bevel box bearing

[zdaveuk]

took bike for mot today and failed it on rear wheel bearing excessive play
i mean major play , when riding it there was no sign of this at at, oil seal was intact no oil leaking.

so removed final drive to discover bevel box pivot bearings had gone too, dont have the necessary tools to do the bearings myself so dropped unit off at local bike garage , will undate on what state the bearing was in when i find out myself .
the only sign apart from excessive play in rear wheel both top to bottom and side ways was when i drained oil it looked like metallic paint.

bike has only gone 42000 miles but it is used for 2 up and touring and carry alot of gear eg tent etc could this be the cause of it ???

 

[B4ndit]

bike has only gone 42000 miles but it is used for 2 up and touring and carry alot of gear eg tent etc could this be the cause of it ???

It would be good to see if there was a trait with rear wheel bearing failure. Some bikes have a failure and some don't. It would be good if owners with a failure were more elicit with there riding mode and techniques. As you say you carry a lot of weight on yours so that might be a contributing factor. Has anyone had a failure on a bike that has only been gently ridden?

I have just had mine replaced as the bike has 72K miles on it and I wanted peace of mind for a few years. There was no issue other than a slight weep from the input seal. Paralever bearings were also done earlier this year in a moment of panic when I found some slight movement.

 

[Pekkavee]

bike has only gone 42000 miles but it is used for 2 up and touring and carry alot of gear eg tent etc could this be the cause of it ???

Yes it could be the cause. LT bikes, which have the same final drive, eat those big bearings in the final drive in 35.000 miles. And they weight a lot more.

Pekka

 

[Madmountainman]

That begs the question... Is there a better after market bearing replacement available?

 

[ebbo]

That begs the question... Is there a better after market bearing replacement available?

Well, I did hear of a guy who put an angular contact bearing in the FD of his 1150GSA in place of the standard deep grove bearing. The bike was on a RTW trip and went on for many many miles quite happily after that, the links well worth a little read

 

[Paul G (BHT)]

took bike for mot today and failed it on rear wheel bearing excessive play
i mean major play , when riding it there was no sign of this at at, oil seal was intact no oil leaking.

I would be very surprised if it was the wheel bearing if you were loosing no oil.

.... so removed final drive to discover bevel box pivot bearings had gone....

Aha, that sounds more like it.

bike has only gone 42000 miles but it is used for 2 up and touring and carry alot of gear eg tent etc could this be the cause of it ???

At that mileage it won't do any harm changing the wheel and pivot bearings anyway

 

[MikeP]

There was a recent(ish) post about an alternative (supposedly stronger) bearing.

The "man who knows" and whose guidance I'd always seek over and above that of anyone else, said that it wasn't a good idea.

The bearings are cheap enough and easy to replace. As for failures, the ones that I've seen have always followed a discovery that the Paralever pivots were shot or badly adjusted.

The same bearing, in the same final drive housing is used in the old K-Series (Bricks) of the Paralever type and the same internals on the non-Paralever K-Series. These don't fail except with high mileage (as you might expect with age and wear).

I have a pet theory why the K-Series bikes don't fail as often or as soon: They are not subjected to lateral play when the Paralever pivots are worn or badly adjusted.

The reason is simple as far as the non-Paralever bikes are concerned: They don't have Paralever pivot pins. The weakness is absent:

On Paralever K-Series, the final drive is braced by the spring strut as it's mounted on the final drive housing:

Any play in the Paralever pivots is compensated for by the spring strut as well as the Paralever bar underneath. So it is braced above and below the universal joint.

Unlike the Paralever models that have the spring strut mounted either centrally on the swing-arm or halfway along it like the last K-Series 'Bricks' (including the K1200LT):

The above version places a lot of reliance upon the Paralever pivots being in good order. Just looking at the different arrangements makes it apparent that a lot of lateral forces are going to be applied to the pivot pins and if they allow the final drive to move, even a small amount, then the forces applied when the bike goes from one lean angle to the other creates a small amount of lash inside the final drive. This lash has to be arrested by the main bearing cage. It's not designed for such lateral loads and it fails.

Look after your Paralever pivots and you'll have fewer or no problems with the final drive bearing.

Well that's my theory anyway.

 

[pablo666]

I've just had my third FD bearing go in about 20K miles, so this is very interesting. Each failure has followed long distance with heavy loads on an R1150GS. I'm seriously thinking of getting rid of it.

 

[DrFarkoff]

Pablo Did whoever rebuilt the drive check it over thoroughly???

Did you check that the gear oil going back in was GL5 spec??

I have a drive here and the inner bearing had some flecks of bearing chrome in it causing the bearing rollers to jam occasionally and make the bearing spin on the shaft which then in turn wore the inner shim ring down from 2.5 mm to 2.0mm

Not A problem methinks so I put it in the parts cleaning tank to get it well cleaned out and whilst getting the grunge out of the crevices I spotted the alloy boss that the small bearing is mounted on also turns in the crown wheel part

So basically this drive is screwed despite the main components being okay the wear factor and looseness is always going to allow more play than there ever should be

 

[MikeP]

I've just had my third FD bearing go in about 20K miles, so this is very interesting. Each failure has followed long distance with heavy loads on an R1150GS. I'm seriously thinking of getting rid of it.

