Bobcat 773: "Mystery Part"

[DrJim]

Now, Willie, a couple of questions for you. You remember that I found the spacer just laying there, but. . . there is no telling if there was another spacer or washer added to that one, in between the bracket and the pump block. The question is, should be use the one spacer, and pull the mount bracket up tight, should we make up spacers that mostly fill the gap first, or should be maybe add a washer-spacer to fill maybe half the gap and pull it up tight from there? Of course, we would select the optimum length bolt to engage as much of the threaded hole as possible without binding or bottoming.

Another Willie question: I don't want the bolt to work its way out, but if we use red threadlocker and the bolt breaks again, we are back to the same problem of trying to retrieve the broken segment. I am inclined to skip the threadlocker and tack-weld the edge of the bolt head in a very small spot. That will keep the bolt from backing out, and if the bolt breaks, the tack could be ground off, the head would fall off, and the bolt could be more easily retrieved.

This would also prevent the broken head-end of the bolt from finding its way under the plastic fuel tank, where it could rub a hole. Whaddaya think, Ol' Morooka Man?

 

[lantraxco]

Feh, you guys call yourselves experienced mechanics? It's simple, you just make sure nobody's watching, tie the pump in place with a ratchet strap, throw the spacer as far away as you can, preferably in some weeds or bushes, then quickly lower the cab and walk away. I know this must be the correct procedure because I have found several different make and model machines where this repair seems to have been performed, as the ratchet straps are all faded and oil soaked.

 

[willie59]

Nice crafty work Dr Jim. :drinkup

And I don't see a problem with securing the bolt head instead of using thread locker on the threads. Of course, there's always plan B mentioned by the real Morooka Man above.

 

[crewchief888]

the correct bolt comes with thread locker already applied....



:drinkup

 

[DrJim]

That's just great, crewchief888. (and where is "NWI"? Northwest India? ) Make it impossible to remove the bolt when it breaks the next time. The Bobcat dealer wanted to "pull the motor" to get the broken bolt out. Waiting a year or more for the Tom Sawyer method was better for me.

This bolt breaking seems to be a common problem. Do they break because they loosen first, just break, or. . . both?

Y'all didn't yet answer my remaining question: Should we make up a spacer thickness that fills all or most of the passive gap between the mount bracket and the pump, use the one spacer that we know fell out, or what? Being fundamentally ignorant, I have no idea what determines the alignment of the pump mounting.

When I get the spacer thing and bolt torqued up, I'm gonna start working on my face. Maybe start a thread?

 

[willie59]

Bobcat should be able to look up the proper spacers by the serial number, but yes, you want to fill that gap between the bracket and the pump housing. And I'm not sure exactly what breaks that bolt, some do, some don't, go figure, my best guess is not torqued to proper spec in the first place. As for crewchief, I can assure you he's not from North West India, he's a genuine Bobcat technician, and a really handy fellow to have here at HEF, his contribution of helping folks with Bobcat machines here is much appreciated. :drinkup

 

[DrJim]

Yes, Willie, I can tell the man is alright. I have heered of Knoxberg where you lounge about. I can git there by follerin' the Dixie Highway. I was honest to gosh wondering where NWI really is, not being mean. I might want to visit someday. . . I've been known to show up and buy HEF members a really fancy lunch--I once paid as much as $ 6.00.

Ever had that happen, Willie? :beerchug

I tried to look it up. http://acronyms.thefreedictionary.com/NWI
NWI could be Northwest Indiana; Norwich, England; Netherlands West Indies; Nowhere Interesting; National Women's Institute: or most anything.

Bobcat shows 3 or 4 different combinations of spacers and washers and different bolt lengths. I think the exploded diagram is wrong, as it shows the spacers between the head of the bolt and the outer side of the bracket, not between the bracket and the pump housing. My machinist friend can make a spacer to fill the gap, and we can gauge the hole depth.

The hole in the pump housing is blind, not through, on my pump. If the factory used a bolt a fraction too long for the make-up, that might explain the bolt breakage.

Working in hay today. . . need to figure out why the JD 5425 farm tractor loses its prime when it sits for a few weeks. The primer pump is on one side of the tractor, and the bleed on the injector pump is on the other side. That's a real hassle--darn near impossible to do efficiently by yourself. Fuel line check valve or something silly in the Stanadyne primer assembly is causing it. Point me to a good thread or two for that, or I will start one.

Thanks to you all for sharing with me, for encouraging me to be smarter than that bolt.

