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-   -   Seized rear F4 Hub- advice please (https://www.mvagusta.net/forum/20-maintenance-tech-issues-all-4-cyl-models/241345-seized-rear-f4-hub-advice-please.html)

Chilblane 03-11-2019 05:13 AM

Seized rear F4 Hub- advice please
 
After approx 1800 miles from new, the chain could do with slight adjustment. No matter what I do with the "C" hook tool with extension bar the serrated ring refuses to budge, and with the bolts removed. I don't really want to resort to a chisel and hammer for fear of damage, just wondering if anyone has tried a release agent. There used to be a something called "plus gas" available in the UK that was used to free up corroded threads etc, I don't if this would help, any ideas much appreciated.

theknurl 03-11-2019 06:50 AM

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Chilblane;
A 50/50 mixture of ATF (automatic transmission fluid) and acetone is the best penetrant ......
That said, put 2 putty knives in the slot in the swing arm, then a large screwdriver between them....
TAP VERY GENTLY ON THE SCREWDRIVER, DON'T HIT THE HUB!!!
YOU ONLY NEED TO EXPAND THE SWING ARM A FEW THOUSANDS OF AN INCH:wink2:

silentservice703 03-11-2019 07:00 AM

As Noel has eluded: use a very small wedge in the swingarm slot and protect the adjacent surfaces.

Chilblane 03-11-2019 11:12 AM

Quote:

Originally Posted by silentservice703 (Post 2563301)
As Noel has eluded: use a very small wedge in the swingarm slot and protect the adjacent surfaces.

Thank you SS703, and Noel

I forgot had some tree workers wedges in hard nylon, tried these with duck tape covered brass angle and still no luck, will try and soak it over night with Noel's liquor recipe.

mitchy 03-11-2019 04:33 PM

1 Attachment(s)
You really need to remove the hub and clean/lubricate the outer surface of the hub and the swingarm where the hub sits with anti-sieze.
I would also service the hub while it is out.Seems like you are dealing with a bit of corrosion there.
You don't want your hub to look like this-

Attachment 459473

theknurl 03-12-2019 12:53 AM

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Chilblane;
Not my recipe......it came from the guys on the North Sea oil platforms and was posted on the now defunct MVAgustaUK Forum

Mitch;
I still have that hub......that a mechanic would do that pisses me off......need to weld it up and refinish it

Chilblane 03-12-2019 06:04 AM

Quote:

Originally Posted by mitchy (Post 2563379)
You really need to remove the hub and clean/lubricate the outer surface of the hub and the swingarm where the hub sits with anti-sieze.
I would also service the hub while it is out.Seems like you are dealing with a bit of corrosion there.
You don't want your hub to look like this-

Attachment 459473

Mitchy, I have been reading your hub thread with great interest and alarm, as a fairly newcomer to MV I was not aware of the hub problem. If my hub is damaged at a total bike mileage of 1800 (dry miles) I think I will opt for one of yours instead of the OEM. Without going through the 75 pages of your hub article could you please advise where they can be sourced in the UK.
Thankyou

silentservice703 03-12-2019 07:21 AM

@Chilblane: Since your bike appears to be a 2016, the initial hub issues have been sorted out with a redesign. Not to queer a deal for Mitchy's excellent hub...which doe s work in your bike...but , rather to set your mind at ease.

The first gen hubs had major issues if people didn't maintain the hub.

mitchy 03-12-2019 04:02 PM

Quote:

Originally Posted by Chilblane (Post 2563463)
Mitchy, I have been reading your hub thread with great interest and alarm, as a fairly newcomer to MV I was not aware of the hub problem. If my hub is damaged at a total bike mileage of 1800 (dry miles) I think I will opt for one of yours instead of the OEM. Without going through the 75 pages of your hub article could you please advise where they can be sourced in the UK.
Thankyou


You can purchase my hubs in the UK from forum member "gotojoe" Joe has stock and lives in Ireland.:wink2:

Chilblane 03-12-2019 04:28 PM

Quote:

Originally Posted by mitchy (Post 2563557)
You can purchase my hubs in the UK from forum member "gotojoe" Joe has stock and lives in Ireland.:wink2:

Thank you, I will contact him. Apologies for the post in your hub section "sale enquiry" I did not notice the Design Corse company has an active thread on this site until 30 seconds after I sent you the enquiry

esq'z me 03-12-2019 06:40 PM

@Chilblane Your hub is not likely to have any problems unless it is neglected/abused, or you over-tighten the chain and/or swing arm pinch bolts.

