Replacing seal behind harmonic balancer?

EmpirE231

EmpirE231

Well-known member
Joined
Aug 12, 2021
Messages
531
Reaction score
438
Is it called the crank shaft seal or front main seal? Either way, it’s gotta be replaced. What do I need to pull that seal? 
 

also heard to replace the bolt at the same time? Anyone done this before and can offer some tips?

 
I have a balancer puller. Seal is easy with a seal puller tool. Always a good idea to not reuse the pulley bolt. But I have reused them and had no issues.

 
L.R.S. said:
I have a balancer puller. Seal is easy with a seal puller tool. Always a good idea to not reuse the pulley bolt. But I have reused them and had no issues.
Click to expand...
Do you usually just use a big ass impact to pull the bolt off, and reinstall the bolt? Or torque to a certain spec? 

 
Impact gun will work but best practice is to lock the flywheel and use a breaker bar to loosen the bolt. Factory bolt should be replaced but using an ARP bolt is the way to go. ARP bolt is torque to spec and factory bolt you torque and then go another 140 degrees. Front seal pushes out of front cover easily and installs the same (assuming you are removing the cover) Care should be taken when reinstalling the cover to ensure the seal is centered on the crank. There is a tool for this but it can be done without it if you are careful. Might want to think about oil pump, timing chain and tensioner while you are in there. 

 
Sandkist said:
Impact gun will work but best practice is to lock the flywheel and use a breaker bar to loosen the bolt. Factory bolt should be replaced but using an ARP bolt is the way to go. ARP bolt is torque to spec and factory bolt you torque and then go another 140 degrees. Front seal pushes out of front cover easily and installs the same (assuming you are removing the cover) Care should be taken when reinstalling the cover to ensure the seal is centered on the crank. There is a tool for this but it can be done without it if you are careful. Might want to think about oil pump, timing chain and tensioner while you are in there. 
Click to expand...
Does the cover need to come off? I thought the seal can be changed without removing the cover?

 
EmpirE231 said:
Does the cover need to come off? I thought the seal can be changed without removing the cover?
Click to expand...
Not sure if that seal is wide enough to get a hold of with the cover installed. Would definitely be less work that way. Getting the crank pulley off is the hardest part of the job. If you have to pull the cover than the water pump/coolant needs to be removed first. After that, pulling the cover is easy.

 
i had mine push out of the cover on its own and the new one had pushed in easily you should be able to get it done with the cover on. just be careful not to mark up the crank.

 
Sandkist said:
Not sure if that seal is wide enough to get a hold of with the cover installed. Would definitely be less work that way. Getting the crank pulley off is the hardest part of the job. If you have to pull the cover than the water pump/coolant needs to be removed first. After that, pulling the cover is easy.
Click to expand...
You can change the seal without removing the cover - you just carefully pry it out - however every seal is a little different - manufacturing tolerances on cheap parts  ....  and you should use and alignment tool  when installing the seal or you run the possibility of it leaking worse at higher RPM (oil spray).  I would take the cover off if it was me - easier to install the seal correctly with a Flat piece like a  2x4  and light hammer   i use my press to put them in if you one or an arbor press  - that works best.   when you price the GM seal you will find for a few $ more you get a bright new shiny cover along with the seal. thats what I do 99% of the time 

Also most seals just don't leak unless the engine has 100,000 miles or it was  cheap china seal  or more likely their is a groove in the hub of balancer  where the seal rubs from sand getting in there.  If thats the case you need a new balancer or you can a "seal saver"  which is a thin stainless ring that installs "carefully" over the hub .    They also leak when  the front main is going away, but you would see lower oil pressure if that was the case .

Getting balancers off is pretty easy  - getting them back on not so much  - clean the crank snout  and balancer hub really well and use a bit on antiseize or light oil, on the snout and a bit of grease on the seal  where the snout goes as you install the seal  - press it on straight -  which is hard to do with the cover on  - it has to go in straight so use the right size pipe, PVC pipe or Big Ole socket,  tapping with a hammer.   If you get it in crooked while you install it will leak like hell.

To install the balancer, heat the balancer hub with a propane torch to about 180 degrees  - use an IR gun if you have one - it won't hurt the seal because the hub gets that hot in Normal operating temp, and slowly pull it on with a balancer install tool  - you can buy one or rent one  - but it has to be for an LS.  If you don't clean or take your time - you might burr the balancer inside and you will hate life - Like the guys said on bolts, ARP or New GM bolt - good advice stock Bolts are TTY  and Balancers come loose and ruin cranks  and other stuff

 
Last edited by a moderator:
Easy to do. 
Took me 15 minutes. 
Get ARP bolt and use that. 
Autozone has a puller/installer kit. Makes it easy. 
I left my cover on and my crank is pinned. 
Oh yeah. Use grease or anti seize as stated. 

 
Last edited by a moderator:
Had to do one on my truck gm 6.0 wasnt a big deal didnt remove the cover was able to remove and replace the seal.I did end up buying the puller got one on amazon for 30 bucks worked great now it sits with my special gm tools LOL.But know enough with ls engines now so i can loan them the puller if needed

 
So all 3 have failed at breaking the bolt loose…. Any ideas??

IMG_9442.jpeg

 
A 3/4 drive impact will get it off. You may want to invest in a flywheel locker anyways, they are cheap and come in handy when you need to tighten the balancer bolt.

 
Last edited by a moderator:
We do them almost every day, 

The trick is a Big fuel Impact 1/2 fine,  

But you will need to heat them up with a MAP gas torch for about a minute to a minute in a half,  

This does a couple of things, it will expand the bolt a little and if locktite used it will loosen the locktite,  

We have used in the last 15 years - all seals, 

The best is the GM Original equipment seal    it will still go out but last a lot longer,  really depends on the car and how the skid plate the balancer style ect...   

Every seal we take out that is bad has sand in it,  or if you do not have a oil temp gauge, the upper temps will eat them up easier,  

If it is a stock puller then this will work good, 

OEMTools 25090 OEM Automotive Tools Harmonic Balancer Puller Sets | Summit Racing

This style puller will not destroy the threads, the shaft will go deep into the crank  ^^^^^^^

INSTALL 

I do not like to tap the balancer on and hit it with a impact,   I have done a couple hundred seals  and as tempting as it is,  a couple times in the past, the threads gauled and the bolt had to be broke out and drilled then tapped 

Us a cheap good installer, 

Summit Racing SUM-900135 Summit Racing™ Harmonic Balancer Installation Tools for GM LS | Summit Racing

This one works good,  but if you do more than about 50 times the bearing goes out, 

We use a 12point bolt, if you need one PM us we keep them on the shelft,  or PRW, Speedmaster ARP work the same, 

  • Factory bolt new - has locktite and sealant on it - so torque to 250lbs and you are good
  • Reusing a bolt,  make sure to use silicone on the flange so it does not leak,  and locktite on the threads
  • 12PT, use silicone on the under head and on the washer, and locktite on the threads
  • Torque all to 250lbs 
 
KLC said:
A 3/4 drive impact will get it off. You may want to invest in a flywheel locker anyways, they are cheap and come in handy when you need to tighten the balancer bolt.
Click to expand...
Any link to one of these that works with a VW bellhousing / LS setup?

 
You must log in or register to reply here.
Back
Top