If you don't already do so, do what Steptoe does to his own and recommends: Take the pivot pins out annually, clean them, re-grease them and re-adjust them.

You don't really need many tools to do it and once you've done it once you'll see how simple it is to do.

Then see if your final drive bearing is still so prone to failure.

 

[Qmouse]

I've just had my third FD bearing go in about 20K miles, so this is very interesting. Each failure has followed long distance with heavy loads on an R1150GS. I'm seriously thinking of getting rid of it.

I was in exactly the same situation as you and had bearings checked and replaced by well respected members of this parish 3 times. The FD was crap and had always been so. I had to replace the FD with a S/H one. After that a vibration that had always been there dissapeared and I have had no further problems.

There are bad FD's out there and nothing you do will solve the problem. Replace it with a known good one.

Q

 

[Steptoe]

I spotted the alloy boss that the small bearing is mounted on also turns in the crown wheel part

That happens when the crown wheel unit is heated up in an oven. It fecks it up.
There is no need to heat up the crown wheel unit when removing/replacing the crown wheel bearing.

I'm not suggestiing that YOU heated up the crown wheel previously.

 

[DrFarkoff]

I am guessing also that there is no fix for it Neil?

Nope, as you say never heated that bit, just the inner cover to slip the big bearing / assembly into

Do you think that maybe the inner bearing spinning on the shaft would generate enough heat to break that "bond" between the boss and the crown gear

That happens when the crown wheel unit is heated up in an oven. It fecks it up.
There is no need to heat up the crown wheel unit when removing/replacing the crown wheel bearing.

I'm not suggesting that YOU heated up the crown wheel previously.

 

[pablo666]

Pablo Did whoever rebuilt the drive check it over thoroughly???

Did you check that the gear oil going back in was GL5 spec??

I have a drive here and the inner bearing had some flecks of bearing chrome in it causing the bearing rollers to jam occasionally and make the bearing spin on the shaft which then in turn wore the inner shim ring down from 2.5 mm to 2.0mm

Not A problem methinks so I put it in the parts cleaning tank to get it well cleaned out and whilst getting the grunge out of the crevices I spotted the alloy boss that the small bearing is mounted on also turns in the crown wheel part

So basically this drive is screwed despite the main components being okay the wear factor and looseness is always going to allow more play than there ever should be

Well I carefully did the job myself after reading up everything I could find on here and on Ad-rider site. I'm happy that it all looked good to me. The second bearing that went; I caught after finding filings in the FD oil. The balls of the bearing showed signs of metal slivers having sheared off the balls. Other than these 'chips' the bearing was fine. I assumed it was poor quality metal, and put in a new one from BMW. That one only lasted about 5K. This one, I'll be looking at this week, has lasted a bit longer, but still premature failure, with no play to be felt at the wheel. Symptoms were a wheel speed knock and dry rub sound that was intermittent. Last service was march, new oil, and no play. Trip to france (prob 1.5K miles) over 6 weeks fully loaded and bearing shagged.

 

[pablo666]

If you don't already do so, do what Steptoe does to his own and recommends: Take the pivot pins out annually, clean them, re-grease them and re-adjust them.

You don't really need many tools to do it and once you've done it once you'll see how simple it is to do.

Then see if your final drive bearing is still so prone to failure.

Thanks mike, I will be doing that this week, depending on the weather!

 

[DrFarkoff]

Away and look at your bottle of gear oil and check it (if you still have any left )

Doesn't matter what it is EP 80 Ep 90 Ep73w90 synth etc etc as long as it is GL5 specification if it's not GL5 then you may well have the explanation Rob farmer can explain it better than me

Also when you take it apart check for the wee taper bearing spinning on the shaft it should be a snug fit and while you are at it try to hold the crown wheel in one hand and spin the conical boss with the other

If they move then the clearances will all be out of kilter

Well I carefully did the job myself after reading up everything I could find on here and on Ad-rider site. I'm happy that it all looked good to me. The second bearing that went; I caught after finding filings in the FD oil. The balls of the bearing showed signs of metal slivers having sheared off the balls. Other than these 'chips' the bearing was fine. I assumed it was poor quality metal, and put in a new one from BMW. That one only lasted about 5K. This one, I'll be looking at this week, has lasted a bit longer, but still premature failure, with no play to be felt at the wheel. Symptoms were a wheel speed knock and dry rub sound that was intermittent. Last service was march, new oil, and no play. Trip to france (prob 1.5K miles) over 6 weeks fully loaded and bearing shagged.

 

[B4ndit]

MikeP. What you say does it for me.

Off to check my paralever bearings now.

 

[davegs]

MikeP. What you say does it for me.

Off to check my paralever bearings now.

Don't worry about it that's how we all learn!

 

[MattW]

My pet theory is that some FD's were poorly shimmed in the factory (same goes for gearboxes). So if you change a failed bearing on a 'bad' FD, using the original shim (as most of us will), then your new bearing will be subject to the same out of spec preload as the old one and is doomed to the same failure...

I'm not sure how feasible it is for a 'home mechanic' to check / measure the shimming on a final drive. I did once see a video made by an American showing a procedure of sorts but I don't know if it's any good.

 

[B4ndit]

For everyone's info. I recently had my FD bearing and input seal done at BMW for a shade over two hundred quid. Not much more than a chain and sprocket on many other bikes. And it now has a two year warranty on the work done.