Over tightened Cap Screw!

/ Over tightened Cap Screw! #1  

Piedmont

Silver Member
Joined
Mar 28, 2006
Messages
181
Location
NC, USA
Tractor
JD 2520
I over tightened one the cap screws (D) when changing the transmission fluid. I removed the
Suction screen cleaned and reinstalled. I have since lost the cap screw, it must have vibrated off. Is there an inexpensive repair that I can tackle my self or is this a dealer issue? Any help will be appreciated.

MX12150, MX12314
5. After oil is drained, remove two cap screws (D), two lock washers (E) and suction screen cover (F).
 

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/ Over tightened Cap Screw! #2  
???? Did you over-tighten and break it off or did it get loose and fall off?
 
/ Over tightened Cap Screw!
  • Thread Starter
#3  
Over-tighten and got loose and fell off?
 
/ Over tightened Cap Screw! #4  
Are you saying that you overtightened the bolt and damaged the threads in the case? If so, it's time for a heli-coil insert. If you have a power drill you can do this repair yourself. No expensive dealer visit required. Check with your local auto parts or tool store a kit that includes the drill bit, tap, inserts and insertion tool. All you need to know is the bolt diameter and thread pitch. If the tap will not pass through the cover you will need to remove it and then refill your gearcase. Please let us know what happens.
 
/ Over tightened Cap Screw! #5  
Are you saying that you overtightened the bolt and damaged the threads in the case? If so, it's time for a heli-coil insert. If you have a power drill you can do this repair yourself. No expensive dealer visit required. Check with your local auto parts or tool store a kit that includes the drill bit, tap, inserts and insertion tool. All you need to know is the bolt diameter and thread pitch. If the tap will not pass through the cover you will need to remove it and then refill your gearcase. Please let us know what happens.

^^^^^^^^^^
What he said. If the case is stripped then a helicoil is the best solution-and I would do both just to be safe.
 
/ Over tightened Cap Screw!
  • Thread Starter
#6  
Are you saying that you overtightened the bolt and damaged the threads in the case? If so, it's time for a heli-coil insert. If you have a power drill you can do this repair yourself. No expensive dealer visit required. Check with your local auto parts or tool store a kit that includes the drill bit, tap, inserts and insertion tool. All you need to know is the bolt diameter and thread pitch. If the tap will not pass through the cover you will need to remove it and then refill your gearcase. Please let us know what happens.

Exactly, I damaged the threads in the case. Thank you I will go this route for sure. I appreciate everyones feed back
 
/ Over tightened Cap Screw! #7  
Sometimes it might be easier to tap the hole for the next size bolt... all depends on what you have to work with...
 
/ Over tightened Cap Screw!
  • Thread Starter
#8  
Are you saying that you overtightened the bolt and damaged the threads in the case? If so, it's time for a heli-coil insert. If you have a power drill you can do this repair yourself. No expensive dealer visit required. Check with your local auto parts or tool store a kit that includes the drill bit, tap, inserts and insertion tool. All you need to know is the bolt diameter and thread pitch. If the tap will not pass through the cover you will need to remove it and then refill your gearcase. Please let us know what happens.
I'm just starting to do my reasearch. Would I want to use the free running type or the screw lock type? Also which finish? dry film lube or no finish? The bolt is M8X20, how do I determine if it is a fine thread or a coarse?
You may have figured this out already but this is new territory for me and I want to get it right the first time!
 
/ Over tightened Cap Screw! #9  
Sometimes it might be easier to tap the hole for the next size bolt... all depends on what you have to work with...

I wouldnt reccomend that...in the future this "could" happen again.... HeliCoil is the way to go...same size bolt, AND a HeliCoiled insert is usally STRONGER then a plain tapped hole in aluminum. Thats why most hi-perfomance heads like Edelbrock come FACTORY with helicoiled inserts.
In the racing community I've also seen people helicoil the valve cover bolt holes on aluminum heads because the aluminum just doesnt stand up the repeated removal/reinstallation...with helicoils they last forever...

