Rear brake, hub and swingarm very hot

[roadrash]

Hello again, follow up to my post here.
https://ducatiforum.com/t/v4-brake-burning.62877/
Rear brake was very hot and had a bit of a burning smell. Rebuilt the caliper, replaced the master cylinder and the freeplay is good. Yet the disc, and caliper are very hot as is the master cylinder. Burn your hand after a few seconds hot. I checked the hub and swingarm and both are hot as well.

Can someone with a v4 ride their bike and report back on how everything in the back feels after a 15 ish minute ride? I need a sanity check. I can't think about what else could be causing the issue unless it's something with the hub or just heat from the engine radiating down the swingarm. On a stand at least the rear wheel rotates freely and i dont feel any slop. Owned bikes for many year and I know the v4 is a hot bike but I feel like everything in the rear should be somewhat cooler. When I get home I'll take a mirror and see if the pads are still touching the disk when hot.

 

[andyb]

check the free play on your brake lever..........

 

[SirJAG]

Yep. Brake might be slightly engaged. Is a real pain to get right especially if aftermarket rear sets.

 

[roadrash]

check the free play on your brake lever..........

Yep. Brake might be slightly engaged. Is a real pain to get right especially if aftermarket rear sets.

Well not to sound stuck up but if you read my post I state that the free play is good. Rear sets are stock

 

[andyb]

well not to say too stuck up too...you also said YOU rebuilt the calliper and the master cylinder...... my money is on operator error.

 

[andyb]

take away the lever actuator rod then and or the pedal so there is no load on the master cylinder what happens then?

still hot?

take away the hydraulic line to the rear calliper what happens then?

still hot?

take away the calliper then.

is the disc hot?

replace with another calliper as they are cheap as chips

sorted? connect pipe and bleed it.

hot again.

replace the master cylinder.

finally make sure you have correct adjustment on the lever.

 

[SirJAG]

Well not to sound stuck up but if you read my post I state that the free play is good. Rear sets are stock

No worries mate.

 

[airjawed]

Heat will cause the brake fluid to expand. If there is too little free play at the foot lever the pads will start to engage. I had this issue on my MV Agusta F3 800. Rode 10 minutes and the rear started to drag. Backed it out and all was fixed

 

[roadrash]

well not to say too stuck up too...you also said YOU rebuilt the calliper and the master cylinder...... my money is on operator error.

take away the lever actuator rod then and or the pedal so there is no load on the master cylinder what happens then?

still hot?

take away the hydraulic line to the rear calliper what happens then?

still hot?

take away the calliper then.

is the disc hot?

replace with another calliper as they are cheap as chips

sorted? connect pipe and bleed it.

hot again.

replace the master cylinder.

finally make sure you have correct adjustment on the lever.

I pushed my pads all the way in and rode 15 minutes to the store. Everything is still burning hot. Swingarm, hub are both hot but not as hot as the caliper or disk. The Mc is mounted right next to the exhaust but that seeps like a lot of heat to radiate down the line. As you can see in the picture I took immediately after checking the heat the pads are still not making contact. That's why I would like someone with a v4 to confirm hot hot theirs get.

 

[Deleted member 14059]

How many miles are on the bike? You may consider taking the wheel off, taking the sprocket assembly off, removing the eccentric and checking the bearings and re-greasing everything. I would think the steel parts would retain heat longer than the aluminum, which could explain when the caliper and rotor are hotter. Are you just touching them or using an IR thermometer?

 

[roadrash]

How many miles are on the bike? You may consider taking the wheel off, taking the sprocket assembly off, removing the eccentric and checking the bearings and re-greasing everything. I would think the steel parts would retain heat longer than the aluminum, which could explain when the caliper and rotor are hotter. Are you just touching them or using an IR thermometer?

Thought about picking up an ir but for now I've just done a touch test. That sounds like a reasonable hypothesis. I've never taken apart a single sided ducati hub but it can't be that hard.

 

[Deleted member 14059]

It's super simple.

Don't use a breaker bar. You need a 1/2" drive impact. I bought a Harbor Freight plug in for $40 bucks years ago that has slayed every thing I've tasked it with. You may have to keep the trigger depressed to give it the beans for a hot second, but I haven't been disappointed.

 

[roadrash]

It's super simple.

Don't use a breaker bar. You need a 1/2" drive impact. I bought a Harbor Freight plug in for $40 bucks years ago that has slayed every thing I've tasked it with. You may have to keep the trigger depressed to give it the beans for a hot second, but I haven't been disappointed.

I've done the wheel before.
So large star nut on both side then the 2 pinch bolts? Maybe a C-Clip?
How do you support the bike? Jack stands under the peg mounts?

 

[andyb]

Well I’ve got a v4 and I’ve had another v4 too. I’ve also had SSSA ducatis for the last 25 years and fundamentally the set up is the same of which the v4 shares several of the parts still.
So we need to define hot as of course there is a transfer of heat but nothing to shout about.
So as energy cannot be created or destroyed it has to be coming from somewhere… if it exists above the normal transfer.. and that area has to be the brake.

