Keep breaking motor mount bolts in the block of 5.0L Explorer

[scotts90ranger]

One of several issues with my 5.0L Explorer is when I got it it was missing both bolts into the block for the engine mount on the passenger side... stock bolts were broke off flush with the block and was sitting that way for who knows how long... in the process of removing them since it's pretty tight in there I wasn't as centered as I'd hoped and took out some of the threads so had to up size to 1/2" bolts from 7/16"... I fixed that 20k miles ago, the planetary gears in the trans let go a month ago and while underneath I noticed a missing bolt again and it's broken... When I was putting the transmission back in it was 90F before noon so I wasn't going to tackle that issue in the heat...

I can get the bolt out, that isn't the issue, it's how to fix it so it doesn't happen again... I imagine the issue is the stock bolts were broken for long enough to wear down the block at the engine mount I think, causing the leverage of the mount plate to be extreme since the rubber mount bolt is around 3" or so past the block...

I'm pondering a fix but want other opinions... From what I remember there isn't much over there to add extra bolts to. I'm thinking of welding some parts to the motor mount plate and add another attachment point to reduce the leverage. I'll probably poke around this weekend to see if I can think of something. My only other idea is instead of a flat plate, add a vertical plate perpendicular to meet with the square part of the block.

Ok, I'll stop before I get more long winded... the Whisky might be talking some... But seriously, any ideas are appreciated, this is the least power and abuse this thing will be getting for the rest of it's life... heck, I haven't even been using low range much to put much torque on the mount!

 

[scotts90ranger]

Summation, less whisky tonight...

Breaking passenger side engine mount bolts, block side. Most likely from lots of driving with broken bolts from previous owner (who knows what they did, definitely not mechanics) and wearing down the block increasing the leverage. Anyone have any ideas on increasing the strength of the mount to the block with an extra bracket welded and bolted to another location? Think a grade 8 1/2" bolt would work longer than a grade 5 1/2" bolt?

When the stock front axle goes away, I'll switch to a mount with less leverage, but still interested in ideas...

Thanks,
Scott

 

[bobbywalter]

i usually stud the block. glue em in with red.

depending on what fead your running usually run chains too for back up...not loaded...but long bolt with nylock and washer where there is just some perceptable slack in the chain. people think its ghetto but its effective doing w.o.t. slam fests in low range and using parts store anchor mounts. for a long time i run high tension valve spring too....


the mark 7 mounts are pretty stout though compared to f150 mounts and spacers....assuming your running a factory k member.

 

[alwaysFlOoReD]

BB Ford Torino, I run my chain just snug. From the head down to the frame.

 

[Dirtman]

i usually stud the block. glue em in with red.

depending on what fead your running usually run chains too for back up...not loaded...but long bolt with nylock and washer where there is just some perceptable slack in the chain. people think its ghetto but its effective doing w.o.t. slam fests in low range and using parts store anchor mounts. for a long time i run high tension valve spring too....


the mark 7 mounts are pretty stout though compared to f150 mounts and spacers....assuming your running a factory k member.

How the heak do you get the engine down onto the mounts with studs sticking out!?! Or do you put the studs in after the block is seated to the mounts?

 

[baddad457]

How the heak do you get the engine down onto the mounts with studs sticking out!?! Or do you put the studs in after the block is seated to the mounts?

Very carefully. I used studs on the engines in my 89 Ranger swap. It's a lot easier to align studs into the mount holes than trying to get bolts started from underneath the truck.

 

[baddad457]

Think a grade 8 1/2" bolt would work longer than a grade 5 1/2" bolt?

Scott

Definitely. The O.E. bolts are stronger than grade 5.

 

[Craig0320]

I don't use grade 5 for anything. I have been using grade 8 for years and they are tough. I have seen them worn to half size and still holding.

 

[scotts90ranger]

Ok, I'll try grade 8 first... I just always have a fear of those breaking off and being like the stock studs and not turning out... I don't want to put some red loctite in there yet, once I get a mount that's closer to the block I'll go that route... There's not a whole lot of room to deal with the motor mount bolts on a SLA V8 Explorer at stock height with everything there, when I got the originals out I had a 90* air drill, safety glasses and safety squints engaged while on a creeper trying my darndest to keep things straight and just had enough room... still had to tap to 1/2"...

Ok, if you guys have good luck with grade 8, I'll start there, I just haven't used them much, we use grade 5 for silly things at work and it always works...

Bobby, stock everything in this Explorer so far except the 4406 swapped in, next year most likely will be on super duty axles and somewhere around 40" tires... sometime hopefully it will become a 347, the 4R70W should hold up to it at this point as it has been gone through...

 

[85_Ranger4x4]

How the heak do you get the engine down onto the mounts with studs sticking out!?! Or do you put the studs in after the block is seated to the mounts?

Straight down.

 

[baddad457]

Ok, if you guys have good luck with grade 8, I'll start there, I just haven't used them much, we use grade 5 for silly things at work and it always works...

You can't trust anything in grade 5 now-a-days. The armrest stop bolt in the seat in the Mack truck I drive snapped off the other day just by my leaning on the rest climbing out of the sleeper. And this was a 7/16" bolt. When in doubt, use a grade 8 or 9 bolt.

 

[scotts90ranger]

Replaced both bolts today...

Apparently I didn't tap both bolts the first time to 1/2", the front bolt was still 7/16" which was unfortunate because I bought two 1/2" bolts the first time around, things went "twang" and lost one of the two bolts, went to the hardware store and grabbed another 1/2"x1" bolt (2 this time), go to put it in (now raining) and realize that bolt is 7/16", drive the 15 miles BACK to town, get 6 7/16 grade 8 bolts (don't have 7/16" on hand of any grade) and now it's together...

I might have had the bolts too long last time, the one bolt was broken (the 7/16" bolt) and the other (1/2" bolt) was bent, the pad for the rear bolt (1/2") is worn down at an angle from the previous break and isn't helping anything.

Anyway, fixed for now, we'll see how that goes, found the front exhaust manifold bolt was not even finger tight and has been leaking so I tightened that while I was there...

 

[scotts90ranger]

Just an update, so far so good with the new bolts. Looks like issue solved, must have been off on my bolt lengths before...