big motormount problem

[whatusername]

this car is costing me alot of money.. i have a problem with the rear engine mount. its not connected to the transmission because the IDIOT po some how managed to break 2 of the 3 bolts off flush in the tranny and break the ear off the 3rd one so i have no way of mounting the motor mount.. i attempted to drill out 1 of the bolts then use an ez out n broke the ez out in the bolt.. i managed to get the ez out out but the broken bolts are still there. i didnt wanna drill all the way thru the bolts cuz i do not know if i would wind up in the transmission and damaging it. has anyone taken these trannys apart? do u know if i can drill all the way thru and not damage anything? or can that casing be changed? i have solid mounts on the front and pass side but the front one is already breaking apart from all the engine rocking. Any help would be appreciated.

 

[blkspdfreak]

damn....that sounds like a headache.....if tapping it out doess not work im not sure. can it be welded? i'd hate to drop the whole tranny, take it apart just to find out it cant be done. that sucks man.....

 

[whatusername]

who u telling... when i had the tranny out was when i tried the drilling and got about half way thru 1 bolt but was afraid to go further for fear of damaging the inside of the tranny.. but now that the trans is on im sure its gonna be even harder to do

 

[xxxmonoxidechil]

Was it a shop that tried to install the mount? If so then legally they Have to fix what they broke.

 

[whatusername]

no the mount was always there but not connected the previous owner beat the hell out of this car n somehow broke the bolts in the tranny and 1 of the ears too

 

[xxxmonoxidechil]

Ah, Previous owner. Well the way id go about fixing this. and have done in very similar cases a few times and has worked is to drill out the snapped off bolt. You will have to do it in a few steps, using different sized bits, and just going up bit size, by bit size. You dont need to drill it out to its original full size. 90% of the time you can stop at just under the original size of the hole. And by then u can use a small flat head or pick, and flake away the remaining metal left behind, then you dont even have to re-tap it, You just re-use the original threads. You do need to have your first drill hole centered to make this work the easiest though. But isnt absolutely needed either.

 

[whatusername]

Ah, Previous owner. Well the way id go about fixing this. and have done in very similar cases a few times and has worked is to drill out the snapped off bolt. You will have to do it in a few steps, using different sized bits, and just going up bit size, by bit size. You dont need to drill it out to its original full size. 90% of the time you can stop at just under the original size of the hole. And by then u can use a small flat head or pick, and flake away the remaining metal left behind, then you dont even have to re-tap it, You just re-use the original threads. You do need to have your first drill hole centered to make this work the easiest though. But isnt absolutely needed either.

like i said in the irst post i tried drilling it but didnt wanna go thru the trans so stopped at mayb 1/2-3/4 way thru then used an ez out n broke it in there was able to get it out but the bolts still in there.. i will get some pics when it stops raining

 

[xxxmonoxidechil]

Yea, like i said, you have to drill it out using multiple bits. Going up a size at a time. Then once you near the original threaded wall part, but just a size under it, you can chip away the remaining chunks of the broken bolt. Ive done exactly this easily a dozen times on different projects or fixing snapped off bolts for friends.


The way to tell how deep to drill a hole, and when to stop is just take a basic piece of tape. And wrap it around the drill bit at the point you want to stop. This works for drilling into heads and blocks also so you dont risk drilling into coolant ports or anything like that. To know how deep to drill, I just take 1 of the good bolts, then use that as a measurement for how deep to go. You dont need to measure it or anything though, just hold it up next to your drill bit. And wrap the tape around the drill bit where the head of the bolt is.

 

[whatusername]

Yea, like i said, you have to drill it out using multiple bits. Going up a size at a time. Then once you near the original threaded wall part, but just a size under it, you can chip away the remaining chunks of the broken bolt. Ive done exactly this easily a dozen times on different projects or fixing snapped off bolts for friends.


The way to tell how deep to drill a hole, and when to stop is just take a basic piece of tape. And wrap it around the drill bit at the point you want to stop. This works for drilling into heads and blocks also so you dont risk drilling into coolant ports or anything like that. To know how deep to drill, I just take 1 of the good bolts, then use that as a measurement for how deep to go. You dont need to measure it or anything though, just hold it up next to your drill bit. And wrap the tape around the drill bit where the head of the bolt is.

makes sense i will try that later when get the chance

 

[P-Funk!]

^Make sure you allow for the depth of the mount - don't drill the entire threaded length

 

[pcb]

Make sure the two broken bolts are the same length as the one that's left.

 

[ihone]

possibly weld bolts onto the ends of the broken stubs so you can get a wrench on to take them out?

Works for our stuff in the field all the time.

 

[mp5la]

Welding works. Sometimes if there's a little bit of the bolt still sticking out, you can just chuck the drill onto the bolt stub thats sticking out and back it out that way. Otherwise you could use a dremel or small grinder and try putting a slot in it that would fit a large flathead. Be sure you're using a good penetrating catalyst (pb blaster or kroil) before you try to back it out.

I'd imagine the previous owner broke the bolts while trying to change the transmission mount since it's notoriously difficult to get at.

 

[whatusername]

nope bolts are broken off under flush no way to weld a bolt to it at all drilling will be the only way n its gonna be tedious and probably ruin alot of expensive bits in the process.

 

[ihone]

if it's broken under-flush, then drill that bad-boi out and get yourself one of those BIG bolt extractors.

I bought one at ACE hardware for 8 bucks that worked on my broken trans case bolt (14mm head x 1.25 pitch x 120mm length)

 

[whatusername]

i did that when the trans was out n broke that big ol bolt extrator lol but i will try iy again hopefully on sunday if it dont rain

 

[whatusername]

Okay so I am going to attempt broken bolts again what kind of drill bits should I use? Remember these are grade 8 bolts so what kind of bits work best and what speeds should I drill at?

 

[JDM323J48]

get some cutting lube to spray on when drilling, not sure on bits and speed, if it was me I would ask at an engineering shop they will know for sure.