Question on Rear Motor Mount Pins -- Can't Remove

[Twolane]

Hate beating my head against a wall on something that should be simple, probably is, but I'm just not seeing. Here's what's up:

A friend brought a spare everything from the motor back. Including the cut out transom. Lots of good spares for the new-to-me Mercruiser 165. Started last night to begin taking things apart and can't get either rear motor mount bolt to come out.

Before he dropped it off he'd started to do the same thing. Had hit both rear mount pins with an impact wrench. The bolt heads are obviously raised up an inch or so. So they've backed off some. But won't come out. I can look up underneath and see captured nuts in the housing on each side. I can see the very end of the bolts spinning inside the captured nuts. But the nuts themselves aren't turning and aren't rounded out.

Am I missing something incredibly simple and stupid here? Or is something screwed up? If the former tell the stupid guy what to do. If the latter please share the least destructive options to getting the motor separated from the transom.

Thanks.

 

[Don S]

Re: Question on Rear Motor Mount Pins -- Can't Remove

You don't mention any years, is this a 6 cyl or 4 cyl 165?

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

You don't mention any years, is this a 6 cyl or 4 cyl 165?

Sorry about that. It's the Chevy inline six. Late 70s vintage.

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove



Hopefully I figured out the way to attach a file here. If so the image in this post is the rear mount scheme I'm working with. The bolts won't come out. Anyone ever run in to this before?

The bolts look to be at the top edge of but not completely removed from the captured nuts. Yet they won't fully remove from the nuts even though they're spinning inside of each of them. Is there a fiber lock or nylock or some other capture mechanism inside the nut that might have broke loose when the bolts were hit with an impact wrench?

Now that I've got a better idea of how this system works may just get beneath it again and try driving the bolts up out of the captured nuts. Unless someone has a better idea....

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Taking one more crack at this thread to see if anyone has run in to the problem before. If no responses will assume no one has seen one behave like this. Hope someone can share something as I'm more than a little gun shy about attempting to lift the motor out of the boat for a winter refresh without knowing why I couldn't get the rear motor mounts apart on this engine with the cut out transom.

Just to refresh; here's the deal.

Inline Chevy 6 (Mercruiser 165) with everything still hooked behind it; including a transom that had been cut out with a chain saw. Friend brought it to just for spares to have for the new-to-me old boat. Vintage is late 70s.

The rear mount is shown in an image a few posts up. It's two "ears" that are part of the flywheel cover with a bolt that goes down through each side. Bolts attach to the piece that attaches to the transom.

These rear motor mount bolts were originally loosened with an impact wrench (if that makes any difference). They backed out a bit less than an inch. After that they just spin. There is a captured nut on each side down underneath. You can watch the bolt spin inside the captured nut on each side. The nut doesn't spin. Just the bolt within it. Same problem on each side.

Bolt is still within the captured nut. Can't be pried or pulled up and out. Couldn't be driven up from the bottom either as it is still apparently within the captured nut. I have no idea what's going on.

Ended up separating the engine from everything behind by taking a rotary cutter to the flywheel cover. Could at least go ahead and finish disassembling everything that way. But the bolts and the bushings they go through are still in that rear piece. Still no idea how to remove them without further tearing things up.

If this is a never-before-heard-of problem perhaps I shoudln't have any reservation later about pulling the engine. Perhaps the rear motor mount bolts always (except for this time) really do just unscrew. If there's some trick (like don't use an impact wrench?) hopefully someone will share. The manual I've got simply says unscrew and remove. But it didn't happen on this one.....

 

[Grub54891]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Sound's like they stripped out,possibly by over tightening at some other point in time. It may be tough to get em out. Or are they unthreaded but bound up a bit,got a pry bar under the head and give it a go....... Sometimes I'll pry up on a bolt and try to spin it out and out they will come!
Grub

 

[mxcobra]

Re: Question on Rear Motor Mount Pins -- Can't Remove

I had to cut one of my bolts off with a metal sawzall blade, when I had this same problem..

