Rear frame cover bolt holes damaged--HELP!

[FRED VACCARO]

I was installing a rebuilt hydraulic cylinder for the three point system at the rear of the tractor and I noticed the one of the bolts that attaches the top link rocker bracket to the rear frame cover was loose. I tried to tighten it but I found that the threads in the cover where stripped out. I remove the other two bolts and found more problems. All three of the bolt holes were broken at some time before I owned the tractor.

My question is: what kind of a fix can I do to repair this problem without removing the cover plate?

I think that the cover plate is cast iron and I assume that the only weld that would work would be brazing?

One idea that I thought of was to drill out each hole area and thread a larger bolt into the cover--then drill that bolt out to make threads so I could use the same size bolts as originally installed?

Another thought was to make a metal plate large enough to cover most of the cover plate and weld the top link use the smaller bolts to hold down the top link,

Any suggestions are appreciated--

 

[Janicholson]

I think using the next size larger bolts, and redrilling the rocker bracket is best. I also don't like the top link rocker
bracket as it is. There needs to be flat spots (spot face) where the bolt heads touch the flat plate. With a bigger bolt,
and using socket head cap screws it will work. It appears that there is little clearance for the bolt head, and that might
take a bit of rework to make that happen. Putting an aluminum plug in the existing holes either threaded in and cut off, or
tapped in if machined to the minor diameter of the broken holes, will allow controlled re-drilling for larger bolts. Don't
drill through!. I would also drill and tap smaller holes on the corners of the rocker bracket to allow 3/8 setscrews to be
screwed in to touch and support the corners of the rocker plate. A standoff should be made to be placed on the cover bolt
(centered between the two broken holes) to allow that bolt to be used for support as well. Another way to get this done is
to grind off the broken areas to flat, and drill/tap them oversized from there. Then use standoffs on all 4 as above. Jim

 

[used red MN]

I agree with Jim about just rethreading to the next size
larger bolts. Due to the mis-engineered placement of the
plates that raise up for the pin to go through his idea of a
socket head bolt is very good. Also as he suggested
grinding an area of the weld to allow the rear bolts to
torque down well is also a good idea. Maybe even
acquiring some machine washers and grind off the side to
fit it the area of the weld you ground away. What I would
recommend to add would be a 3/8 in. thick 1 1/4 in. angle
iron that would cross between the two cover bolts that are
along each side of the cover. You will need to get another
bushing and longer bolt as shown on the left one. Bolt that
down with the lip towards the back. Then get a couple of
3/8 x 1 in. flat bars 2 - 3 in. long, what ever seems to fit
well. These will be laid on either side and be welded on
extending forward to also be welded to the back of the
angle bolted between the cover bolts. The reason for this is
the front single bolt is taking most of the force in this
configuration. Adding the extra anchors points to the front
side will ensure the unit stays properly attached and stays
tight. If this does not make sense I will try add some
reworked photos to better explain my suggestion. I am not
sure by the photos what the difference is between the
centerline of the two cover bolts and the front mount bolt of
the pad. If there is not enough front to rear distance this may require variations in how it would all layout.

 

[kossuth]

This post was edited by kossuth on 06/17/2021 at 06:06 pm.

 

[Janicholson]

Good idea on the cross member at the front, I would make the spacers at the front two extra bolts 1/16 thinner than needed to preload downward on the plate on each side. Jim

 

[kossuth]

(quoted from post at 11:00:20 06/17/21) I was installing a rebuilt hydraulic cylinder for the three point system at the rear of the tractor and I noticed the one of the bolts that attaches the top link rocker bracket to the rear frame cover was loose. I tried to tighten it but I found that the threads in the cover where stripped out. I remove the other two bolts and found more problems. All three of the bolt holes were broken at some time before I owned the tractor.

My question is: what kind of a fix can I do to repair this problem without removing the cover plate?

I think that the cover plate is cast iron and I assume that the only weld that would work would be brazing?

One idea that I thought of was to drill out each hole area and thread a larger bolt into the cover--then drill that bolt out to make threads so I could use the same size bolts as originally installed?

Another thought was to make a metal plate large enough to cover most of the cover plate and weld the top link use the smaller bolts to hold down the top link,

Any suggestions are appreciated--

ou could also helicoil/timesert it. Personally thats how I would do it. The helicoil/timesert is going to have way more strength than retreading the casting. Either way you are drilling and tapping the iron. As Im sure you know the proper way to do this is to pull the cover so you dont get debris inside. I know why you dont want do you so in light of that you want to approach this as smart as possible. You want to flush the rear once your done. I would also drill and tap super slow and use some sorta grease. Basically as you drill and tap you want to pack the flutes of the drill/tap with grease so it catches as much of the shavings as possible. Your gonna get some shavings inside the casing but this will get most of them.

 

[wore out]

Have you tried to find a good used cover at a decent price?3
With the type of damage yours has that's what I'd try to do ESPECIALLY if you will be using the 2-point.

Also, it looks to me like the welds on the bracket are so close to the holes that it would be impossible to tighten them properly.

Might have to grind off a bit of weld next to the holes, then use Allen head capscrews.

 

[FRED VACCARO]

Thanks for everyone's replies!

I removed the plate that is attached to the upper cover and I found that the previous owner had installed bolts that were not long enough. There were still threads in the bolt holes that were not being used.

I ran a tap down into the three holes and cleaned everything up. I then made three new bolts that went all the way into the holes. I also repositioned the holes on the plate that attaches to the cover (they were never straight to begin with) . Every thing seems to be good at this time--I will need to keep an eye on anything and if there is a problem I will go to plan B !

I still need to install some rubber hoses over the new hoses where they rub against the metal plates etc.

This post was edited by FRED VACCARO on 06/25/2021 at 11:54 am.