If you inserted a wedge (with fully loosened pinch bolts) into the swing arm and expanded the pinch point just a tiny bit you should be able to get the hub to move. May need an extension on the tool kit spanner, and maybe smack that extension with a mallet.

But it will move. If it was seized solid you would also have massive corrosion in many other areas.

Deano 03-12-2019 09:09 PM

Quote:

Originally Posted by silentservice703 (Post 2563477)
@Chilblane: Since your bike appears to be a 2016, the initial hub issues have been sorted out with a redesign. Not to queer a deal for Mitchy's excellent hub...which doe s work in your bike...but , rather to set your mind at ease.

The first gen hubs had major issues if people didn't maintain the hub.

Not sorted just less likely to seize. If you do enough kms on the new gen hub the spacers wear and the hub nips up. MV don't do hubs or headlights. Original hub seizure at 5000k, second gen hub spacers rooted at 45000k. I bought a Mitchy hub to finally lay this problem to rest.

Cheers

Deano

Chilblane 03-13-2019 03:44 AM

Quote:

Originally Posted by esq'z me (Post 2563583)
@Chilblane Your hub is not likely to have any problems unless it is neglected/abused, or you over-tighten the chain and/or swing arm pinch bolts.

If you inserted a wedge (with fully loosened pinch bolts) into the swing arm and expanded the pinch point just a tiny bit you should be able to get the hub to move. May need an extension on the tool kit spanner, and maybe smack that extension with a mallet.

But it will move. If it was seized solid you would also have massive corrosion in many other areas.

Thank you, I have tried a 3 foot long tube over the extension bar, which has almost disfigured its shape (the C ring) and still no success. I have soaked it gain overnight so hope today will bring some success. I appreciate your thoughts and silentservice in trying to save me expense where it may not be necessary. I will let you know the outcome:wink2:

Deano 03-13-2019 04:24 AM

Never mind the tiny bit. Get a fox wedge (or two) and drive them in the slots where the hub bolts were removed. Once the wedges have opened the gap 20-30 thou there's nothing that can stop it coming out. Don't keep trying to turn it, that's just more damage and frustration. Take the sprocket, brake caliper, hub circlip off etc. and tap it out with a hardwood or brass drift. Then you can clean it all up properly and service the hub.

Cheers

Deano

Chilblane 03-13-2019 04:54 AM

Quote:

Originally Posted by Deano (Post 2563639)
Never mind the tiny bit. Get a fox wedge (or two) and drive them in the slots where the hub bolts were removed. Once the wedges have opened the gap 20-30 thou there's nothing that can stop it coming out. Don't keep trying to turn it, that's just more damage and frustration. Take the sprocket, brake caliper, hub circlip off etc. and tap it out with a hardwood or brass drift. Then you can clean it all up properly and service the hub.

Cheers

Deano

Hi Deano

Yes that was my next step... in the removal of sprocket, calliper etc. Just got to find a way of supporting the back end of the bike safely, I have previously supported the bikes front end off of my garage roof timbers with a block and tackle ropes etc. Just an inconvenient distraction to the real job at hand. Thank you for all your tips most appreciated:wink2:

Cheers

John

esq'z me 03-13-2019 09:42 AM

Straps from beams above works well for the rear as well.

Put the bike on the rear stand, attach your straps, remove the rear stand.

Chilblane 03-13-2019 09:56 AM

2 Attachment(s)
I have had some success this morning and managed to move the hub fractionally. I am now of the opinion that the hub is not seized by corrosion, as on very close inspection it looks to me as though it is not sitting square in the swingarm. Although difficult to photograph close up, the picture with swingarm slot was taken after setting the pinch bolts to 25Nm and is clearly uneven by 2mm from a feeler gauge placed perpendicular to each bolt. In addition the gap between the teeth on the hub varies axially by 2.5mm at positions between 10 to 3 o'clock on the hub, taken inside the teeth of hub to swingarm body. I recall the gap/slot was never that uneven before I attempted to adjust chain so effectively the hub must have been over torqued by at least 1 bolt and the gap was considerably smaller, than as adjusted today. Therefore is it likely to have damaged the hub anyway?

