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85jeep 09-11-2005 02:45 AM

amc 20 cover gasket
Does anyone know where I can Find a rubber gasket for a amc 20 rear end. I seem to get water in it alot and its a pain to dump the fuid. They shoud have drains on the diffs like they used to on the old trucks. I thought I saw one advertised once but now can't find it.

Jim_Lou 09-11-2005 06:38 AM

Re: amc 20 cover gasket
Next time you have the cover off drill and tap a hole in the bottom of the housing, and then clean the chips out. Stick an allen-head pipe plug in and you'll have your drain.

You'll probably have to make a rubber gasket. A parts house should have sheets of rubber gasket material. Just use a paper gasket as a template. Cut it carefully with a razor blade, and make the bolt holes with a paper punch.

You should also find out how water is getting into the housing. Is the vent line sound and run up high somewhere? I tied all the case vents into a hose inside the frame rail and ran it up to the air cleaner housing.

JimmyZ 09-11-2005 06:59 AM

Re: amc 20 cover gasket
Um...., sorry.... an Amc model 20 cover gasket has no bolt holes. It's just a flimsy ass thin cork thing. See if you can compare different gaskets. Some are thicker. Clean both surfaces, housing and cover thoroughly, then clean them again. Then I used Permatex Hi Tack(sp?). It's red and will make the gasket stick in its place while you get some bolts started. It's also kind of anal but see if you can draw the cover bolts in evenly to get the gasket to compress evenly.

pontiac58 09-11-2005 07:08 AM

Re: amc 20 cover gasket
i doubt the water is coming in from the gasket, like jim lou said, find where the water is coming in from.

If you want a drain, drill the housing, tap for 1/4 pipe and use a pipe plug. Again like Jimlou said. I do that to all my rears and any 9in i build for our customers.

For the cover gasket, just use silocone, put on a nice heavy bead, cause you have to fill that ring and smoosh the cover on, let it sit overnight and refill the next day.

mach2_nh 09-11-2005 08:16 AM

Re: amc 20 cover gasket
Just user RTV for it. works good.

Jim_Lou 09-11-2005 11:09 AM

Re: amc 20 cover gasket
Um...., sorry.... an Amc model 20 cover gasket has no bolt holes.

[/ QUOTE ]

Generic instructions, not always applicable to specific situations.

jdoggmoney 09-11-2005 11:32 AM

Re: amc 20 cover gasket
For my dif drains, I drilled a hole then welded a jamb nut to the inside of the cover (as low as possible) and use a 7/16 fine tread bolt with a gasket to seal things up. [img]/ubbthreads/images/graemlins/grin.gif[/img]

**DONOTDELETE** 09-11-2005 05:37 PM

Re: amc 20 cover gasket
Fix your water problem and you won't need to keep draining it.

Two areas to check....the obvious is the vent line near the right spring.

A commonly ignored spot is where your brake line Tee attaches to the axle tube. If this bolt gets loose, you will get water in the housing. Make sure it is tight...better yet, pull it off and put some RTV under it before you put it back on.

Also make sure your not getting water in through the axle tube to pumpkin area. It won't hurt anything to run a bead of RTV around the seam...they only weld it in 3 or 4 places. (ok, that's 3 areas)

85jeep 09-11-2005 05:49 PM

Re: amc 20 cover gasket
OK I just put in new rear wheel bearings and new inner and outer oil seals so I hope this fixes the problem of water comming in. My vent tube is good and high. I mesured the case last time I had it apart and it didn't seem thick enough to drill and tap. I have a friend with a tig welder and he offered to put a drain hole on the bottom of the cover. I think I might do that. I know it wasn't leaking threw the cover but with a rubber reusable gasket It would save the drying time on the rtv silicone. I didn't relize the bolt on the brake went threw the tube I will stick a little silicon on there as well.. If any one has had this apart they will see a weep hole on the outer axel seal that goes out the back of the brake plate. I guess it is to let any leaking fluid out and off the brakes But it also gives water a straight path to the outer seal should there be a plug in it or some thing. I filled the area outside the seal with grease as well.

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