Trunnion Bearing replacement

[waveydavey68]

Folks,

I recently had my bike serviced and MOT'd at Chester Motorrad (local BMW dealer) with no issues other than an advisory regarding slight play with a "Trunnion" bearing which I need to monitor. They have quoted @£320 to replace.

What does this bearing do/ where is it? and is there anyone else who would be recommended to do the job at a more palatable price, or will I just need to pay the money?

Bike is a 2013 GS1200 LC
I'm between Crewe and Chester in Cheshire.

Cheers in advance

 

[walkingpictures]

https://www.ukgser.com/forums/showthread.php/383108-Rear-wheel-final-drive-bearing

 

[autogs]

https://www.ukgser.com/forums/showthread.php/383108-Rear-wheel-final-drive-bearing

Not the fd bearing, the trunion bearing

Sent from my SM-A202F using Tapatalk

 

[Boxflyer]

From Wiki
"Trunnion bearings:
In mechanical engineering, it is one part of a rotating joint where a shaft (the trunnion) is inserted into (and turns inside) a full or partial cylinder. Often used in opposing pairs, this joint allows tight tolerances and strength from a large surface contact area between the trunnion and the cylinder."

The most common location for this description of a bearing on our Paralever bikes is either where the front of the Paralever pivots in tapered roller bearings, or at the back end of the Paralever where the bearings are mounted in Final Drive and connect to the Paralever. These bearings are a straight/cylindrical roller bearing on the side where the wheel is attached and an Angular Ball bearing on the other side.
The front bearings have large threaded "bolt" type pivots that can be tightened to set/adjust for slack during installation. The rear pair, in the Final Drive, are more likely the site of this observed play you were advised to monitor. These back bearings are less robust, closer together handling the same loads, and are easily observed to be exposed to more water/dirt/contamination.

I replaced a complete Final Drive on my 08RT and found that the primary water barrier on the straight roller bearing side was only a "felt" material impregnated with grease.

Prices in the US for the straight roller bearing (33117684640) are about $17 and for the angular ball bearing (33117665037) about $63. It's not a difficult job if you have the tools and some mechanical background…but the price they want to charge is right in the range I would say is "reasonable" if it's going to be an issue for MOT in the future.

Good luck, just keep riding it until it doesn't pass MOT, then deal with it, would be my recommendation.
I have a 5th Final Drive elsewhere I'm working on as well…

 

[ShakeyGS]

Crispy fried trunnions

 

[beaver]

If it is the bearings on the arm, they are easy enough to do. I did mine on my twin cam. The bearings are not expensive either. Find the numbers and buy a quality one for Bearing services or somewhere.
Think I did all of mine for under £50....

 

[waveydavey68]

Cheers folks, appreciate the info

 

[the woodster]

Sounds like a winter project to me. Good luck.

 

[DrFarkoff]

What does this bearing do/ where is it? and is there anyone else who would be recommended to do the job at a more palatable price, or will I just need to pay the money?

Recommend that you get it checked by someone knowledgeable locally and It is just a smidgen ??

If it is just a smidgen? Let it be, I have a friend with an 1150 GSA with a smidgen of movement

He was panicking about it and I said why not just keep an eye on it and if it gets worse Or MOT aren't happy I will change it and shim it up for you

That was 10 years ago, it still has that "smidgen" of play

Sorry but a bit of knowledge of what it feels like is needed to "guess" at this one

Try it before you ride and when it is up to temperature say 50 miles

Easiest way is on centre stand and push down on top of the rear wheel and try and rock it in each way an "across" the frame direction A mm of movement is no biggie 3 plus would be concerning especially when hot

AS a bonus If I recall "correctly" the work carried out in BM workshop is subject to 2 years warranty

 

[Santa-2512]

Fcking hate trunnions with a passion

Many moons ago when i had not long passed my driving test, i had a old Triumph Herald

the first winter snow provided much amusement with a rear wheel drive car -

So much so that within a short space of time i was a rally god, Ari Vatanen move over, there way a new kid in town ...


Turning int o the road where i lived it hadn't been gritted or cleared, so i dumped the clutch and stomped on the accelerator

the back end stepped out and i steered into it..... right up the point where the front wheel on full opposite lock smacked the kerb and everything

stopped The wheel was now at 45 degrees the other way and the front end was awfully low ....

Bugger i'd snapped the LH trunnion on the bottom of the front strut ...

After a week or ringing round, i found a replacement in a breakers is Salisbury, so i borrowed a car and drove down there.

When i got the re the car was jammed against a wall, so i couldn't get to the LH trunnion only the RHS -

But being a spanner wielding god , i whipped it off and returned home triumphant in my awesomeness


Only to find there fecking handed, and a RH trunnion wont fit where the LH trunnion goes

£36 for a new one - almost 2 weeks wages fecking expensive month that was

 

[waveydavey68]

Good plan, seems like a sensible first option ��

 

[waveydavey68]

Cheers

 

[waveydavey68]

Recommend that you get it checked by someone knowledgeable locally and It is just a smidgen ??

If it is just a smidgen? Let it be, I have a friend with an 1150 GSA with a smidgen of movement

He was panicking about it and I said why not just keep an eye on it and if it gets worse Or MOT aren't happy I will change it and shim it up for you

That was 10 years ago, it still has that "smidgen" of play

Sorry but a bit of knowledge of what it feels like is needed to "guess" at this one

Try it before you ride and when it is up to temperature say 50 miles

Easiest way is on centre stand and push down on top of the rear wheel and try and rock it in each way an "across" the frame direction A mm of movement is no biggie 3 plus would be concerning especially when hot

AS a bonus If I recall "correctly" the work carried out in BM workshop is subject to 2 years warranty

Cheers