As a recent newcomer to MV is it possible to badly fit a hub out of square in the swingarm, in other words is there that much clearance? as yet I do not know what the fit should be like, sloppy, or in my mind like a piston in a cylinder would be preferable before tensioning.

In addition and another puzzle to me is as you notice the chain was dealer replaced when I purchased the bike, I find it hard to comprehend that the dealer managed to fit the chain without having the same problem with adjustment, if of course the problem was there at the time. Well the next step is to get the hub out and see whats what. Any comments greatly appreciated

Chilblane 03-13-2019 10:00 AM

Quote:

Originally Posted by esq'z me (Post 2563679)
Straps from beams above works well for the rear as well.

Put the bike on the rear stand, attach your straps, remove the rear stand.

Thank you, Yes my thoughts exactly, thats my job for this afternoon:wink2:

silentservice703 03-13-2019 10:03 AM

It is unlikely, due to construction characteristics, that the hub is cocked in the swingarm unless something is seriously wrong.

Now, as for your torquing process: Do torque in small steps following the 1-2-1 protocol?

esq'z me 03-13-2019 10:04 AM

Take the hub out. It is a machined cylinder in a machined bore (swing arm) and it should be impossible to have it anything but square. Regardless of your observation of the pinch area gap.

Take the pinch bolts out completely. Stick a wedge in (plastic or wood won't damage the swing arm) and spread that gap. Knock the hub out with a block of hard wood and a heavy hammer. (I had to do that the first time I serviced my rear hub)

It is not rocket science. Pretty basic stuff. The parts (other than the angular bearing) are pretty robust.

Chilblane 03-13-2019 10:11 AM

Quote:

Originally Posted by silentservice703 (Post 2563689)
It is unlikely, due to construction characteristics, that the hub is cocked in the swingarm unless something is seriously wrong.

Now, as for your torquing process: Do torque in small steps following the 1-2-1 protocol?

Hi, Yes should have added that, I wound the bolts in 1/4 turn at a time alternatively

Chilblane 03-13-2019 10:17 AM

Quote:

Originally Posted by esq'z me (Post 2563691)
Take the hub out. It is a machined cylinder in a machined bore (swing arm) and it should be impossible to have it anything but square. Regardless of your observation of the pinch area gap.

Take the pinch bolts out completely. Stick a wedge in (plastic or wood won't damage the swing arm) and spread that gap. Knock the hub out with a block of hard wood and a heavy hammer. (I had to do that the first time I serviced my rear hub)

It is not rocket science. Pretty basic stuff. The parts (other than the angular bearing) are pretty robust.

Hi Thank you, but of course the uneven gap surrounding the hub to swing arm makes it look as though it is not square. I don't know if the front face of the swing arm bore is out of square, are they cast?

esq'z me 03-13-2019 11:01 AM

The bore is machined....quit worrying about that...take the hub out and have a look.

Rear hub problems are NOT a rampant certain to fail thing. More people (who do proper maintenance) have never had a problem than people who have..... and in 2010 the factory made changes to address the weak area.

You have let a thread about hub failures create an unrealistic fear.

Granted, your inability to rotate the hub in the swing arm is not normal, but I will wager there is a very simple explanation that will be revealed once you pull the hub out.

Chilblane 03-13-2019 11:52 AM

2 Attachment(s)
Quote:

Originally Posted by esq'z me (Post 2563707)
The bore is machined....quit worrying about that...take the hub out and have a look.

Rear hub problems are NOT a rampant certain to fail thing. More people (who do proper maintenance) have never had a problem than people who have..... and in 2010 the factory made changes to address the weak area.

You have let a thread about hub failures create an unrealistic fear.

Granted, your inability to rotate the hub in the swing arm is not normal, but I will wager there is a very simple explanation that will be revealed once you pull the hub out.

