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Topic Summary

Posted by: Matto
« on: June 26, 2011, 09:29:52 AM »

Bob is right, it looks like the chamfer is missing. The correct hub for that drum should also have a slight chamfer at the top of the screw hole to accept the tapered portion of the flathead screw which is longer than the drum is thick. ---\ /--- �Really bad drawing ;)
Posted by: Bob W
« on: June 26, 2011, 07:51:33 AM »

Quote
Yes, I had forgotten, the old style drums are on the inside of the hub and the new style are on the outside of the drum. Isn't that right? So if his drums have the screw holes they are for the late style brakes.


That is correct. The 3 small holes should have a chamfer for the flat head retainer screws. In the photo it appears the chamfer is missing from the new drums.
Posted by: Chasm
« on: June 25, 2011, 10:02:42 PM »

Quote
Moved forward with taking old cylinder/shoes/etc off and replacing with new. Only to discover that the vendor sent me the wrong shoes. �>:( �Label on box is right, part inside was wrong.
 

If it's more OMIX-ADA stuff, you have to beware! I have had mostly negative experiences with their products. Quality control is obviously not their forte'! ;)

I am sure I am not the only one on this forum that has had bad luck with OMIX parts... >:(
Posted by: Carls_jeep
« on: June 25, 2011, 09:39:41 PM »

Yes, I had forgotten, the old style drums are on the inside of the hub and the new style are on the outside of the drum. Isn't that right? So if his drums have the screw holes they are for the late style brakes.
Posted by: rocketeer
« on: June 25, 2011, 12:31:21 PM »

Those are for later model jeeps.

Larry
Posted by: Gunslinger
« on: June 25, 2011, 09:18:10 AM »

Lets talk about those drums for a minute, I had the same issue with mine, for some crazy reason when the replacement hubs came out they changed the design orientation, instead of the hub going on the outside as the originals are, they have you put the hub on the inside and tighten it to the drum using the 3 small screws. This way when you tighten the wheel onto the hub, the wheel studs hold the whole assembly together.  

If you assemble the new style hub and drum the way it is in the originals, your hub will not line up with the pin hole in the axle as it will be too far out, and the drum will probably rub the backing plate.  Its a bit of a tricky deal to re-assemble the hub and drum, I drove my old studs out of the old hub with a 2lb hammer, when I re-asembled, I was using a new hub to a new drum with new studs and was able to drive them in securely from the back side, again this is with all new parts, if you re-cycle some parts you lose the virgin tolerances and things start to get loose.

Posted by: 3aJeeper
« on: June 24, 2011, 05:19:24 PM »

Carlsjeep - tried the wobble test. Pressed the hub back on by hand (w/o the key) and tried to wobble it and it didn't budge even a little....actually had a harder time getting it back off than the first time! So I think the taper is still in pretty good shape.

Moved forward with taking old cylinder/shoes/etc off and replacing with new. Only to discover that the vendor sent me the wrong shoes. �>:( �Label on box is right, part inside was wrong.

Will update with progress...but likely just more questions! �;)

Thanks for the help.
Posted by: rocketeer
« on: June 23, 2011, 07:44:08 PM »

All good advice Carl.

Larry
Posted by: Carls_jeep
« on: June 23, 2011, 11:32:28 AM »

Take your drums to a shop that turns them and have them measure them. If the drum is in spec and is not grooved from wear then just use them as is, OR, have him just do a clean up that may leave some light grooves. DON'T try to take all the grooves out, just smooth it up as needed.

Another thing is, if the shop has a shoe grinder have him fit the shoes to each drum so there is little wear in required. Not many shops will still have the shoe grinder now days.

As hard as it is to adjust the brakes on these Jeeps it is best to have the shoes fit the drum to start with.

