Wheel Separation

[mndriver]

GD&T tolerance stack would have been significant for that to happen.

@Injun

What is the life of service of that trailer? How old is it and how many miles had been on it? Was there recent work that had been done to the brakes. The only thing that makes sense here to me is a recent hub change me incorrect studs used.

 

[ironpony]

It appears to be a significant, and unusual event. Barring incorrect parts, my guess was those holes were bored just enough inside the outer tolerance limit to hold the studs in place. Add some wear, hot summer ambient temps, and a abnormal heat source {dragging brake shoe) - voila! You have enough to let all the studs go at once.

That's a tough scenario to produce a root cause without something really stupid going on... like a hub that has been manufactured at the edge of the tolerance stack. Stress failure, metal fatigue, etc, is something that happens to one part - not ten.

How about it @Injun - were the wrong parts used?

 

[Injun]

GD&T tolerance stack would have been significant for that to happen.

@Injun

What is the life of service of that trailer? How old is it and how many miles had been on it? Was there recent work that had been done to the brakes. The only thing that makes sense here to me is a recent hub change me incorrect studs used.

The hub had been replaced within the last couple of months. Mechanic said he had to pound the original studs out and pound in different ones because the original ones wouldn't work with the Budd rims. So the studs were not what came with the hub.

 

[Injun]

The trailer is a 1995.

 

[Duck]

I take it these ain't like car and pickup studs where you just tap em in a little bit from the back side then mount the wheel and crank the hell outta the lug nuts with a 4-way?

 

[r3gulator3]

The hub had been replaced within the last couple of months. Mechanic said he had to pound the original studs out and pound in different ones because the original ones wouldn't work with the Budd rims. So the studs were not what came with the hub.

Wait, he pounded out studs (if they wouldn’t work with buds that means they were pilot hubs) to put in a different style? There’s your problem. Budd and piloted hub parts are not interchangeable.

 

[Hammer166]

Wait, he pounded out studs (if they wouldn’t work with buds that means they were pilot hubs) to put in a different style? There’s your problem. Budd and piloted hub parts are not interchangeable.

I'm starting to think this took a bit of unique engineering effort to even put this together!

 

[r3gulator3]

I'm starting to think this took a bit of unique engineering effort to even put this together!

That’s for sure. When I managed the school bus fleet, we had half and half budd/pilot and we even had a few Dayton set ups. All 3 require a different hub. I had gotten Misboxed parts before, there are things that go wrong especially if a tech doesn’t know what they are looking for. Typically a budd hub isn’t going to come with studs in it because usually a budd hub has inboard drums or the drum is behind the hub. Where as a piloted hub will have studs as everything is outboard.

With antique equipment like that if the tech was young, he probably assumed and didn’t do any research and slammed it together the way he thought it would work. And bosses are guilty of the “it’s gotta go get it done” mentality. Things happen. I’m just glad no one got hurt in this scenario.

 

[BrandonCDLtrucker]

This happened just yesterday on a brand new trailer I was parked behind at a service plaza. It was a hotshot flatbed trailer. One set of tires was coming off. The bearing looked shredded. What would cause this on a brand new trailer? The guy said he personally oversaw the greasing of the bearings. Could overtightening the bearings cause this?

 

[Hammer166]

This happened just yesterday on a brand new trailer I was parked behind at a service plaza. It was a hotshot flatbed trailer. One set of tires was coming off. The bearing looked shredded. What would cause this on a brand new trailer? The guy said he personally oversaw the greasing of the bearings. Could overtightening the bearings cause this?

Absolutely! Dry hubs used to be the number one cause of wheel end failure but I bet with the improved seals and greases we have nowadays that improper installation is now the most common cause

 

[r3gulator3]

The type of grease used can also be a factor. International had a recall on school bus and 37-3900 series chassis and the IC school bus line because the grease they used was too hard and caused bearing failure. Wheel bearings should get a Ronex MP high temp or the synthetic wheel bearing grease for heavy duty applications that I forget the name of.

 

[Injun]

I had to get all of Girlie's wheel bearings replaced. That was my ProStar. That goofy ratcheting keeper nut failed on all four drive axle ends. The teeth that were supposed to lock them broke. One of the spindles even had to be replaced because a bearing spun. I got rid of that stupid ratcheting crap and replaced them all with StemCos. The bearings looked like they'd been gouged, the races were trashed and I had shards of metal all throughout the axle ends from the disintegrating bearings. I'd never seen anything like that.

 

[ironpony]

Wait, he pounded out studs (if they wouldn’t work with buds that means they were pilot hubs) to put in a different style? There’s your problem. Budd and piloted hub parts are not interchangeable.

Well... there you go. Wrong parts, pounded in, and enough heat to expand the hub to the point that the studs couldn't maintain whatever fit was achieved.

@Injun - you should probably get your company to inspect all their trailers with this type of wheel assembly.

 

[Duck]

Is this a small fleet? How can a mechanic even remember a particular job if it's a big fleet with hundreds or thousands of identical trucks and trailers?

I can't even remember which of the two Goldwings I changed the oil in this spring so I just changed them both last week. And they're not even close to identical.

 

[r3gulator3]

Is this a small fleet? How can a mechanic even remember a particular job if it's a big fleet with hundreds or thousands of identical trucks and trailers?

I can't even remember which of the two Goldwings I changed the oil in this spring so I just changed them both last week. And they're not even close to identical.

You’d be surprised in what detail I can remember jobs I did on trucks.

 

[mndriver]

Proper records help with recalling what's done.

 

[ironpony]

Proper records help with recalling what's done.

In a "real shop," yes. In the @Duckdom, beer interferes with the prospect of any record keeping.

 

[Duck]

In a "real shop," yes. In the Duckdom, beer interferes with the prospect of any record keeping.

Yeah one time I got drunk and decided to make a deer bumper for one of my vehicles.

It looked really nice the next day when I was admiring my work. Everything was perfectly square and symmetrical and all of the welds were perfect with no incomplete spots where water could get in.

Only thing I couldn't figure out was why in the hell I thought a stamped sheet metal riding lawnmower needed a deer bumper. It only goes 6 mph.

 

[ironpony]

Only thing I couldn't figure out was why in the hell I thought a stamped sheet metal riding lawnmower needed a deer bumper. It only goes 6 mph.

Ya can't be too careful when it comes ta those infernal critters!

 

[Injun]

Is this a small fleet? How can a mechanic even remember a particular job if it's a big fleet with hundreds or thousands of identical trucks and trailers?

I can't even remember which of the two Goldwings I changed the oil in this spring so I just changed them both last week. And they're not even close to identical.

Nine trucks.

Proper records help with recalling what's done.

We do have that.