Hi esq'z me,

Your quite right I am bit of a worry guts, like you getting on a bit and may not be around too long, so ride time is precious:smile2:

However I have delay for getting on with the hub for longer straps to arrive to lift her up, so I thought I would remove the front sprocket to alter the gearing I had planned to do late last year. Anyway removed the front sprocket OK and notice that there is uneven wear on each side and for only 1800 miles I thought that amount is quite excessive. Another indication that the drive is a little skewed maybe?

esq'z me 03-13-2019 04:58 PM

I think maybe someone has mis-assembled the hub on installation. That wear does indicate mis-alignment. What does the rear sprocket look like?

Chilblane 03-13-2019 05:19 PM

Quote:

Originally Posted by esq'z me (Post 2563743)
I think maybe someone has mis-assembled the hub on installation. That wear does indicate mis-alignment. What does the rear sprocket look like?

The right hand side seems worse, which fits with the front sprocket, and the out of square (if so) going off to the right

Chilblane 03-13-2019 05:48 PM

Just wondering if I should do nothing further and see if there is any possibility of MV honouring a warranty claim, the warranty expired last July.

silentservice703 03-13-2019 06:02 PM

Were it me, I would document with pictures and get the hub out to see the condition of the swingarm hub bore.

Chilblane 03-13-2019 06:18 PM

Quote:

Originally Posted by silentservice703 (Post 2563773)
Were it me, I would document with pictures and get the hub out to see the condition of the swingarm hub bore.

Yes I will do that anyway (document pictures) but in the worst case scenario a swing arm bored off 90 degrees, thats an expensive lump. I rather doubt that is the case as the hub definitely does not look straight or measure so relative to the swinging arm, so hopefully just a new hub and drive!

phunkinit 03-14-2019 09:12 PM

Reminds me of a Jap bike with same issue.

It al came down to incorrect placing of the ertalon chain slider/guide.
Same wear on the sprockets and abnormal tension on the rear wheel hub

The chain guide was pushing the chain to the right, while the alligning was fighting to get back to the left


Take good look at the chain slider, abnormal wear could point you in the right direction.

mitchy 03-14-2019 10:06 PM

Quote:

Originally Posted by Chilblane (Post 2563777)
Yes I will do that anyway (document pictures) but in the worst case scenario a swing arm bored off 90 degrees, thats an expensive lump. I rather doubt that is the case as the hub definitely does not look straight or measure so relative to the swinging arm, so hopefully just a new hub and drive!

Can you beg,steal or borrow a 1 metre long straight edge,then check the alignment yourself by sitting it against the rear sprocket,then along to the front sprocket.
I would doubt very much if the swing arm has been machined out of alignment.
Have you checked for any movement in the hub with the rear wheel on yet?
That is the first thing I would do.
Next check your sprocket carrier/cush drive rubbers and spacer for any wear.

theknurl 03-15-2019 04:00 AM

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My vote?
The POS 2nd Gen cush drive is wrong or there is an extra washer on top of the hat shaped spacer......
a that would give you the wear on the inside of the countershaft sprocket :wink2:

Chilblane 03-15-2019 05:45 AM

Quote:

Originally Posted by mitchy (Post 2563955)
Can you beg,steal or borrow a 1 metre long straight edge,then check the alignment yourself by sitting it against the rear sprocket,then along to the front sprocket.
I would doubt very much if the swing arm has been machined out of alignment.
Have you checked for any movement in the hub with the rear wheel on yet?
That is the first thing I would do.
Next check your sprocket carrier/cush drive rubbers and spacer for any wear.

As most members have said the hub is abnormally stiff and needs investigation so I will try and remove it over the weekend and verify the condition of the swing arm bore and hub surface.

There is no movement in the hub with the wheel in situ. I can carry out an alignment check as well, and inspect the Cush drive when I get the bike's rear end off the ground.

Chilblane 03-17-2019 08:24 AM

4 Attachment(s)
The hub was successfully extracted after the Cush drive removed. Now with better access the gap measured between the hub and face of the swing arm was at its worst 3mm varying axially as previously mentioned. Attached is an out of focus picture but you can just about see the gap. The hub surface condition is excellent. Swing arm bore surface generally the same save for some minor marks confined to approx 35mm long x 10mm wide at about 7 o'clock position (not easy to photo) Hub returned to swing arm after a couple of burrs were filed off the teeth, presumably caused by the force of the C wrench. Hub now hard up against the swing arm OK. Trial torque the hub bolts at 25Nm has now returned the slot in the swing arm to a parallel slot/gap. Finally pinch bolts then slackened and C wrench allows easy hub movement.

