Brakes not dis-engaging -- VERY hot!!!

[RobertB]

. If you see *any* signs of scoring (scratches) on the rollers, discoloration (bluing) of the metal on the rollers or races, or delamination (flaking) of the surface of the rollers or races, replace *all* the bearings and clean out the hubs and install new grease. .

Curious, how can bearings delaminate - the roller elements are homogenous. They start out as wire, are formed, heat treated, and ground. Bearings are not plated (at least I have never run across any) - the plating would never stand up to the pressure.

[Hamin' X]

If the rollers are subjected to unusual heat from friction, the surfaces can become hardened, similar to flame/induction hardening. this allows the surface to flake off. Fairly common failure mode.

~Rich

[kmclemore]

. If you see *any* signs of scoring (scratches) on the rollers, discoloration (bluing) of the metal on the rollers or races, or delamination (flaking) of the surface of the rollers or races, replace *all* the bearings and clean out the hubs and install new grease. .

Curious, how can bearings delaminate - the roller elements are homogenous. They start out as wire, are formed, heat treated, and ground. Bearings are not plated (at least I have never run across any) - the plating would never stand up to the pressure.

I used the word 'delaminate' because that's what it looks like, and effectively that's what it is - after work-hardening, bits of the top layer come adrift and flake off. I didn't figure most folks here would know what 'spalling' was. But since you asked, here's what it looks like...

"Spalling": Note the surface-hardened top layer has flaked away (delaminated), leaving pitting on the race surface. This is caused by 'surface fatigue' or 'work hardeining'. It is *very* common on wheel bearings in an early stage of failure, and in its earliest stages it can be seen as either tiny pits or small 'dents' in the bearing surface.



Think about it as the surface of the bearing getting massaged (compressed) under extreme pressure, over and over again, and much like when you bend a coat hanger back and forth it will lose its 'temper', get hardened and eventually simply crack. Similarly, the surface of a bearing cracks off once it gets work-hardened enough.

As it progresses it can get quite bad, ending in total disintegration of the bearing:



"Galling" is slightly different, and can also be sometimes seen on bearings when they are very near total failure. It is when material from one surface, through extreme heat and pressure, delaminates and attaches to the other surface. This is almost always accompanied by dis-coloring of the metal (usually a blue or straw color).

For those who are playing along at home, the final stage - when galling gets truly extreme - is "Seizure", where the parts get so hot that they literally weld themselves together. See the example, below, of a seized engine connecting rod bearing... this is sometimes (incorrectly) called a 'spun bearing'. Note the heat dis-colorization (blue and straw colors) on both the rod and the bearing material, and how the bearing has melted and been pressed out (called 'plastic flow').



You may now resume your regularly scheduled programming.

[kmclemore]

Since I couldn't post more than three photos, here's one of 'galling'... you can see where the material has changed color and where bits of the rollers have become welded and flattened to the race surface. There's also evidence of spalling, too, of course.



BTW, don't confuse spalling with corrosion damage, which is also understandably common on boat bearings. Corrosion damage is shown below... notice how regular the pattern is - it's where the rollers were sitting when the water entered the bearing. Do not be tempted to reuse corrosion-damaged bearings... they will very soon fail.

[RobertB]

I understand abrasion, pitting, galling, work hardening - just could not resolve delamination since it means different layers separating and bearing rollers/balls do not have different layers. None of the pictures resemble delamination - sorry, I go by the real meaning of the term. I also had a state inspector once tell me I needed new wheel bearing because the plating had come off - called the State Police on that one.

Back to the original question, I highly doubt any of this happened to bearings on Konig since it was for such a short period of time. If parts are available locally, if he actually had any experience and the proper tools to do the maintenance, and spending the money is not an issue, then changing all the parts is great - but he is traveling Friday and does not have experience doing this nor the time to sit down and figure it out. I really think he needs to concentrate on the source of the problem - the brakes. Either a master cylinder/solenoid or two separate calipers failing at the same time (when is the last time you saw brakes have the identical failure suddenly on different sides, not saying it cannot happen but not the usual way things happen). Fixing this in the time available is going to be challenge enough. The bearings are most likely going to only need repacking, seals nice but a grease gun on the trip can replace any grease lost. All of this is based on the fact that I do not know how long the trailer has been sitting - if it has been sitting neglected long term, I can understand the brakes corroding in place.

Lets wait and see what an examination Wednesday shows.

[seahouse]

Great pix, Kevin.

Some bearings are through-hardened, some are case hardened (carburized or carbo-nitrided, IIRC) or surface-hardened. I have no idea which are used in our trailers, but the bearings need not be work hardened to cause a lack of homogeneity in the metal – they come that way new from the factory.