 

[ENSIGN]

Re: Question on Rear Motor Mount Pins -- Can't Remove

The bolts are frozen to the inner sleeve of the motor mount.Using a long half inch ratchet and a six point socket just keep twisting until the rubber tears out of the mount.

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

So it's not something that was screwed up by initially hitting them with an impact wrench but is something that occasionally just happens. That doesn't make me feel brave.....

If this happens in the boat how do you get at it to cut the heads off? I thought of that first before ruining the flywheel cover but the casting's shape was such that, even with it all out in the open in the back of a pickup truck, cutting the heads off the bolts wasn't a simple chore. Now I'm wondering if I should've not given up on the effort and saved the cover for spare parts.

 

[ENSIGN]

Re: Question on Rear Motor Mount Pins -- Can't Remove

The last thing you want to do is cut the heads off the bolts.Your impact is not powerful enough to twist the rubber out of the mounts.Before you ruin the inner transom housing heat the mounts and apply a constant twisting motion to them.The rubber will break loose from the inner sleeve and the bolt and sleeve will pull out.

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

The last thing you want to do is cut the heads off the bolts.Your impact is not powerful enough to twist the rubber out of the mounts.Before you ruin the inner transom housing heat the mounts and apply a constant twisting motion to them.The rubber will break loose from the inner sleeve and the bolt and sleeve will pull out.

On this bunch of spare parts I was disassembling the impact would spin the bolt forever. But nothing would actually get the parts separated. Fortunately it was all out in front of me on the back of a pickup truck and didn't have to be good parts. That so many seem to have enjoyed this experience worries the hell out of me though. Maybe a good soak with spray lube before attempting disassembly of the real thing.

 

[81 Checkmate]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Like Ensign said....Aply heat to the bolts to heat the rubber up.

Thats how i removed mine.......Heat and a big a@@@@@s breaker bar to get them to break loose then used my elect impact to remove the bolt.

P.S. Use caution when aplying the heat with the gas fumes.....

Good Luck!

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Thanks gents. There is now at least a plan of action for when the day comes. Hopefully the homework will have been unnecessary and it'll all come apart without a hitch. But I'd rather have a clue....

 

[Speakrdude]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Mine was last ditch effort. HAd to use 4" angle grinder to remove the heads, Motor comes right then. Then the fun begins. Had to drill out the old ones, but at least there is room to get in there and work.

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Mine was last ditch effort. HAd to use 4" angle grinder to remove the heads, Motor comes right then. Then the fun begins. Had to drill out the old ones, but at least there is room to get in there and work.

Especially on the right side (sorry, starboard side) it looks like the bolt head could be a tough get. Bracketry surrounding. Easier to cut the "ear" off the flywheel cover if need. Just in case that ends up becoming the case I opened up my options last night. Scored a spare flywheel cover on eBay for 20 bucks. Too cheap not to have in hand just in case.

 

[Twolane]

Re: Question on Rear Motor Mount Pins -- Can't Remove

Like Ensign said....Aply heat to the bolts to heat the rubber up.

Thats how i removed mine.......Heat and a big a@@@@@s breaker bar to get them to break loose then used my elect impact to remove the bolt.

P.S. Use caution when aplying the heat with the gas fumes.....

Good Luck!

Didn't quite lock in on this until it popped in my head this afternoon while working on another chore. If the bolts sticking within the rubber bushings is the more common problem sometimes experienced that's not what was happening here. In fact the bolts turned within the bushings easily.

Problem here was the bolts were turning within the captured nuts. On both sides. The end of the bolt was flush with the bottom edge of the nut. At that position it just turned inside of it. So a nearly full nut width of bolt was inside the nut just spinning away.

Getting them out of the transom turned out to be easy once the heads of the bolts were cut off. Just lift off the rubber bushings and push everything out the bottom. Pushed out with a finger.

The nuts looked to be of a type with nylon inserts as a locking mechanism. I was assuming the nylock inserts started moving. But I never actually split one of the nuts to find out for sure. Once it did finally all come apart I just said one final bad work and tossed all the scrap pieces in the trash.