After cleaning up surfaces of the shaft and and hub there are signs of scorching on the sprocket side bearing. The sleeve of that bearing removed and its I/d varies by 0.08mm. Is that within tolerance?

The rear sprocket was cleaned up and the wear on the inner side is clearly variable, and is not flat when laid on a glass surface!

Chain alignment chain checks were not taken, as I think most would agree that the hub not sitting square in the swing arm bore is the cause of the problem.

If the tension bolts have been over torqued is it possible this could have damaged the hub body? I do not have a vernier large enough to check for any ovality.

If advice would be to replace bearings and seals in the existing hub, where are quality components available?

Of course the other question is how did the hub manage to be out of alignment in the bore of the swing arm (although now superfluous) interesting and maybe the distorted rear sprocket provides a clue?

Many thanks to everyone that helped me out of this jam (no pun intended):smile2:

silentservice703 03-17-2019 08:55 AM

Contact @theknurl for bearings and seals

Chilblane 03-17-2019 09:26 AM

Quote:

Originally Posted by silentservice703 (Post 2564337)
Contact @theknurl for bearings and seals

silentservice703

Thank you I will. Forgot to ask in my previous post is 0.08mm out of spec for a bearing of this type?

Chilblane 03-18-2019 04:28 AM

Quote:

Originally Posted by theknurl (Post 2563971)
My vote?
The POS 2nd Gen cush drive is wrong or there is an extra washer on top of the hat shaped spacer......
a that would give you the wear on the inside of the countershaft sprocket :wink2:

PM sent Sunday:smile2:

theknurl 03-18-2019 06:36 PM

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2 Attachment(s)
Chilblane;
Got your message......
Please post pictures of the inner races of the needle bearings
So far only one person has had a needle bearing failure......the inner seal was cut and all the grease went into the
center of the hub
Deburr the spacer that goes between the inner races of the needle bearings
It appears that there has been some water intrusion......was the sprocket nut tight?
If the 6810-2RS bearing is smooth when turned with your fingers use it again
DO NOT TORQUE THE PINCH BOLTS TO MORE THAN 15LBFT/20Nm

Here's what Factory torque numbers can do to a 1st Gen hub.....this is a double row bearing, only one row failed
the one inside the hub....the other one is inside the caliper bracket >:)

Chilblane 03-19-2019 07:02 AM

4 Attachment(s)
Quote:

Originally Posted by theknurl (Post 2564521)
Chilblane;
Got your message......
Please post pictures of the inner races of the needle bearings
So far only one person has had a needle bearing failure......the inner seal was cut and all the grease went into the
center of the hub
Deburr the spacer that goes between the inner races of the needle bearings
It appears that there has been some water intrusion......was the sprocket nut tight?
If the 6810-2RS bearing is smooth when turned with your fingers use it again
DO NOT TORQUE THE PINCH BOLTS TO MORE THAN 15LBFT/20Nm

Here's what Factory torque numbers can do to a 1st Gen hub.....this is a double row bearing, only one row failed
the one inside the hub....the other one is inside the caliper bracket >:)

theknurl,

Thank you, you have reminded me of what I forgot to mention at the weekend. The sprocket side nut was certainly not as tight as when I have slackened the wheel side (as a comparison) set at 200Nm by me, I have never slackened the sprocket side before.

Pictures attached of the inner races, confirm little or no burrs on the spacer. The 6810-RS is very smooth, and there is no grease leakage in the centre of the hub.

With the camera out have I taken a picture of the calliper support flange...is the position of the ABS/TC sensor correct? the manual shows it in a horizontal position but photo there does not have the same type of flange with a position option.

Many thanks for all your advice:smile2:

Chilblane 03-27-2019 07:37 PM

1 Attachment(s)
All back together now, I hope troublesome hubs will be a thing of the past!


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