Crank Seal Replacement

MP94SC

Registered User
I am replacing the crank seal on my 94 SC while I have the front of the motor apart I plan on replacing the water pump, timing chain, motor mounts, belts and tensioner pulleys. Is there anything else I should do while its apart, such as the oil pump and HB? Thanks, Jon
 
Why are you changing the timing chain?

Once you pull the dampener, it's a gamble whether it will last when you put it back on. So, I would say to replace it.

Also, get the radiator cleaned and checked.
Aaron
 
Since you're already in there you might as well replace the oil pump. It is not necessary to replace the HB, but you definitely need to replace the crank Bolt! While you're at it might want to check out the motor mounts and replace them if needed since you're so close already.
 
go with ARP bolt + Washer

i called jegs and they said they have a ARP bolt and washer for the HB i think its like 14.95...Alex LaChance
 
No need to replace the HB? Replacing crank bolt should be good.
This is certainly a less costly route, is it predestined that the HB will eventually fail or am I safe in assuming that it will operate properly. This particular SC is being kept completely stock with no mods what so ever the other SC has enough for both.
 
...

definetly change the bolt and washer, i believe thats the main problem on the HB, not the acutal HB itself, my bolt snapped and the weird part was my balancer didnt fall out (it was in 2 pieces), but my rpms where jumping around every now on the highway that night on the way home of me driving and then on the highway, i kept driving home on the higway to my house, next day my brother (my mechanic) this all was a couple yrs back, he looked at my balancer and the belt and said WTF ? he pulled on it, and it came right out with his hands HB broke 2 pieces, 1 piece was still left inside and i guess the bolt head was gone with washer, then used an easy out on the bolt out of the crank and it came right out...so i bought a new HB from ford and also a bolt and washer...i will upgrade to a ARP bolt + washer when i get the jackshaft pulley and BHJ balancer later on.(when i have extra funds). to me the ARP bolt + washer is the Fix for the HB failure Alex LaChance
 
Went to the jegs on line catalog and found the arp bolts but didn't see the SC specific bolts. Thanks, Jon
 
...

its i believe a universal part, i'd call there tech suport if you want, its just like the arp flywheel bolts there made for chevy/ford (another good thing to get, i will next time my tranny is down..)...
 
Thanks I'll call tomorrow, if anyone else has any thoughts on HB replacement please post your opinion. Jon
 
I replaced my timing chain at 100,000 miles while I was doing motor mounts last year. I just had to replace the dampener because the dampener broke at the sleeve. I also had to remove the timing cover to get a puller on the crank gear to remove what was left of the old dampener.

So in my case I caused my own problems trying to be proactive on maintenance. Factory dampeners are aluminum and steel and can't handle a removal and reuse.

Buy a new dampener and a 98 Mustang crank bolt if doing a timing chain. Also, pick up a new chain tensioner at Ford they are real cheap.

You have been warned.

Jerry
 
jasonLmarsh said:
Since you're already in there you might as well replace the oil pump. It is not necessary to replace the HB, but you definitely need to replace the crank Bolt! While you're at it might want to check out the motor mounts and replace them if needed since you're so close already.

I agree with doing the motor mounts - he will have both accessory brackets off making it an easy job.

I do not agree with not replacing the dampener. The bolt is not the critical failure point, the dampener hub is. The root problem is the aluminum/steel hybrid hub, it does not have the fatigue resistance neccessary for multiple installations.Please explain your position on why the dampener need not be replaced when the body of knowledge here says it should.

Aaron
 
Aaron,

I tend to agree with you I will probably replace the HB and crank bolt, I have to remove the timing cover to replace the cover gasket. I see that you can buy a rebuild kit for the oil pump for approximately $25.00 or replace the oil pump and cover assembly for $110.00 has anyone had a problem with the rebuilds.

