leaking gear box cover

David Anderson · March 26, 2022, 02:51:09 PM

There is a small cover on my drop box leaking oil, making a mess. I pulled it off and there are three steel shims with no gaskets. The bolts were really tight. The book shows no gaskets. Could I use Permatex between the shims, case and cover and seal this up? Seems like an easy solution.

I tried to send pictures but I keep getting an error,
"Path cannot be empty"

Thanks,
David

chessie4905 · March 26, 2022, 03:26:41 PM

Use a straight edge on cover to see if warped.

Dave5Cs · March 26, 2022, 05:12:02 PM

Check vent on top to make sure it is not plugged up.

luvrbus · March 27, 2022, 05:56:57 AM

Time for drop box rebuild David they get to much clearance from bearing wear and leak,check for crush washers they don't use lock washers on those bolts or they leak too,don't use a RTV gasket maker of any type,you preload the bearing and a sealant throws the clearance off.That is a combined lubrication of the box and rear gear check for shaving by draining your rear gear

David Anderson · March 29, 2022, 04:46:06 PM

Here are the pictures. It's leaking out of part number 19. There are 3 shims in there, no gasket.

I called Luke and he said they leak often. They spray a light coat of gasket sealer on the parts to stop it. I ordered some. It's on the way.

He said the shims are no longer available. I better handle with care.

David

tr206 · March 29, 2022, 08:08:25 PM

Dave you can buy shim stock if needed and make your own don't sweat it.

chessie4905 · March 30, 2022, 04:33:33 AM

Run a good flat file across it to remove high spots if any.

luvrbus · March 31, 2022, 08:08:10 AM

David let me know how thick your shim pack is I have new and used shim packs ,you can set the preload with shims on the inter bearing race too,I don't see any shims on the race in your photos but they don't leak if set up right

David Anderson · March 31, 2022, 10:30:02 AM

Quote from: luvrbus on March 31, 2022, 08:08:10 AM
David let me know how thick your shim pack is I have new and used shim packs ,you can set the preload with shims on the inter bearing race too,I don't see any shims on the race in your photos but they don't leak if set up right

The 3 shims are in the picture with the cover. I thought they matched item 20 in the shop manual picture for the shims, .003, .002, .010

Luke says they nearly always leak.

David

luvrbus · March 31, 2022, 11:57:51 AM

Quote from: David Anderson on March 31, 2022, 10:30:02 AM
The 3 shims are in the picture with the cover. I thought they matched item 20 in the shop manual picture for the shims, .003, .002, .010

Luke says they nearly always leak.

David

Maybe Lukes do leak I couldn't answer that

David Anderson · March 31, 2022, 02:28:25 PM

It seems odd to me that there are 3 shims in there. The book lists 3 different thicknesses on item 20, but all three at once?

Seems wonky to me. I don't know enough about these to make a qualified judgement.

David

chessie4905 · March 31, 2022, 04:10:46 PM

Whatever it takes to set endplay to specs. Those are the choice of thickness. Between those three sizes you can get it wher it should be. Too much end play results in shaft banging against cover increasing the likelihood of leaks. Be sure to use sealant on bolts and torque to specs. Grade 8 wouldn't hurt.

David Anderson · April 02, 2022, 12:42:14 PM

I began to clean the shims and there are five shims, each shim (see picture) is .010 +/-. I measured the best I could with my micrometer and the 5 shims came to .049 (see picture) Makes it easy for a leak to happen doesn't it?

I pulled out the dropbox assembly instructions and reread them. The section on the setting this bearing assembly is attached with the picture below. (between the pencils) I am not clear on how to set the endplay on this bearing. It appears it needs to be done with the shims and cover in place which means the big cover (#33 in the assembly breakdown) has to be removed to do this.

I can grab the big nut on the idler assembly and move that in and out by hand (picture with my hand on the nut). I remember that now because I changed these bearings in 2009 and Clifford walked me through that process on the forum. https://www.busconversionmagazine.com/forum/index.php?topic=11625.15
That was 13 years ago. Those bearings were easy to install as I remember. Honestly, I cannot remember setting endplay 13 years ago, because I don't remember removing the cover plate #19 in the diagram. My leak in 2009 was at the big cover #33 which is what was removed at that time, bearings replaced, and new seal installed. It's not leaking there now.

I'm hoping I can spray a light coat of sealer on the shims and cover and bolt it down. If it holds, great. If it leaks, bummer. It's been leaking for several years. I was hoping for an easy repair.

I placed the #19 cover over the bolt holes without the shims and held it by hand. I tried to slip a 1/16" (.0625") drill bit between the cover and the drop box housing. It wouldn't slip through, so the 5 shims are the right thickness to keep the #25 shaft riding just next to the #19 cover for the needed gear lash.

Am I describing all this correctly?

David

David Anderson · April 02, 2022, 12:47:04 PM

Another copy of the parts diagram

David Anderson · April 04, 2022, 09:22:23 AM

The manual is not clear on how to set endplay. I can install the cover over the shaft without the shims and push the shaft in until the cover is snug to the case. Then I can remove the cover, lightly tap the shaft and pull it back.

My question is how do you set the endplay on this? It just says, "set endplay on bearing." This instruction is after both covers #19 and #30 are installed.

Nobody will work on these boxes anymore. I'm on my own here. Luke snickered when I asked him questions about it.

Anyone with experience with these, please chime in.

David