Motobecane AV7 crankcase bearing and oil seal removal.

Christopher Manning /

I am trying to rebuild this AV7 and I need to replace the crankshaft brearings and crank case oil seals. Whats the best way to do this? I found this tool (https://www.1977mopeds.com/Motobecane-Crank-Bearing-Puller-p/3157.htm) but its out of stock and I would rather get a universal bearing removal kit. Any suggestions for what kind of kit I should get? As far as removing the bearings go, I have read about people heating the crank case in the oven and popping the bearings out. Is this an alright method or should I shoot for getting a universal bearing removal kit?

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Re: Motobecane AV7 crankcase bearing and oil seal removal.

Heat up the cases then use a socket and a press or a mallet to tap them out. Heating the cases also helps with installing the new seal too. Its pretty easy to botch it your first time so be careful.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

Christopher Manning /

So use a socket that doesn't fit through the bearing to tap it out from the other side? I just tried heating up in the oven at 325 convention bake for an hour. I had no luck getting it out.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

Blind hole puller.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

> Christopher Manning Wrote:

> -------------------------------------------------------

> So use a socket that doesn't fit through the bearing to tap it out from

> the other side? I just tried heating up in the oven at 325 convention

> bake for an hour. I had no luck getting it out.

Maybe because you didn't have the temp high enough .

I use a small propane grill . Crank the heat to 400° , put the case in . Remove the case about 15 minutes later .

Bearings fall out with the slightest touch .

If you're quick enough , the new bearings pretty much fall into place , as well .

New seals go into place while the case is still very warm to the touch .

Re: Motobecane AV7 crankcase bearing and oil seal removal.

What Stephen said. I've had to use a blind-hole puller bit as a "surface" and a regular puller to "push" the bearing out (I wish I'd taken pics of the "rig"). Make sure you get the cases really hot. and support on a wooden surface (a 2x4 in a vise with a hole big enough for just the bearing to come through when it comes free) so you don't damage the case surfaces.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

Dirty30 Dillon /

Heat

Blindhole puller

Slide hammer attachment

Thick ass glove

Re: Motobecane AV7 crankcase bearing and oil seal removal.

I rebuilt mine earlier this year. The MB factory service manual I was using called for a propane torch to heat the case. I used a heat gun, and a temp gun. Everything started coming loose around <Edit> 220C (like ~400F on the grill above degrees), basically until everything just started to smoke. One side fell out while I was heating it, the other dropped when I tapped it on the work bench. Assembly is reverse. I did cool new new bearings in the freezer for a couple of hours and put some assembly lube on the bearing before I started heating the case. You can seat with a socket that mates the outer surface of the bearing. Yes, do wear gloves.

This guys explains it well:

The seals aren't hard to get out. Just don't mar/gouge the seating surface on the case or the crank hole. You can grab 'em with some needle nose pliers and give 'em a good tug. Clean the case well afterwards, there will probably be some old gunky seal material left behind on and case.

As far as new seals... IIRC, I ended up using these, based on a post elsewhere:

https://www.avxseals.com/Shaft-Oil-Seals-TC15x21x4-p/tc15x21x4.htmEdited 3 time(s). Last edit at 12/23/18 08:58AM by d3r3zz3d.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

mike thompson /

There is this guy on youtube that has done a whole mulit part video series on Moby teardown and rebuilds. They are excellent. He shows exactly how he did what you are asking. Each segment is called "david fixes his shit" but don't use that as a search. Actually, here is a link to one of them (I don't think what you need is in this specific one though. I think it may be in the one before this one)

Re: Motobecane AV7 crankcase bearing and oil seal removal.

That dude is fun to watch. I watched his whole rebuild series before I started on mine. Revisited a couple of times when I had gotten myself totally confused.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

rebel moby puts dave to shame...ie; cigarette carton base gasket.brake pad mod.etc,etc,etc.

dave is a good, because u see his mistakes & can learn from them.

Re: Motobecane AV7 crankcase bearing and oil seal removal.

Shave the cases so you can install the seals after the cases are assembled. It's so awesome.

I despise not being able to install or pull seals from outside the cases

Re: Motobecane AV7 crankcase bearing and oil seal removal.

200* on the aluminum carters

crank wrapped up in the freezer

...dirty30 thick ass gloves

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