The reasons I acquired a drum/rotor lathe with a shoe grinding feature is I don't trust others work, they machined off to much metal and they almost always claimed they were to far gone to machine.  
Posted by: 3aJeeper
« on: June 23, 2011, 08:32:20 AM »

Carlsjeep - will try your suggestion on checking for wobble. I don't know if the PO turned the drums or not.

Rocketeer  - depending on the wobble test I may have to try your shim approach. The Vernco site is awesome. Anything with pictures is great!

I am no mechanic but having a good time playing at one....I really appreciate the suggestions from the forum.

Should really get at it this weekend. I'll let you know how I fair.

Thanks to all!
Posted by: rocketeer
« on: June 23, 2011, 08:05:30 AM »

If the hub is slightly loose or if the keyway is slightly worn there is a way to patch them. In the old days we used very thin copper as a shim. We would cut a small piece to fit around the axle stub, less the keyway, and slid the hub over it. Torque down the nut and you're back in business. Same for a worn keyway. With a worn keyway you may only need a then strip down one side of the key to tighten it up. The alternative is a new hub and/or axle shaft.

Also keep in mind when putting the key back in that it only goes in one way, with the angled end away from you. The long shoes face forward, not rearward as in most brake systems.

Good info on Vernco's site:

http://www.vernco.com/Brakes/id348.htm

Larry
Posted by: Carls_jeep
« on: June 23, 2011, 12:00:22 AM »

The hub came off easy because the nut was loose. The loose nut and hub has worn the axle and hub taper and possibly the keyway in both. I would try putting the hub/drum back on without the key and see if the hub wobbles on the axle. If it fits snug with no wobble you may be ok.

Now about the drum. If the hole for the hub is the same size in the new drum as the old drum and the width of the drum, internal diameter of the drum and everything else matches it will work. You will have to press the studs out, remove the old drum, press the studs into the hub and then put the drum on the hub. You won't have screws to hold the drum on the hub but when the wheel is on, the drum won't come off.

The only way you can use the new drum is if it is an EXACT match in all dimensions to the old drum.

Has the old drum been turned to the max diameter? If not have it turned and reuse it.
Posted by: 3aJeeper
« on: June 22, 2011, 10:41:40 PM »

Interesting that two folks have identified that this is the wrong hub. The OMIX-ADA kit I purchased was billed as:
            
"Drum Brake Overhaul Kit Does LH and RH Front and Rear. Jeep CJ2 1948 after Serial 215649-1949 CJ3A 1948-1953."

The plate on the jeep clearly identifies it at a 51Cj3a, so maybe something is not right with the kit.

So I think the best route may be to investigate why the hub came off so easy and if it's ok, keep it and just replace all the other parts (wheel cylinder, shoes, springs, etc). The jeep was sitting for some time and I want to be sure the brakes are solid....getting it to run is nice...getting it to stop is mandatory.

Posted by: Matto
« on: June 22, 2011, 10:04:37 PM »

Ditto on the wrong drum. That new drum has three screw holes to screw it to the hub behind it. CJ3B and CJ 5,6 use these. Alot easier to service.
Posted by: rocketeer
« on: June 22, 2011, 06:54:39 PM »

First, that's not a good sign that the nut was loose and you could pull the hub off by hand. When they are that loose almost always the keyway in either the hub or the axle shaft is damaged, sometimes both are. Usually too the key itself is buggered. Often the hole in the hub is wallowed out as well.

Second, why are you changing drums? Are they damaged? Frankly I would not try to take those hubs and drums apart unless absolutely necessary. They are held together by the studs being hydraulically pressed in from the rear. The studs are swagged to force a tight fit in the hub. If you must do it you will need to have a shop do it with a hydraulic press in order to avoid damaging the hubs. You also should replace all the studs with new ones as ones that have been pressed in and then pressed out won't be as tight the second time.

Third, those don't look like the right drums for this application.

Here's a recent discussion of the same issue:

http://cj-3a.com/forum/YaBB.pl?num=1303485390/9#9

Larry