like a heli-coil, and others, the big box stores sell rubber plugs that fit in nicely and hold there until you take them out...........Autozone and those other folks have various options and are worth the try........God bless.....Dennis

 

[James.A]

You could try to find a replacement plug with over-sized threads. I had good success with a piggy-pack oversized drain plug on a /5 transmission with stripped threads on the drain hole.

Another option would be a heli-coil in the drain hole.

 

[Bikemike1]

Thanks. I will try one of those ideas. Yes, still can not figure out why DRIVE SHAFT DRAIN PLUG was stripped. I replaced oil last year and was ever-so cautious. Again thanks.

 

[Bikemike1]

NOW I AM UPSET! I JUST COMPLETED MY LAST TREAD IN REFERENCE TO THE drive shaft drain plug being stripped, I immediately went to garage, loosen the level/filler plug for the final drive oil, it was torqued last year LESS than a couple of ft/lbs FROM THE required spec. to BE EXTRA SAFE, unscrewed it very cautiously, screwed it back in slowly with fingers and that too was stripped?? Last year both my drain plugs were taken off and put back in place with no problems. Both came off well today. But when I put them back on - stripped! Are these threads that sensitive? I am also certain and approached with caution. Unless owner before me had tighten them too tight and last year my oil change was the final draw. Any others had any problems with these items?

 

[pranda]

I would suspect the torque wrench that was used last .

 

[Bikemike1]

Possibility? I again, moments ago I attempted to screw in drain lever/filter and a no-go. I unscrewed drain plug, checked threads by flashlight and NOW there are no threads. As if they deteriorated. I carefully took a tooth pick and retrieve the stripped shavings. Not a good day. But I am still breathing and got my health. And not a major problem, just more work, money, time, and not able to ride until I can get issue resolved. Later

HAPPY EASTER ALL!!!

 

[lkchris]

On the later bikes of course never-ever remove the rear drive level check plug.

Just drain and measure the amount you put in according to specifications.

 

[lmo1131]

I've run my '73 /5 five since it came out of the crate and never stripped any drain plug. Exhaust spigot, that's another story, for later.

You didn't mention the "year" of your RT. But in either case, it would be much simpler to remove the final drive from the swing arm. Remove the rear axle, remove wheel, disconnect the brake rod, four nuts and it's off. New gasket for re-stall. Install the axle before completely tightening the four nuts on the swing-arm/final drive joint; it will ensure that final drive/swing-arm alignment is set. Then tighten the four nuts. But with your double-trouble I'd say it's time to have it "done right". Personally, with partial tear-down required, and my patience-index being at an all-time low, I'd ship it off to Ted Porter (or other experienced, well-tooled mechanic of your choice).

And NO TORQUE WRENCH for filler plugs. Order new copper o-rings and hand-tighten sufficiently to squish (technical term) the o-ring. After the first run, if it weeps a few drops just tighten it a bit further.

A learn-ed reading from Snobum's website.

Leaky driveshaft drain plug:

Usually this is due to the threads being stripped from over-tightening. If the threads are not repaired at exactly 90°, the plug does not go in straight. You CAN NOT repair the drain plug threads properly with the drive on the bike, NOR without disassembling some of the nose area of the drive, due to an internal threaded ring, that you probably won't see any of from the assembled drive...but you WILL damage things if you just try to re-tap the hole, or, worse, drill and install a Helicoil. The proper fix is to remove the rear drive and disassemble at the nose, and install a Helicoil. You need two special tools mentioned considerable above, and heat, and a new seal. I use HYLOMAR on the threads of the threaded ring. Hylomar works well on threads. You do NOT need to do re-shimming.

Some folks will, temporarily, just seal the drain plug with some sort of sealant, as the driveshaft oil change period is not at all critical.

Some torque values to know about are the Shock Absorber at 37 Nm (27 ftlbs); the rear drive drain plug at 22 Nm (16 ftlbs); rear drive fill plug at 28 Nm (21 ftlbs); swing arm drain plug 15 Nm (11 ftlbs); swing arm fill plug 14 Nm (10 ftlbs).

