Front crank seal? Easy mechanic job?

72c10

72c10

JK Enthusiast
Joined
Jul 8, 2020
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150
Location
Utah
First: I love my mechanic. He's been doing a good job and treating me well as hell for 15yrs. I even consider the proximity of his shop when I look at a future house to buy. He's been around for at least 25 yrs, with another friend going to him for that long. But, he said he hasn't done a front crank seal on a Jeep before.

With that said: I was going to try to tackle it. However, the time to rent or buy a harmonic balancer puller and running into things a first-timer would struggle with and take more time, I figured I'd spin money in the economy with a trusted mechanic.

My front crank seal was ONLY seeping and I wanted to get ahead of it, before I started to do 3-4 hr trips to Moab. Don't want to go far out enough where it started slinging oil.

Dropped off my 07 JKU and a Felpro front crank seal to him this morning. I thought it would take 3-4 hrs at the most. He calls me 6 hrs later and said he messed up the first seal as it turned cockeyed when he tapped it in.

So, he had another one delivered. After he buttoned up the 2nd one, he started it and it started "spurting oil" between the seal and the crankshaft. My first thought - did he scratch the crank when he took the other one off?

He then told me he'd really inspect it tomorrow and get a new seal to figure out what's going on. He hinted at "maybe it's the crank shaft" and my stomach turned to knots from frustration.

My Jeep ran pretty damn good w/o any leaks. The crank shaft seal was seeping a little, never producing a drop of oil on the garage floor.

Now, I'm frustrated as hell.

My initial instinct was he damaged my crank when taking out the old seal.

Maybe he just got a bad seal from the supplier that brought the 2nd one.

He took a 2-3 hr job (if that) and I'm either gonna have to fork out $$$$ for a new crankshaft or just have him put it in leaking and go trade my baby in. I just got it regeared (break-in inspection scheduled for this Friday at the off-road shop) and now I might have to trade it in? F@#*!!!!!!

I hate when people read the internet or watch YouTube videos and tell me how to do my job.... and I don't want to tell him that I've seen YouTube videos and saw on wranglerjkforum.net that first-timers have done this successfully without issues. But, I guess next time I'll take a day off and take my time and do the work myself. I'd rather be frustrated at my Jeep than I would at him (hard to find a fair mechanic).

Now, if I get it without leaking. I'll be checking under there weekly to make sure it doesn't shit, always doubting if he did it right.

Thanks for letting me vent. This is why I love you guys.
 
Last edited:
72c10 said:
First: I love my mechanic. He's been doing a good job and treating me well as hell for 15yrs. I even consider the proximity of his shop when I look at a future house to buy. He's been around for at least 25 yrs, with another friend going to him for that long. But, he said he hasn't done a front crank seal on a Jeep before.

With that said: I was going to try to tackle it. However, the time to rent or buy a harmonic balancer puller and running into things a first-timer would struggle with and take more time, I figured I'd spin money in the economy with a trusted mechanic.

My front crank seal was ONLY seeping and I wanted to get ahead of it, before I started to do 3-4 hr trips to Moab. Don't want to go far out enough where it started slinging oil.

Dropped off my 07 JKU and a Felpro front crank seal to him this morning. I thought it would take 3-4 hrs at the most. He calls me 6 hrs later and said he messed up the first seal as it turned cockeyed when he tapped it in.

So, he had another one delivered. After he buttoned up the 2nd one, he started it and it started "spurting oil" between the seal and the crankshaft. My first thought - did he scratch the crank when he took the other one off?

He then told me he'd really inspect it tomorrow and get a new seal to figure out what's going on. He hinted at "maybe it's the crank shaft" and my stomach turned to knots from frustration.

My Jeep ran pretty damn good w/o any leaks. The crank shaft seal was seeping a little, never producing a drop of oil on the garage floor.

Now, I'm frustrated as hell.

My initial instinct was he damaged my crank when taking out the old seal.

Maybe he just got a bad seal from the supplier that brought the 2nd one.

He took a 2-3 hr job (if that) and I'm either gonna have to fork out $$$$ for a new crankshaft or just have him put it in leaking and go trade my baby in. I just got it regeared (break-in inspection scheduled for this Friday at the off-road shop) and now I might have to trade it in? F@#*!!!!!!

I hate when people read the internet or watch YouTube videos and tell me how to do my job.... and I don't want to tell him that I've seen YouTube videos and saw on wranglerjkforum.net that first-timers have done this successfully without issues. But, I guess next time I'll take a day off and take my time and do the work myself. I'd rather be frustrated at my Jeep than I would at him (hard to find a fair mechanic).

Now, if I get it without leaking. I'll be checking under there weekly to make sure it doesn't shit, always doubting if he did it right.

Thanks for letting me vent. This is why I love you guys.
Click to expand...

Sorry to hear that man. Any updates?

Hard to see how you'd scratch that hard ass crankshaft unless he was using a jackhammer to get that seal out. He probably just left some of the old seal in there/didn't clean it good.