 

[mitch504]

National Women's Institute could be a wonderful place to live; or, next door to hell.

 

[willie59]

Mitch, you have a funny (albeit twisted) sense of humor. :falldownlaugh

 

[mitch504]

Thanks (I think)

 

[lantraxco]

Here's a silly suggestion if at all in doubt about the bolt length..... use a stud and a nylock nut. Gently bottom the stud so you're sure of full thread engagement and I would use thread lock on it. For whatever my opinion is worth, lol.

 

[DrJim]

Good idea, lantraxo, one that I need to remember for other applications. Though I like Nylock nuts for some things, I find that they are weak compared to Grade 8 nuts. I also loathe the idea of threadlocker on the bolt threads. Breakage of these pump-mount bolts seems to be common, and I want to be able to retrieve the broken end if it breaks again. I am inclined to put anti-seize on the bolt threads, and then tack-weld the head of the bolt to the washer, and the washer to the bracket after torqueing it. That will make it 100% "locked tight" but still retrievable by simply grinding the tack weld. Unless, of course, one of you talks me out of that.

By day I work with Titanium dental implants, essentially threaded inserts with various attachment components (see Zimmerdental.com). For kicks, try removing a 1.25 mm Ti screw (broken off) through a tiny access hole drilled through a maxillary molar crown. Great fun, but doable. Fortunately, the system I use is not plaqued with screw breakage like other products in the implant industry. Thanks for the suggestion, 'traxo.

 

[lantraxco]

Personally I would avoid welding the actual bolt, welding a flat or square bar in place tight against one flat I would go for, but to each their own of course. As far as locknuts, I use either Grade 8 nylocks or Grade C locknuts, these are the all metal ones that are crimped for an interference fit, they're not really designed for reuse.

Let us know how it works out for you.

Btw, I could use some dental implants myself, I suppose a DIY kit is out of the question? :tong

 

[DrJim]

Part of the reason I wanted to tack the bolt head itself is to keep it from falling under the fuel tank, finding its brother, and together rubbing a hole in the plastic fuel tank. Just seems like the tiniest of tacks--head to washer and then washer to bracket--would keep the bolt from turning out. Welding a bar tight against the head seems like it would take more welding. . . and thus make it harder to get back apart.

But while we are discussing this, I just realized a significant drawback to my idea: If the head is tacked to the bracket and the bolt somehow breaks anyway, you won't be able to tell that the bolt is broken. It will look good, but might not be providing any support.

I'll consider your suggestions re: welding a bar or retainer tab. I don't have much experience with that, but have one or two creative fabrication experts who do have. Can you post a photo of an examples of what you suggest?

I guess I could drill the corner between two flats on the bolt head. . . and safety wire it, like on a race bike.

 

[lantraxco]

How about a flange head bolt and a bolt on retainer plate, if you have the room?

Pictures not to scale, lol.

 

[sims]

X2 on the safety wire solution. Doesn't require any additional fabrication and it will allow you to use anti-seize in the initial assembly. BTW does the bolt break because it loosens and then gets beat up or is it undersized for the application? Just curious.

SimS

 

[fixou812]

...."from time to time I would wak tthrough the shop t

 

[fixou812]

"....from time to time I would walk through the shop to Visit him. If he wasn't looking I would....."
Dr. Jim you Green eyed double headed Gemini looking miscreant Monster!
That was so wrong after reading I began to weep.
Hope you found what you were searching for.
I'll Remember you in my prayers.
Sincerely, fixou
P.s. tell your wife and my kids I said hello

 

[willie59]

"....from time to time I would walk through the shop to Visit him. If he wasn't looking I would....."
Dr. Jim you Green eyed double headed Gemini looking miscreant Monster!
That was so wrong after reading I began to weep.
Hope you found what you were searching for.
I'll Remember you in my prayers.
Sincerely, fixou
P.s. tell your wife and my kids I said hello

fixou812, I figured out that you're quoting a post by Dr Jim in post #2, and the quote cuts the original text short as indicated by the (...) periods, meaning, some of the context of the post isn't obvious. Forgive me for being dense, but I'm trying to figure out your post and quoting Dr Jim (without actually using quotes). I'm thinking there has to be some form of humor there, at least I hope, but for the life of me I just don't get it. Could you enlighten a knuckle dragger like me as to what the inside joke is? After all, your reply dose get a little personal. :beatsme

 

[fixou812]

Dear Dr Jim, I'm sorry for teasing you seems I was flashing back to someone messing with my bolts Lol.
Oh and Willie I must refrain from posting with a hangover!