soft brake pedal- bad wheel bearing

[docc]

The rear brake pedal goes all the way down. A few full strokes and it's back solid. Fluid is full, no visible leaks, new pads and brake bleed less than a year ago (3,300 miles).

 

Any chance of bringing this back with a flush/bleed or am I in for a master cylinder rebuild?

 

Are there rebuild kits available for this Brembo?

 

TIA!! (Trying to get ready to ride the 500 mile round trip, backroads, to the Barber Vintage Festival in 10 days!)

[rossi46]

Docc I used this kit a while back

http://www.gutsibits.co.uk/pr/TheShop/index.php?f=e&Shnew=1&Model=1&ModelName=1100%20Sport,%20V11&Cat=BRA&CatName=Brakes&spPage=3

 

[czakky]

In my experience a bad master cyl. gives you good pressure that slowly drops out. Like brakes are there then at the same pressure you slowly lose the lever.

Sounds like a loose connection that let some air in, i.e. bleed nipple or banjo connection.

Had a similar issue on my clutch.

[luhbo]

Does this happen over night too, or only after some miles of driving? How long does it stay solid?

 

Hubert

[docc]

Right now, it feels solid as rock after sitting overnight. After rolling along a short distance, it goes away again.

 

Never had one do this before. I thought maybe a warped rotor is pushing the pistons back in to the calipers, but  I don't feel any pulsing in the lever.

[luhbo]

... I thought maybe a warped rotor is pushing the pistons back in to the calipers ....

 

I saw something similar years ago on a friend's Laverda with a selfmade break reaction rod/lever/whatever. The lever had play and hence wiggled the pads/pistons back into the caliper, quite the same as if the disc had been warped.

 

Hubert

[docc]

Thanks, Hubert! Indeed, the pistons were being pushed back into the calipers by wiggling at the wheel.

 

Here's why:

 

[docc]

Out pretty easy with a little heat (gun), resharpening the punch on the bench grinder a couple times and the judicious application of f=ma (500g Gedore machinist's hammer).

 

I can have a bearing tonight and back together again. The question is whether an O'Reilly "name brand" built in China is same/better/worse than the 7year old French bearing* that just failed. Other bearings I've found on the Guzzi are made in Turkey or Poland.

 

 

*(EDIT 10-17-2014; Just found in my records having replaced this bearing again after 35,000 miles - so: under warranty at ~14,000, another French bearing went 35,000, and again, now, after 40,000.)

[LowRyter]

holy moly  ...  glad you weren't buzzing around Telico Planes !

[docc]

Pretty amazing, though, to find this trouble yesterday, and have it fixed today.

 

The replacement bearing: Federal Mogul "National Bearings" 204-FF. (what, in the world, does that actually mean??)

 

Heat gun on the race, bearing in the freezer for 15 or 20 minutes, drifted right in. 

[luhbo]

don't think i'd be afraid of the china built bearing. kind of hard to avoid nowadays...

 

Exactly. The company behind it usually is one of the well knowns like FAG or INA anyway. Way more important is the right spacer length. You checked this probably, did you?

 

Hubert

[docc]

 

don't think i'd be afraid of the china built bearing. kind of hard to avoid nowadays...

 

Exactly. The company behind it usually is one of the well knowns like FAG or INA anyway. Way more important is the right spacer length. You checked this probably, did you?

 

Hubert

 

Oh, yes. Some years ago. The first bearing was replaced under 15,000 miles/24.000 km under warranty (although I installed it), second bearing (rear/left) went 40,000 miles, and the Sport just turned 92,000 mi/148.000 km while it was eating this bearing alive.

 

I remember some discussion about the meaning of the suffix on bearings, but don't recall the details. The French bearing MG supplied me was 6204-2SG1, and this one: 204-FF. While dimensionally the same, what is the difference?

[docc]

I'm pretty impressed it made it that far. I'm less impressed with myself that I didn't see it coming. 

 

In the past, I've made a habit of lifting the seal cover and adding a bit of high quality grease. I didn't do that with this replacement since I've bent and munted the seals sometimes before. Figured I'd leave well enough alone this time.

 

Still trying to learn that axiom, "If it ain't broke, don't fix it!" 

[chamberlin]

Docc, I am glad you found the problem to your brake issue, but sorely disappointed you bought a $7 bearing for your rear wheel! I ride about 1000 miles a year combined on all my bikes, so am I a sucker for buying $46 bearings? Maybe so! But you ride about 1000 miles a week on your V11.......a generic $7 alternator bearing?!?!?!?!

The silver goose deserves golden bearings! 

 

The OEM SKF is only $25 per bearing... http://www.mgcycle.com/index.php?main_page=product_info&products_id=1428  I know the rear wheel isn't seeing the same crazy axial and radial loading as the front wheel, but you already have seen what can happen when the bearing lets loose. I'd sure feel better about having a set of OEM bearings in there.

I suppose the new Chinese stuff is quite acceptable for most applications (i.e. alternators!)...but personally I would not want to guinea pig that test on my bike's wheels, as compared to respectable bearing mfgs from France, Germany, or Japan.

 

Sorry for the rant Docc!

 

Here are some fun links for bearing nomenclature:

http://www.gizmology.net/bearings.htm

http://www.microbluebearings.com/pages/BEARING-NUMBER-CODE-REFERENCE.html

http://www.engineerstudent.co.uk/bearing_numbers_explained.html

http://www.ahrinternational.com/NSK_nomenclature.shtml

[docc]

For sure, they had $7 Chinese bearings, but this was their "name brand" (Federal Mogul) product at $22.

 

I'll be keeping an eye on it. Impatience got the best of me and made me proud to have the bike back on the road in under 30 hours after the failure.

 

Once again, I feel lucky. Stupid, but lucky.