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drive train => front and rear differentials => Topic started by: col.halftrack on May 19, 2012, 10:17:02 AM

Title: Replacing rear pinion cork seal
Post by: col.halftrack on May 19, 2012, 10:17:02 AM
 I am getting ready to put a rear axle under the M4A1. The manual says you can pull the pinion assembly by removing the six bolts holding on the pinion seal flange. I removed the flange nut and noticed the keyway has been sheared allowing the flange to slip twenty degrees out of line. A standard two jaw puller with heat added has failed to pull the flange so I am wanting to pull the pinion assembly and try pressing the flange off. Pinion assembly pulled out about one half inch and seems to be held. Before I start prying and beating anyone done this before and have some ideas?
 Thanks
 Kevin
Title: Re: Replacing rear pinion cork seal
Post by: yd328 on May 20, 2012, 07:08:46 PM
Kevin,
It sounds similar to the front axle, I just did mine and the same thing happened. The pinion did not come out, it was hanging up on the ring gear. I have my rear diff out but I will not be able to take a look at it until tuesday.

Gary
Title: Re: Replacing rear pinion cork seal
Post by: yd328 on May 22, 2012, 03:30:40 PM
Kevin,

the pilot bearing looks like it will hit the ring gear when you go to pull out the pinion, thats what happened on my front diff. I was splitting the axle in half so it didn't matter. It looks like you will have to pull the ring gear out first to get the pinion gear out. I can post some pictures if it helps.

Gary
Title: Re: Replacing rear pinion cork seal
Post by: Outsider on May 22, 2012, 06:45:18 PM
Kevin, If I remember correctly there is room to do this. Take a 5 lb sledge and put it on one side of the collar where it slides over the pinion shaft and use a 3lb to hit on the other side working back and forth a little may be the trick you need to get that off. The shaft is tapered so a little work on the sides should get it to break loose.

Steve
Title: Re: Replacing rear pinion cork seal
Post by: steve-0 on May 22, 2012, 07:29:18 PM
i also had 2 of those that sheared the keyway.
one was loose but the other was just about welded in there. i used heat but nothing worked. i had the option of using a different one so its still stuck.
i think if i was going to try pull it again i would do as you mention. pull the whole 3rd member and put it in a press. pullers are to hard on the flange, you will end up bending it.
Title: Re: Replacing rear pinion cork seal
Post by: dwhite on November 30, 2015, 09:31:59 AM
Does anyone have a source for the cork gasket (ORD A214939) and/or the differential carrier gasket (ORD B184319)?  Thanks, DW
Title: Re: Replacing rear pinion cork seal
Post by: Outsider on November 30, 2015, 12:07:02 PM
Do you have a picture of the cork gasket?

The carrier gasket should be available from a heavy truck parts shop. As it is the same carrier as used on some older model trucks.

Steve
Title: Re: Replacing rear pinion cork seal
Post by: dwhite on December 01, 2015, 04:26:01 PM
The rear pinion cork gasket picture in the parts book doesn't have a lot of definition.  Unfortunately the old cork gasket I have ended up in pieces; however, the gasket is around 4.54" OD x 4.145" ID x .400 wide.  Does that ring a bell with anyone?
Title: Re: Replacing rear pinion cork seal
Post by: steve-0 on December 01, 2015, 05:05:04 PM
here is some material.

1/2"
http://www.mcmaster.com/#9487k5/=101zbjw


3/8"
http://www.mcmaster.com/#9487k8/=101zbnc


i don't have the specs on this seal but going by what dwhite posted you may be able to use rubber o ring material.
to make an o ring out of ring material you cut it to length with a razor and super glue the ends together. this is done even in hi pressure systems.

not sure if this is the right size
http://www.mcmaster.com/#9407k17/=101zdg6

or
http://www.mcmaster.com/#1034t5/=101zhjh
Title: Re: Replacing rear pinion cork seal
Post by: Darth_Kitten on December 01, 2015, 09:29:58 PM
I'm pretty sure all the NOS gaskets are dried out just like the valve cover and oil pan gaskets. I received an NOS one a couple months ago, and it was fragile and broke in a couple places. I still ended up using it and just sealed the breaks with RTV.
Hopefully it holds up.
I'm guessing you're better off making a new one if you can...
Title: Re: Replacing rear pinion cork seal
Post by: steve-0 on December 01, 2015, 09:36:25 PM
i may have misread the measurements dwhite listed.  he listed .40 wide and i used that as the thickness.

anyways mcmaster has sheets cheap

here is some 1/8"   I'm not sure what is required.
http://www.mcmaster.com/#9487k3/=1022rsp
Title: Re: Replacing rear pinion cork seal
Post by: steve1973 on December 01, 2015, 10:41:07 PM
I'm pretty sure all the NOS gaskets are dried out just like the valve cover and oil pan gaskets. I received an NOS one a couple months ago, and it was fragile and broke in a couple places. I still ended up using it and just sealed the breaks with RTV.
Hopefully it holds up.
I'm guessing you're better off making a new one if you can...

I have new made valve cover and oil pan gaskets. These are fresh made and ar not NOS if interested. I also have complete engine and transmission gasket sets that are made fresh, not NOS.

I think I had the same problem with my NOS oil pinion seal. It feel apart when installed. I believe the repair shop used some silicone or something instead.

Steve A.
Title: Re: Replacing rear pinion cork seal
Post by: dwhite on December 21, 2015, 04:35:23 PM
I appreciate the input that y'all have provided.  I ended up going with 3/16 square o-ring stock (McMaster #9700K13) and superglue.  It took me a couple of tries, but if you cut the circumference about 1/2" small, glue, and then stretch the o-ring in place you'll end up with a good seal.  Total investment: $4.  DW