Broken frame to engine bolts

[Jenkins003]

I have a Century 3040 (same as Branson 4020 I believe). While working on the fuel solenoid which doesn't retract since the boot is broken I noticed the two front bolts on the frame which appear to go into the engine are broken. The rest of the 6 bolts were loose. I tightened the remaining 6 and they don't appear to be stripped. Am I going to get into any kind of trouble if I try to drill the broken bolts out and retap for new bolts ? If I wasn't going into the engine I wouldn't worry. Any other suggestions of how to get the broken bolts out would be appreciated.

 

[shovelmike]

Center punch as close as possible to the center, get some high quality left hand (counter clockwise) drill bits. I was in a similar situation recently, and drilled with a conventional right hand bit followed by easy out, was not successful. I used a CCW bit, it dug in and spun the bolt out immediately. I followed up by running the proper tap into the threads to "chase" them, clean them up a bit.
Success!

 

[Roadworthy]

You've probably already looked for the easy way out, but where are the bolts broken? Did they break flush with the block or hopefully closer to the head? If you have a stub sticking out you may be able to remove the solenoid to get Vice Grips to lock onto the stubs. Just a thought. Otherwise, yeah, go with the left hand bit.

 

[mrmikey]

Once you get the bolts out, run a tap thru the holes, see if you can use longer bolts without bottoming out. Regardless, get new gr10.9 bolts and 10.9 flats, no lockwashers and use Loctite when you put the bolts in. If the bolts have been used loose they're shot as well might be the tapped holes, they may be egg shaped or just worn from being loose......Mike

 

[Diggin It]

Am I seeing that you have to work THROUGH the frame rail to even get to the broken remains?

 

[mikester]

I have a Century 3040 (same as Branson 4020 I believe). While working on the fuel solenoid which doesn't retract since the boot is broken I noticed the two front bolts on the frame which appear to go into the engine are broken. The rest of the 6 bolts were loose. I tightened the remaining 6 and they don't appear to be stripped. Am I going to get into any kind of trouble if I try to drill the broken bolts out and retap for new bolts ? If I wasn't going into the engine I wouldn't worry. Any other suggestions of how to get the broken bolts out would be appreciated.

Sometimes you get lucky and the stud is sheared off flush or proud of the block. Another trick is to place a nut over the stud and weld the stud to the inside of the nut. Failing that drill it out. Start with a small bit first and keep stepping up in drill sizes. At some point it with either self drill out or get an easy out tap. Be patient.

 

[flyerdan]

Being recessed in that thick framework, a couple options are using a transfer punch to get a center mark to drill; if the break is jagged get in there with a rounded carbide burr and smooth the center out so the drill bit won't wander. Another option would be to use a drill guide, they are very hard, like valve guides, made for fixtures. If you find one that's close it can be shimmed up with tape or something to temporarily hold it in the frame hole. It's not like it has to stand up to repeated uses, but it will give you a dead center hole with no bit travel.

 

[mrmikey]

If you cant drill it and have access to a welder, build up the bolt and then weld a nut to the stub you've built up. A piece of copper pipe in the hole will prevent sticking top the loader pieces. I don't think it will come out too hard unless the threads are really monkeyed up.................Mike

 

[ruffdog]

A high quality LH drill and a high quality ez-out. Use the correct sizes and drill as straight as possible. Use common sense....don't drill through the block.

 

[Jenkins003]

I do have to work through the frame so there is no way to weld anything to the bolts.. The bolts broke off on the back side of the frame. I'm going to try a tranfer punch and then some left handed drill bits none of which I have purchased yet. I haven't taken one of the remaining bolts out to measure yet but I'm going to guess they are around 7/16 but in a metric size. My machinist friend told me to use an EZ out but I think I'll try the left handed drill bits first and have an EZ out on hand also. I can't figure what caused all the bolts to loosen which I would assume is what caused the front bolts to break. I don't have a front end loader so the front couldn't have been overloaded. I changed the fuel filter just a couple of months ago and the bolts were fine then. The only thing I have done since then is some bush hogging.

 

[Diggin It]

I can't figure what caused all the bolts to loosen which I would assume is what caused the front bolts to break.

There have been a bunch of threads discussing various bolts and nuts loosening due to vibration (apparently) and many owner's manuals include inspecting and torquing them periodically.

 

[ruffdog]

I'm thinking that you have 12mm bolts which is slightly less than 1/2". I would start with a 3/16" drill in the center, then use the correct ez-out. Most of the time I will use a smaller drill as a pilot drill before the final size. Just get a good center punch to locate the center first.

 

[Jenkins003]

I took one of the bolts out this evening and ruffdog you are probably correct on the 12mm size. It is around 7/16 by 1 1/2 inches long. I'll try your suggestion of starting with the 3/16 drill bit. I looked at the tractor frame and it appears as a last resort the frame rail on that side would come off but it would be a big job but I believe I can get the broken bolts out without going that far since there is no reason for them to be frozen in there. It may be several days before I get the time to try to get them out. Harbor Freight has a set of transfer punches so I'll pick them up tomorrow and try to find somewhere to buy some quality drill bits and EZ Outs.

 

[5030]

Center punch as close as possible to the center, get some high quality left hand (counter clockwise) drill bits. I was in a similar situation recently, and drilled with a conventional right hand bit followed by easy out, was not successful. I used a CCW bit, it dug in and spun the bolt out immediately. I followed up by running the proper tap into the threads to "chase" them, clean them up a bit.
Success!

Modify that a bit... Use a proper diameter transfer punch and get the punch mark DEAD center.

Apply some thread locker when you replace them and torque properly.

 

[Jenkins003]

Does anyone know what these bolts should be torqued to ?

 

[5030]

Should be a bolt torque chart in your owners manual. If not, post the diameter and thread pitch as well as the strength of the replacement bolt and I'll look it up for you.

 

[Jenkins003]

It appears these bolts are grade 10.9 and the bolt also has an H5 stamped on it if that means anything. They are 1 1/2 inches long and my owners manual has no torque specs.

 

[Tomtint]

It appears these bolts are grade 10.9 and the bolt also has an H5 stamped on it if that means anything. They are 1 1/2 inches long and my owners manual has no torque specs.

Torque them a little less than the last guy did ..lol

 

[mikester]

Torque them a little less than the last guy did ..lol

No, torque them properly and save yourself very expensive repairs

Heres the Kubota specs for a starting reference

 

[5030]

The H5 is the maker's mark and the posted chart will suffice for torque values. I would apply s tab of threadlocker to them as well. Preferably red, high strength.