NOTE!....I seldom use a torque wrench on the drain and fill and inspection plugs. This is particularly so on the driveshaft drain; and MOST particularly so on the later drives that have the oil level inspection plug at the rear of the drive....it is very easy to strip the threads, even if using a torque wrench. There is NO need for those to be overly tight. Please use the above noted torque values with some common sense. Again: Be careful about the oil inspection hole plug...that horizontal rear facing threaded plug and washer on the later rear drives.... it is easily stripped. USE fresh crush washers & be careful to not use much torque. I am not giving a value for torque on that one...do it GENTLY by FEEL. You don't have to use that plug, you can fill 350 cc by measuring. I do check at the hole.

 

[PGlaves]

Order new copper o-rings and hand-tighten sufficiently to squish (technical term) the o-ring. After the first run, if it weeps a few drops just tighten it a bit further.

Out of curiosity, where do you get the proper size copper crush washers? Since BMW went to aluminum crush washers in the early 1980s for most common drain or fill plugs that is what I have used. But I would like to know where I can get copper ones.

 

[Bikemike1]

It is a 1986 R80RT.

 

[James.A]

Paul, have a look at this web page.

http://www.aircraftspruce.com/catalog/eppages/an900.php

 

[donbmw]

Paul, have a look at this web page.

http://www.aircraftspruce.com/catalog/eppages/an900.php

Those will not work. The inside dimensions are to large to seal for metric size plug. How I know is I work on aircraft. Have tried them since BMW went to the aluminum washers. I would also like to find the original copper washer or something that would work.

Don

 

[PGlaves]

Paul, have a look at this web page.

http://www.aircraftspruce.com/catalog/eppages/an900.php

Thanks

 

[88bmwjeff]

On the later bikes of course never-ever remove the rear drive level check plug.

Just drain and measure the amount you put in according to specifications.

The rear level check bolt became tight about five years ago, and I refuse to remove it. I figure next time the final drive is apart for a rebuild, that will be the time to remove the bolt and see what's happened. And, that's going to be a long time.

With this bolt, I used to just snug them up.

 

[lmo1131]

Out of curiosity, where do you get the proper size copper crush washers?

Actually Paul I'm at the very bottom of an old stash of stuff I've had for years.

Here's a source for metric crush washers; they're not asbestos filled, so would not be suitable for the high temperature rating required by AN900 (MS35769) Mil Spec standards. But I'm sure they'll be suitable for more earthly pursuits, and they;re only $0.45 a piece. 2mm x 12mm I.D. x 16mm O.D. (which is 0,5mm larger that OEM).

Their 18mm x 24mm might be usable as a drain gasket. The OEM size is 18mm x 22mm, but as long as the inside fits closely I don't think that extra material hanging over the plug would be a problem.

They also show an 8mm x 12mm crush washer that might be suitable for front forks; the spec on the BMW OEM part is 8mm x 11mm but I don't recall how critical the extra 0,5mm (1mm total) outside diameter is inside the lower fork cap. Looks like we're SOL on the 45mm x 52mm gasket for the lower fork cap (Hucky still has them).

https://www.belmetric.com/gca12x16-copper-hollow-crush-gasket-p-554.html?cPath=11_94

They carry a load of other "mechanics" supplies as well.

 

[James.A]

Thanks Lew, I am going to save that link. The "aircraftspruce.com" was a site I found while bumping around on google one evening. I did buy some non-asbestos copper crush washers from a site called SG enterprises, but they were in Canada and I ended up waiting several weeks for the shipment. They had good stuff.

 

[Bikemike1]

If I disassemble the drive from the swing arm and if I need to disassemble the nose of the drive so I can properly have it drilled for a heilcoil or re-tread, is that a difficult task? I do have a service manual. Are there any tricks or events to look for? Or by taking the nut off will do it?