The actual surface in the surface-hardened bearings (the thickness of which depends on the process, and how much is ground off) is much harder than the metal beneath it, which remains tougher. So there are clear distinct layers in the metal that are of different chemical compositions.

So some of the separation of the surface, that looks like ultra-thin metal foil that we are all describing, could quite properly be described as an actual de-lamination at this interface, even before the bearing surfaces (not just the races, but the balls/rollers too) have been re-defined by work-hardening.

Of course the “spun” bearing Kevin refers to it when the bearing itself completely seizes up, and instead the inner/outer races spin on their shaft/hub, destroying them, usually.

I’m also thinking shock cooling from water ingress causes some of the seeds for bearing failure (delamination) along the contact surface, especially where grease hasn’t been evenly spread. Or a single grain of sand in the wrong place. Or a microscopic crack in the hardened (but embrittled at the same time) surface.

- B.

[kmclemore]

I understand abrasion, pitting, galling, work hardening - just could not resolve delamination since it means different layers separating and bearing rollers/balls do not have different layers. None of the pictures resemble delamination - sorry, I go by the real meaning of the term.

With all respect, the 'delamination' answer was written for the OP, who, by admission, did not have detailed knowledge. I figure he was already overburdened with new knowledge - I didn't need to add 'spalling' to his load.

[c130king]

...I figure he was already overburdened with new knowledge...

"overburdened with new knowledge"...that sounds about right.

And "overburndened with fear"...that I will take these wheels off and get things so screwed up that I won't be able to get it working again.

I need a drink...it's after 6:00...in the morning...

[Catigale]

How about splooging? As in, the new wheel bearing grease splooged out of the wheel hub?

If your bearings spall in France, is it Gauling?

[Hardcrab]

Last summer I helped a fellow Mac'er at MDR with the same brake problem, except that it was discovered while the trailer was still unloaded.
A stock trailer, but the symptoms seem the same.

After three or four days in the water, he tried to reload the boat onto the trailer. Hooking up to the truck and driving to the ramp, the trailer wheels were locked and they just skidded along the asphalt. (Your loaded trailer could at least roll along.)

Thinking a hydralic issue, we opened the caliper bleed valves a crack expecting to see a squirt of fluid shoot out. No dice. Not a hydralic lock.

We locked out the surge brake just to see.
No dice.
At this point, very strange indeed.

He called Boat US to see about a tow/whatever, and he was advised to tap moderately heavy on the calipers and report the results.

The brakes retracted and away he was able to go.
Not sure of the longer term story, but it worked that day.

You have a different ending due to the 14 mile heat build-up, but changing the (melted?) rubber seals and repacking the bearings is called for.

The pucks can get stuck in the calipers.
A water/rusting issue?
A gremlin?

[raycarlson]

in france i beleive it would be Degauling, but if your truely interested in making your 1000 mile tow and sailing engagement,this is truely the time to break out the stashed boat bucks and get some professional help,because it surely sounds like you have no clue in hull what your looking at,and it's even worse to break down 500 miles from home and not know what your looking at. SPEND THE MONEY..

[RobertB]

He called Boat US to see about a tow/whatever, and he was advised to tap moderately heavy on the calipers and report the results.
The brakes retracted and away he was able to go.
Not sure of the longer term story, but it worked that day.
A gremlin?

I like the hammer idea but I generally reserve it for after I have exhausted other options (and patience) - that is why my wife always keeps me company when I need to change out headlight bulbs on her new VW Beetle - don't judge until you have experienced this result of german engineering humor.

One thing we did at the beginning of the season this year, after the trailer had sat over the winter with brakes rusting, was to use a small disc sander to clean up the brake disks before driving. My guess is that stainless steel disks are not stock.

[seahouse]

One thing we did at the beginning of the season this year, after the trailer had sat over the winter with brakes rusting, was to use a small disc sander to clean up the brake disks before driving. My guess is that stainless steel disks are not stock.

Hey Robert –

I think that’s a good piece of preventive maintenance. Like a pre-emptive strike before you have a problem!

I used to do the same thing once a year on my cars. Since I have the wheels off every 6 months or so during the switch from summer to winter wheels anyway, exposing the discs, I would roughen up the faces of the discs to slow the rate of glazing, as well as remove the ridge of rust that accumulates just outside the pad-swept surface of the disc.

What year is your trailer?- stainless discs were standard on my 2011. (and most motorcycles)

- B.

[Catigale]

Are the rotors on your trailer SS? My recollection is that even on SS brakes, the rotors were still cast iron for next essay heat dissipation.....

[seahouse]

I could be wrong about that - I won't see the trailer until the fall now to check (trailer in storage). Hmmm - they were pretty thin as I recall in my mind's eye - meaning stainless, but I dunno...

- B.