If it isn’t the brake why did you rebuild the calliper and master cylinder?

 

[NYCV4S]

I just had my 2023 Pani V4S have the rear hub bearings wear out within 1000 miles. I’d bet that’s your issue . My brake pads were visibly worn throwing major dust over the wheel and overheating without the use of the rear brake.

The caliper hanger also showed signs of heat and dust that wasn’t normal for 1000 miles.

I would have never known this was an issue if I didn’t get a set of aftermarket wheels and rear rotor to install , during the install the tech mentioned the sprocket side nut was able to be removed by hand and he could not remove the driveline axle as the bearings failed and caused the axle to become lodged in the hub . Upon removal , visible signs of the axle moving in ways it shouldn’t have , causing scarring to the metals and roller bearings and ball bearings both destroyed.

something wasn’t torqued to spec (ether too tight or too loose , and the entire hub and axle had to be replaced.

I hope this isn’t your case but it’s very likely.

 

[Deleted member 14059]

I've done the wheel before.
So large star nut on both side then the 2 pinch bolts? Maybe a C-Clip?
How do you support the bike? Jack stands under the peg mounts?

Jack stands can work if you have fixed pegs. There's a grub screw within the pivots of the Rizoma rearsets you can remove and thread into the threaded hole near the pivot point to turn the normally folding pegs into fixed ones. Or if you have the stock exhaust you can support it with a floor jack and some wood. If it seems a little precarious, have someone hold the handlebars if you need to wrestle the hub out. If you have exposed rafters in your garage you can also use straps to hold the rear up. If you have an Akrapovic exhaust, you can remove the cans and support the bike from the plate the rear suspension linkage is attached to. I've done this when changing the rear spring.

Two pinch bolts along with the clips that hold the large nuts on.

 

[JohnSmith]

Why do you have a V2 wheel on your V4?

 

[roadrash]

Well I’ve got a v4 and I’ve had another v4 too. I’ve also had SSSA ducatis for the last 25 years and fundamentally the set up is the same of which the v4 shares several of the parts still.
So we need to define hot as of course there is a transfer of heat but nothing to shout about.
So as energy cannot be created or destroyed it has to be coming from somewhere… if it exists above the normal transfer.. and that area has to be the brake.

If it isn’t the brake why did you rebuild the calliper and master cylinder?

When I bought the bike the rear brake felt no existsant so I bleed it. Then afterwards I could smell burning brake pads. I could also see glazing on the disk. I think my brakes my have actually been sticking. So I did a bunch of stuff. They feel better now. And I'm not really smelling burning pads but everything seems too hot. Which is why I'm not thinking something with the hub could be wrong. I know the heat has to go somewhere but it seems like way too much. I don't think the rear disk should be as hot as the frame when I'm not even using the brake.

I just had my 2023 Pani V4S have the rear hub bearings wear out within 1000 miles. I’d bet that’s your issue . My brake pads were visibly worn throwing major dust over the wheel and overheating without the use of the rear brake.

The caliper hanger also showed signs of heat and dust that wasn’t normal for 1000 miles.

I would have never known this was an issue if I didn’t get a set of aftermarket wheels and rear rotor to install , during the install the tech mentioned the sprocket side nut was able to be removed by hand and he could not remove the driveline axle as the bearings failed and caused the axle to become lodged in the hub . Upon removal , visible signs of the axle moving in ways it shouldn’t have , causing scarring to the metals and roller bearings and ball bearings both destroyed.

something wasn’t torqued to spec (ether too tight or too loose , and the entire hub and axle had to be replaced.

I hope this isn’t your case but it’s very likely.

Oof good to know. I'm right at 8000 miles. Everything looks good from the outside and the wheel spins freely. But that could be deceiving. I should definitely check.

Why do you have a V2 wheel on your V4?

Pretty sure that's a v4 wheel. It matches all the pictures.

 

[airjawed]

Hubs do make heat. It is packed with some grease which gets it hotter than you might expect. It doesn't take much to make it too hot to touch. Skin is sensitive. Get an IR gun. Cheap and you aren't dealing with a variable in skin sensitivity. Obviously make sure nothing is making contact where it shouldn't. I'll try to find exact numbers. And consider that ambient temps have a big influence as well.

 

[airjawed]

Found a post I made previously that might give some insight. MV Agusta F3 800....

I have serviced my rear hub and it does feel hot when I am riding hard/fast. On a 95F day riding between 70 - 120 mph for an hour it will be too hot to keep my hand on the hub and axle. Not instant burning but too hot to continuously hold. I don't really have rough hands so I would guess it is around 120-140 degrees F maximum? I don't use the rear brake generally during a ride unless I'm in a wheelie mood.