Because this is a "commonly" removed part, I'd probably go ahead and helicoil both of them and be done with it...
 
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/ Over tightened Cap Screw!
  • Thread Starter
#10  
I'm just starting to do my reasearch. Would I want to use the free running type or the screw lock type? Also which finish? dry film lube or no finish? The bolt is M8X20, how do I determine if it is a fine thread or a coarse?
You may have figured this out already but this is new territory for me and I want to get it right the first time!
 
/ Over tightened Cap Screw! #11  
I wouldnt reccomend that...in the future this "could" happen again.... HeliCoil is the way to go...same size bolt, AND a HeliCoiled insert is usally STRONGER then a plain tapped hole in aluminum. Thats why most hi-perfomance heads like Edelbrock come FACTORY with helicoiled inserts.
In the racing community I've also seen people helicoil the valve cover bolt holes on aluminum heads because the aluminum just doesnt stand up the repeated removal/reinstallation...with helicoils they last forever...

Because this is a "commonly" removed part, I'd probably go ahead and helicoil both of them and be done with it...

If it is a through hole a bolt and nut would be the simplest...

At the machine shop we seldom used helicoils... almost every job spec used a threadsert product that had built in tangs to lock the insert into place...
 
/ Over tightened Cap Screw! #12  
If it is a through hole a bolt and nut would be the simplest...

At the machine shop we seldom used helicoils... almost every job spec used a threadsert product that had built in tangs to lock the insert into place...

I must apologize...I use the word helicoil similar to Kleenex & QTips....When I say Helicoil I dont mean a specific brand/style/part, etc...
I recently used some Recoil brand "Keyserts" and I thought those were really slick & nice...
 
/ Over tightened Cap Screw! #13  
I must apologize...I use the word helicoil similar to Kleenex & QTips....When I say Helicoil I dont mean a specific brand/style/part, etc...
I recently used some Recoil brand "Keyserts" and I thought those were really slick & nice...

No apology necessary... Keyserts is the name I couldn't remember... thanks for the info!
 
/ Over tightened Cap Screw! #15  
I'm just starting to do my reasearch. Would I want to use the free running type or the screw lock type? Also which finish? dry film lube or no finish? The bolt is M8X20, how do I determine if it is a fine thread or a coarse?
You may have figured this out already but this is new territory for me and I want to get it right the first time!

This is what a kit looks like: M8 Helicoil. It does not come with a drill bit though...There are plenty of similar product on the market, some of which I am sure you can source locally. Try a google search of "m8 thread repair" for thousand of hits. Some "kits" do include the drill bit also. Most likely it is a 1.25 course thread.
 
/ Over tightened Cap Screw! #16  
This is a cover...how the heck would he get a nut on the backside if it was a through hole:confused::confused::confused:

Some automotive auto transmission pans have the pan bolts going through a flanged lip... some of the bolts go into blind holes and some in through holes with the threads visible on the outside of the case...

I've never worked on any John Deere larger than a garden tractor... just mentioning different possibilities to work around a stripped bolt hole...
 
/ Over tightened Cap Screw! #17  
I'm no expert, but I have put a few heli coils in. I might suggest you make a jig for the drill to keep it perfectly straight, and so it does not wonder and make a larger hole than you want. If you have a drill press you can make somthing that will secure with the good bolt, and make sure this hole is at a 90 degree angle with the flat part.

Wayne
 
/ Over tightened Cap Screw!
  • Thread Starter
#18  
Thanks all, I won't get to this until the Thanksgiving weekend but I will post at update. Is there a way to find out if the 8MX22 cap bolt is a fine or coarse thread?
 
/ Over tightened Cap Screw! #19  
Is there a way to find out if the 8MX22 cap bolt is a fine or coarse thread?

Not easily, but you can assume it's the course 1.25 thread. Most are-especially when used in aluminum.
 

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