Oil on the brake rotor

[nobleswood]

On my Griso the rear oil seal on the CARC blew which left a tell-tale pattern on the tyre and one side of the rear brake rotor.

I have cleaned off the oil with Dawn soap & water until the painted surfaces are squeeky. I have new sintered pads coming tomorrow from AF1 as the old ones were contaminated.

My question; should I sand the rotor with say 150 grit paper to ensure I have the oil removed & do I need to prepare or condition the surface for the rotor as I am using, I believe, a different brake pad material than the OEM Brembo pads ?

 

[Chuck]

So, I'm assuming you fixed the seal? Was it a bad bearing?

[nobleswood]

I was thinking of calling you, that idea of the apprentise only knowing so much...

I think it was self inflicted as I hadn't changed the oil in the 3 years I've owned the bike 

The seal blew but when I inspected the oil it wasn't very dirty, the magnetic tip on the lower plug had some filings but not more than powder. I pulled the seal & cleaned the bearing with q-tips to get an idea of the debris on each ball bearing , but there really wasn't much to write home about..

I talked it over with my mechanic, who I respect, who services my cars & Sprinter van & decided on replacing the $30 seal rather than have the bike out of commission and a $235 bearing replacement. I'm betting on being able to ride the bike through the summer & if the bearing does need to be replaced it will be a winter project.

[Chuck]

Failing memory says that the seal starts leaking when the bearing fails. Pete will be along shortly to refresh my memory.

[Lucky Phil]

7 minutes ago, nobleswood said:

On my Griso the rear oil seal on the CARC blew which left a tell-tale pattern on the tyre and one side of the rear brake rotor.

I have cleaned off the oil with Dawn soap & water until the painted surfaces are squeeky. I have new sintered pads coming tomorrow from AF1 as the old ones were contaminated.

My question; should I sand the rotor with say 150 grit paper to ensure I have the oil removed & do I need to prepare or condition the surface for the rotor as I am using, I believe, a different brake pad material than the OEM Brembo pads ?

 

The rear disk isn't very critical so I would just install the new pads and break them in per the manufacturers requirements and see how it performs. Not sure I'd do it any different for the fronts either. Pads work by depositing a microscopic layer of pad material on the disk but unless they are pulsing i'd just clean them with a solvent.The rider I crewed for in a WSB race years back wanted the disks rubbed with wet and dry before every session as he said it gave the brakes more initial bite. personally I couldn't see it but that's how you need to take care of the riders mentality as much as the bike. Amusing thing was though because he was a rider with a long term national profile the guys were were sharing a pit garage with were doing the same thing by race day:)

Ciao  

[Chuck]

Calling Mr. Roper. Mr. Roper to the courtesy phone, please..

[Lucky Phil]

7 minutes ago, nobleswood said:

I was thinking of calling you, that idea of the apprentise only knowing so much...

I think it was self inflicted as I hadn't changed the oil in the 3 years I've owned the bike 

The seal blew but when I inspected the oil it wasn't very dirty, the magnetic tip on the lower plug had some filings but not more than powder. I pulled the seal & cleaned the bearing with q-tips to get an idea of the debris on each ball bearing , but there really wasn't much to write home about..

I talked it over with my mechanic, who I respect, who services my cars & Sprinter van & decided on replacing the $30 seal rather than have the bike out of commission and a $235 bearing replacement. I'm betting on being able to ride the bike through the summer & if the bearing does need to be replaced it will be a winter project.

How many miles has it done?

Ciao

[nobleswood]

24,000 miles

what grit was the wet & dry ? 

[Lucky Phil]

18 minutes ago, nobleswood said:

24,000 miles

what grit was the wet & dry ? 

Ok, maybe just a seal issue then although I'd expect it to go for a lot more miles than that. Whenever I have a seal that fails I always look at the seal sealing lip and running surface with a mag glass for any signs of an issue. I had a friend years ago with a Hailwood Mille that had a dry clutch on his 3rd clutch seal replacement which I knew was wrong. When I looked at the primary gear seal running surface for the seal it had a spiral mark on it from the factory grinding process.

Chuck is also right of course and a failed bearing is also a possibility but once again pretty low miles. Pete will have a better idea of CARC issues.The only thing I know about the CARC is the ultra rare swingarm breakage and the pinion nut coming loose and those were from reading Petes posts. 

400 grit paper.

Ciao 

   

[nobleswood]

I carefully inspected the surfaces prior to installing the new SFK seal, but not to the degree of using a magnifiying lens.

I wasn't happy about tapping in the seal with a hammer & block so pressed it in using 2 x 4's & clamps to get it even & not wanting to damage the seal lip. However I am second guessing myself  if I used enough oil/ grease on the inner seal when It was installed.

[Lucky Phil]

16 minutes ago, nobleswood said:

I carefully inspected the surfaces prior to installing the new SFK seal, but not to the degree of using a magnifiying lens.

I wasn't happy about tapping in the seal with a hammer & block so pressed it in using 2 x 4's & clamps to get it even & not wanting to damage the seal lip. However I am second guessing myself  if I used enough oil/ grease on the inner seal when It was installed.

Seal instillation is more complicated than people think. I hate doing it and always have another one on hand just in case. Probably just me. Pressing in is the preferred option after getting the seal started initially but tapping with a protector/seal driver but sometimes you dont have a choice but to drive it in.

Directional mono seals are better than bi directional at keeping oil in and are generally used as OEM on seals where replacement is a lot of work. Thats why I always use OEM for seals that are work to get to like crank seals and gearbox input shaft seals.

Here's a new wrinkle. Some new material seals these days need to be installed dry and if you lube them they will leak. They work by depositing a layer of seal material on the running surface in the initial period of rotation. If the workshop manual doesnt say to lube the seal then install it dry. As if it wasn't complicated enough:)

On the subject of seals I've bought a LOT of Viton/FKM seals lately and I asked the seal guy how you tell the difference between a black Nitrile seal and a black Viton/FKM seal. He showed me that the Viton/FKM are more a charcoal colour and the Nitrile are closer to jet black. It's a subtle difference but if you look closely you can tell the difference. Important to know for fuel and + 100 deg C heat related applications.

Ciao

[nobleswood]

With so many variables  I'll just have to run it & see..

[Lucky Phil]

2 minutes ago, nobleswood said:

With so many variables  I'll just have to run it & see..

Yep, not trying to worry you, it should be fine.

Ciao 

[LowRyter]

I clean  my bikes' (not Guzzis) chains and wheels with WD40.  For sure I get some on the rotors.  I just just ride the brake a bit until it's all off.  Lots of heat on those rotors.

I just assume the seal is fixed.

[nobleswood]

I replaced the seal, just waiting on new brake pads to get on the road again & see if it all holds together

I'm qualified as a woodworker, still learning as a mechanic