View Full Version : Removing Crankshaft Bolt on 4.0l

April 24th, 2012, 18:48
I cannot seem to break it loose, I google and google, and get no speed specific info on a special took or anything I can do to break it loose.

Motor is out of jeep sitting on the ground. I tried a screwdriver in the balancer to no avail, I tried a pry bar too.

Any special tools or tips or tricks?

April 24th, 2012, 18:57
I use an impact wrench.

April 24th, 2012, 20:16
I have a air compressor, but its small and dont even break lug nuts usually. Ill give it a try tomorrow.

April 24th, 2012, 20:19
You don't necessarily need a large compressor, but you do need a good impact wrench and a tank of air. If you're cheap (like me), you might try one of the "earthquake" impact wrenches from HF.

April 24th, 2012, 20:47
an impact is the best way, but if you are in a bind you can put a box end wrench on it, apply a little pressure with one hand, then give the wrench a smack with a hemmer. it should give the shock hard enough to beak it loose. even pressure just turns the crank. you need the shock force.
i just took mine off to replace a timing chain. no room for an impact so i drilled a hole in the bumper just behind the lic. plate. put a socket on the bolt, stuck a long extension through the hole and hit it with an impact. flew right off. now i just need to find out how tight it needs to be when i put it back on. anyone know the torque spec?

April 24th, 2012, 20:51
from the manual

(1) Apply Mopar Silicone Rubber Adhesive Sealant to the keyway in the crankshaft and insert the key. With the key in position, align the keyway on the vibration damper hub with the crankshaft key and tap the damper onto the crankshaft.
(2) Install the vibration damper retaining bolt and washer.
(3) Tighten the damper retaining bolt to 108 Nm (80 ft. lbs.) torque.
(4) Install the serpentine drive belt. (Refer to Group 7, Cooling Systems for the proper specifications and procedures).
(5) Connect negative cable to battery.

April 24th, 2012, 21:27
cool, thanks. i am surprised they say to tap on the balancer. i used an installation tool on mine. slid on nicely.

April 25th, 2012, 07:57
Don't tap on the balancer. You can't exactly tap it on any how. You would really have to hammer it on. Its a good way to destroy the thrust bearing.

As for as getting the bolt off you need a way to steady the crank if you are using a wrench. Perhaps inserting a screw driver between the flex plate teeth and the transmission might work, but it may require two people. If you have a manual transmission you can chock the wheels and put it into a gear. At any rate you need more than a standard length 3/8" ratchet. A breaker bar works well.

As a last resort you can use the started to break it free. Rest the breaker bar on the steering box and then just blip the key enough to pop over the starter. However, this can be dangerous and only used as a last resort.

April 25th, 2012, 08:15
he says the engine is out of the jeep and sitting on the ground. that is why i suggested a long wrench and hit it with a hammer. works every time for me. if he has a helper, i bar/pipe/whatever can be inserted through the flex plate and held againt a lip on the back of the block. but if the engine is just resting there, he will have to make sure the engine doesnt tilt over while applying pressure to the wrench. i like the smack technique because it puts a good shock load on the bolt somewhat like an impact driver does.

April 25th, 2012, 08:30
Imma go give it a whirl. Im just surprise theres no special tool for this, I google it and I see almost every other car manufacturer has some sort of tool available for this.

April 25th, 2012, 08:41
actually there is a tool. looks like a triangle with a hole in the center, and three holes to bolt to the balancer. there is also a long handle welded to the triangle piece. once you boltd it to the balancer, you can now hold it steady while using a breaker bar and socket on the center bolt.

April 25th, 2012, 09:07
I just removed mine Sunday. The quickest and easiest way was I removed my drive belt, then put a breaker bar with a socket on the bolt, rested the breaker bar against the pulley to the upper right and cranked the motor...that broke the bolt loose immediately and I could then remove it the rest of the way by hand.

April 25th, 2012, 09:10
And when I say "cranked the motor" I don't mean I held it for seconds...just a quick "blip" as mentioned above. Just enough to turn the crank shaft very instantaneously.

April 25th, 2012, 09:36
if you are going to try the "crank with the starter trick" make sure you disconnect the coil wire. bad things can happen.
again, this will not work for the OP as his engine is sitting on the ground.

April 25th, 2012, 09:46
My apologies...I did not see that the engine isn't in the vehicle.

April 25th, 2012, 13:09
Got it off, my handy dandy impact really worked for once. It cant break a lugnut loose but it spun this sucker right off.

thanks guys, not i just gotta get this damn balancer off

April 25th, 2012, 13:15
Rent a balancer puller at advance auto or auto zone.

April 25th, 2012, 13:28
I've also threaded throwaway bolts into the spots machined for the puller. Then I stood on a long pry bar in between the bolts to hold the balancer in place while pulling on a breaker bar to loosen the bolt.

EDIT: Nevermind, missed that he got it off.

April 25th, 2012, 14:04
Rent a balancer puller at advance auto or auto zone.

theres only a napa here in town. they want 18$ for it, I have one over at my parents house that i left there 30 miles away, ill prolly just wait til I make it over there to get it. dont feel like blowing 18$ since i dont really need it.

April 25th, 2012, 15:12
you can sometimes get away with a 3 jaw puller as long as you can get a grab on the inside hub section. DO NOT pull from the outside edge. a true balancer puller is best.

April 25th, 2012, 15:21
I use the "ghetto impact method" described by 2stix most of the time instead of waiting for my compressor to fill, and hauling out the impact.

I find using a rubber mallet works better than a metal hammer. Big head so you can't miss, you won't marr up your tools, and the rebound of the rubber seems to help as well.

OP: is the flywheel/flexplate still installed?

Edit: too slow

April 25th, 2012, 16:58
No flexplate installed yet, but I do have it in a box. Just saying haha.

I tried hammering off that damn harmonic balancer, I dont need it anyways. but it wont budge. I just want to get on to rebuilding this motor.

I pulled the mains, and rod bearings and I only found one slightly scored rod bearing. Besides that the motor is very gunky. Think I will just get the block cleaned. and replace all the bearings

April 26th, 2012, 06:17
If you do rent a puller try to get one that threads into your harmonic balancer vs one that works like a gear puller. Just easier to work with and you don't have to worry about one of the legs slipping off because you don't have it set right.

April 26th, 2012, 09:48
Neighbor borrowed me one yesterday, Glad I had my impact.

I have a 12 gallon tank and it took 5 full fills of air before that balancer came off. By hand it would have been damn near impossible lol

April 26th, 2012, 09:49
Its all apart. Cranks is mint. Found one rod bearing that was questionable and 2-3 pistons had some marking on them.

But the block has nice cylinder walls. just gotta get it cleaned and prolly go 2 or 3 over to be safe

April 26th, 2012, 09:55
i just replaced the rear main seal and got to look at the rear main bearing and was totally amazed how little wear there was on a 230K+ engine. i think these things can live forever.

April 26th, 2012, 10:02
Yup everything looked nice.

I got a line on some 258 rods and crank so hopefully I can get those soon