Can pull cam drive bearing in all the way.

I’m having a problem replacing the cam drive bearings on my 1975 GT4. It’s the old design with the external seal.
I tried to pull the bearing in with the gland nut, first with an oversized washer (first picture) and then with a 2" washer that catches both the inner and outer race (second picture.) It went in as far as the last picture and won't go an further. I tried a little extra persuasion with a breaker bar, and the Superperformance hex nut started to strip. You an see the threads on the drive shaft are gettng pretty shiny, even though I greased everything.

I made sure the bearing spacer wasn't tangled up in the inner circlip by putting a little grease on it to "glue it the right spot. I suppose it could have slipped and interfered with the bearing.

Next step is to destroy this new bearing pulling it out and check everything. I put motor oil on the bore and the shaft, anything else I should know? Heat the bearing or apply different lubrication?

Thanks Gregg

( Rest of my rebuild thread is at http://www.ferrarichat.com/forum/showthread.php?t=343014&page=3 )
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Gregg,

Poor a whole bunch of Boiling water on it,,, the aluminum will expand more then the steel.
Good thing you are at sea level.
Good Luck.

Edwardo

 

Not sure hot water will do it, you might need more energy than that. Think it through before you ratchet up the violence. Are you certain it isn't bottomed against something?

I've used liquid nitrogen for this kind of job (on the bearing before it goes in) but it's not always easy to find.

 

one thing too is that the gear is not fixed and as such may have floated towards the front case which means you could be fully seated to the gear and thus need to move the bearing and gear in order to get the clearance to install the c-clip.

When I redo these it's with the cover and engine disassembled so the bearings are in before the gear, the gear is then pressed into place. doing it in-situ and by using the gear to pull the bearing in can result in this type of situation.

 

Perhaps a gentle tap to see if the bearing moves back?

I was thinking of placing one of the washers that fits in the bearing bore onthe bearing, and then use a piece of pvc pipe longer than the drive snout to take the blow from a small machinists hammer. That way the gear could rotate freely, and the bearing would take the impact on inner and outer races. Measure the current depth, tap, measure to see if it moves?

Does that make sense?

 

How about using a pvc pipe that just fits inside the bore, and taping that to drive the bearing back? The gear is floating, so applying force to the inner race is a waste/bad idea.

Am I on the right track?

Thanks, Gregg

 

let 'er rip.

 

Oh oh,

Liqhid Nitrogen can be on hand at any Water Lab,,, bring your own Dewer.
But the water works.

Aluminum has a Very high rate of heat transfer.
That whole front cover will be 212 deg F before the bearing is even warm.
( Oh BTW,,, I have done this on other Ferrari Aluminum to Steel bearing slip-fit parts for install.) But, (whew) Nope, don't want the reliability.
winky, winky,


BTW, Cryo-treating a 440 Chrome steel,,, with out control can't be good......?
Oh, and if you pull that old style front cover, you might want to replace it with a later style w/ internal seal type.

Edwardo
Good luck,
I have an entire bearing set,,, from Italy, up for grabs, fits both style Ferrari 308 Front covers.

 

I had only pressed in the rear drive so I compared the two. Sure enough the shaft with the new bearing extended from the case the same amount as I could pull the front drive forward. So I measured the depth of the bearing in the case and gave it a tiny little tap on the special tool shown in the first picture. (It's made from a gray PVC electrical coupling sanded down a little and gray-taped to a big socket.

It moved .010. So I measued the depth of the land for the circlip and wacked it until I went a little past. I figure I can install the clip and pull it back with spacers. All at room temp. Or garage temp, about 52.

I'm stalled now because I'm cheap. Next lesson learned: Don't buy cheap circlip pliers.

Anyway, thanks for saving me a ton of time and expense. I'll write it up step by step on the rebuild thread.
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From this last picture it seems like you did it with the engine in place. Is that correct?
If so, how hard is it to do it in place? I know it is no big deal with the engine out.
Great work, by the the way!

P.S: One good technic is to put the bearing in the freezer before installing. I do it all the time

 

A question here. If you have the early style bearing with seals can you install the newer bearing with integrated shields/seals. If so why would you want to install the old style assembly.

 

You need to replace the cover to do that ...

 

Because, even if you could use the later (sealed) outer bearing in the old design (and I don't think that you can because it is physically wider, as RGigante noted, to accommodate the seals), it would do nothing to reduce the bearing loading and gives a small penalty in lubrication (the open oil bath of the old design is better for lubrication than the grease in the new design).

See post #4 in this thread:

http://www.ferrarichat.com/forum/showthread.php?t=338731

for an explanation of why relocating the outer bearing in the later design significantly reduces the bearing loads (so it's worth accepting the small penalty in lubrication).

 

OK , I got it and thanks.

 

For RGigante, it's not to difficult to get access withthe aircon swung out of the way. The tool from T&E or Draper makes pulling the bearing easy. I would suggest buying a spare ringnut since you run it in and out of the threads 20 times pulling the bearings in.

I'll wait to hear the engine run before I decide how easy it is. Cheers, Gregg

 

Steve another quick question. Is it possible that the seal could be leaking (because of age) without the bearing being bad? If so how would you verify if the bearing was good if you see no run out of the pulley. Would you just replace the front seal? Just asking, thanks.

 

I guess that's another advantage for the later design because you wouldn't have this option of only replacing the seal

Minimal runout of the belt drive sprocket is certainly a good sign for the outer bearing, but bearing failure is usually fatigue related (cumulative# of cycles) so if it was a case of having just recently replaced the outer bearing and seal, but the seal started leaking after ~10K miles (and the runout seemed low), I'd just replace the seal. On the other hand, if the outer bearing had ~60K miles on it, and had never been replaced since birth, I'd say it could be replaced without regret. Once you get the seal out, you might be able to do a visual inspection of the raceways and balls to help make a decision if you are somewhere inbetween those cases. JMO.

 

Thanks again , good info

 

Thanks for the info. I'm familiar with the puller, I've used it before. I've used it with the engine out but was curious to know how hard it would be to do it with the engine in place. Thanks!