Thanks, Jon
 
Yes, I definitely would replace the HB if you plan on keeping it for long. Some have gotten away with reusing one, but most fail within 10k miles after reinstallation. The stock hubs are cast aluminum that galls badly when installed. So, when it's removed and reinstalled it really isn't an interference fit like it should be. The bolt is absolutely NOT the problem. All the bolt should do is keep the damper from sliding of the crank, not be responsible for holding it on. GM LT1 motors (Z28, Firebird, 'Vette) didn't even use keyways. It was all from the super tight press fit that held them in place.

If you can afford it, get a BHJ steel HB. A couple years ago I had them make a steel damper for us. When they evaluated the 3 test units I sent in (2 early models and 1 94-95 model) they couldn't believe Ford used such a POS on a blown motor. Also, the used balancers measure a .005"-.007" CLEARANCE fit where .001"-.0015" INTERFERENCE fit is recommended. The steel damper is more expensive, but it won't break and can be reused without issue. I believe SuperCoupe Performance stocks the balancers for around $350-$400. A new bolt isn't a bad idea, but I've reused mine 4 times now. Just make sure the crank threads are clean and bolt threads are ok. The bolt only fails after the damper weakens and starts moving around.
 
Thanks everybody for the advice, I ordered a new dampner, 98 Mustang crank bolt/washer, and a timing chain tensioner. This is in addition to the timing chain, motor/trans mounts, water pump, tensioner pulleys, hoses, gator back belts and all necessary seals and gaskets. Still have to decide on the oil pump assembly rebuild or new. Jon
 
pastera said:
I agree with doing the motor mounts - he will have both accessory brackets off making it an easy job.

I do not agree with not replacing the dampener. The bolt is not the critical failure point, the dampener hub is. The root problem is the aluminum/steel hybrid hub, it does not have the fatigue resistance neccessary for multiple installations.Please explain your position on why the dampener need not be replaced when the body of knowledge here says it should.

Aaron

Aaron, I tend to trust my own personal experience over the "Body of Knowledge" knowing that most of that body consist of people speculating about problems based on what they've heard or read on the internet. I think Jon is wasting his money on a new dampener but if he has it to waste... then I envy him :)

The dampener failure is not related to removal/installation of the dampeners (when done correctly) Dampeners tend to fail after having a wobbling bout with broken crank bolts. When the bolt breaks and the car is still driven, the wobbling of the dampener is the biggest cause of the problems. (this was not the case in Jon's post) I'm sure in some areas, rust can also be a major contributor to that failure. I personally have removed/reinstalled dampeners on 3 of my own SC's, Two other SC's and seen it done on another one. NONE of those SC's have had a HB break due to removal/reinstallation. My 93 went another 40k miles after having the HB removed several times. Sold that car. Then my 94 has gone 14k since the motor rebuild with no problems. The 35th anniv bird went 15k before it was sold, and I still see it on the road.
 
to jasonLmarsh

jasonLmarsh

I respect your thoughts a lot on this board. I even have 95 Mustang headers becasue of you. On this I have to disagree because of my own personal experience with two SCs one a 90 and the other a 89.

If the original bolt is reused and torqued at the recommended 109-132 ft. lbs it might fail. I don't think that bolt is rated for that much torque. I had the orignal bolt snap off that happen with my nephews 90 SC. I think a bad crank sensor may have caused the damage due to the violent cutting out of ignition while trying to drive the car home. Either way I replaced the HB and crank bolt along with a new crank sensor and never had any more trouble.

Last year I changed my 100,000 mile timing chain and reused my stock balancer. I used a good HB puller tool and the balancer came off with no problems. I bought a longer bolt to help install the balancer and it went on with no issues. I also bought the 98 bolt and washer and used that. The problem is the dampener broke in 1 year and 6000 miles. The 98 Mustang bolt survived and kept the balancer on, although it had rotated about 15 degrees causing a retarding of timing. I had to basically do the removal of the timing cover twice in two years because of not replacing the balancer. It was not worth the $250 for the new balancer vs my time and loss of vehicle.
 
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