I'm working right now to figure out what I'll need to install the harmonic balancer. According to the part info I found, the bolt is an m10x1.5 thread 60'ish mm long.

Most of the videos I've seen on doing it they reuse the front bolt to push on the new balancer, which is a very, very (can't use too many verys here) bad idea. That's why you also see so many forum posts where that bolt broke off in the crank.

The puller is easy to find, but the installer tool...something else. The miller tool is $150 if you can find one on ebay. I looked at a ton of installer kits and none of them were m10x1.5 Ugh. So I found a place to order some bolts from. I'll order an OEM crank bolt to verify fitment before I ever tackle this. Would suck to get it off and not have something to get it back on with.

Seeing how this is key to doing timing chain as well....I figured I better explore this now.

We all know that gut wrenching feeling. Hope it works out ok.
 
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I own a shop. Id rather guarantee my work on a full engine or transmission swap than a damn seal. Your putting a new seal in an old housing around a worn/ rusted/ whatever metal shaft. Even an axle seal is bad. Id rather guarantee a re-gear than an axle seal. If you put in a ring and pinion and set the lash and mesh... the gear will be fine every time. If you meticulously put in a new seal it may seap from day one.

Now "spurting" is another thing. As far as damaging the crank? Is possible but to hurt a hardened crank you would pretty much have to take a chisel and hammer to it. No seal remover or pick could do it. It's possible but ive never seen it happen. Most likely IF the crank got hurt it happened getting the balancer off. They are stuck on there lol. So much in fact that they don't slip on the crank WITHOUT a key.

No shop has ever had 100% success on seals unless they did only one and got lucky and never took another seal job. Lol. A neighbor had his Ferrari engine pulled 2x for the same seal under warranty. The factory seal was damp. The next seal seaped. The third time it stayed dry. That was at a Ferrari dealer 3 hours from his home charging 200 an hour

I've never seen a factory bolt broke off in a crank. Maybe a cheap grade 3 tractor supply bolt but not a good bolt. Ive seen several hundred put in with the bolt. Usually silicone or grease and then use the bolt. I have several different installers. They work 3/4 of the time.
 
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Creston said:
I own a shop. Id rather guarantee my work on a full engine or transmission swap than a damn seal. Your putting a new seal in an old housing around a worn/ rusted/ whatever metal shaft. Even an axle seal is bad. Id rather guarantee a re-gear than an axle seal. If you put in a ring and pinion and set the lash and mesh... the gear will be fine every time. If you meticulously put in a new seal it may seap from day one.

Now "spurting" is another thing. As far as damaging the crank? Is possible but to hurt a hardened crank you would pretty much have to take a chisel and hammer to it. No seal remover or pick could do it. It's possible but ive never seen it happen. Most likely IF the crank got hurt it happened getting the balancer off. They are stuck on there lol. So much in fact that they don't slip on the crank WITHOUT a key.

No shop has ever had 100% success on seals unless they did only one and got lucky and never took another seal job. Lol. A neighbor had his Ferrari engine pulled 2x for the same seal under warranty. The factory seal was damp. The next seal seaped. The third time it stayed dry. That was at a Ferrari dealer 3 hours from his home charging 200 an hour

I've never seen a factory bolt broke off in a crank. Maybe a cheap grade 3 tractor supply bolt but not a good bolt. Ive seen several hundred put in with the bolt. Usually silicone or grease and then use the bolt. I have several different installers. They work 3/4 of the time.
Click to expand...

The crank bolt torque rating is 40 ft lbs. Not sure what that bolt is rated at, but there are a lot of examples I came across looking into it.

In one case, a guy JB welded the head of a bolt on and managed to get it out and you can see how distorted it is from over torque.

Just not worth the risk, imho.
 
@Cresron: Thanks for the insight. Damn seals!

@Vman: he had a bolt with washers to press the balancer onto the shaft. Just get it done at the dealer. The local Jeep dealer would've done it for $160. Id just rather pay my small business mechanic. He just stresses me out at times, but he's a good dude.

@BLACKJKU: there's about a 1/4" gap between the back of the balancer and the seal. Part of the shaft is exposed. He said there was A LOT OF SAND in there and mother effed the engineers at Chrysler for that design and not having anything to protect the seal.

Update: Fixed. Brought it in today, he actually had me help him with the little stuff like taking the belt off and moving the track bar to give him room.

Upon looking at the seal with the harmonic balancer off, we saw a rip in the seal. He said that he must've ripped it putting it in when he tried to do it from the ground on his back, instead of hoisting up the rig.

Well, with it on the hoist this time : the view for the view install was spot on (opposed to doing it from up top, because he's vertically challenged and I have a bumper with a stinger.

He put the new one in there carefully and it IS NOW BONE DRY! He felt so bad that he scared me about the crankshaft and taking so long, he didn't want to charge me for the labor. He got paid anyway.

So, lesson learned and it's been in a few instructions: put it in delicately.
 
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