A Question about rear axel shims

[46HARLEY]

Would like to know thoughts and fixes on rear drum rubbing on emergency brake carrier. Saw that I can buy shims and some suggestions to make my own. How much is shim is to much. If you have done this where did you acquire the shims. Lastly is there any concerns or hints that I should know ?
Thanks Larry

[Ruth]

I'll be watching this one. I have always had mixed feelings about using shims.

If the taper between the axle and the hub hold keep it from moving, how does the work with a shim between them? I would think there would be some movement and then only the axle key would be doing the holding?? I don't know.

Axle shims are available from most of the vendors if you go that route. https://www.snydersantiqueauto.com/p...8129&cat=41823

[nkaminar]

I have bought mine from Snyders. I have one shim in each axle. I tighten my axle nuts to 100 foot-pounds. The taper is what keep the hub from moving relative to the axle. The key is there for a backup. The shim will not effect the axle to hub lock with the right torque on the nut. If in doubt use some of the red Loctite. The nuts should be checked after 100 miles and then each year or more if you are driving across the US.

[jw hash]

you can make your own, it is best to buy some. usually, one shim will move the drum out far enough to clear. however, I do not like to use more than one. two reasons. if you stack up the shims, they will over time self-destruct and sometimes you will not be able to put the cotter key in.

[Ruth]

Originally Posted by nkaminar

I have bought mine from Snyders. I have one shim in each axle. I tighten my axle nuts to 100 foot-pounds. The taper is what keep the hub from moving relative to the axle. The key is there for a backup. The shim will not effect the axle to hub lock with the right torque on the nut. If in doubt use some of the red Loctite. The nuts should be checked after 100 miles and then each year or more if you are driving across the US.

Thanks for that, nk. I do torque to 100 ft-lbs. Just wasn't sure about the shims.

[Bob Bidonde]

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Shims are a good bandaide for a problem that needs fixing the next time you open the differential.

[P.S.]

Like Bob said- "Shims are a good bandaide for a problem that needs fixing the next time you open the differential."

But it is still a band-aid for the real issue. And never EVER use more than one shim. If one shim isn't enough, swap the axle.

[katy]

Originally Posted by P.S.

If one shim isn't enough, swap the axle.

If one shim isn't enough, try a thicker shim.

If/when installing shims make sure everything is surgically clean, no oil or grease on the axle, the shim, the key or the hub, the same goes when installing hubs w/out a shim.

[P.S.]

Originally Posted by katy

If one shim isn't enough, try a thicker shim.

THIS!!! But within reason. NEVER stack multiple shims on the axle taper.

[46HARLEY]

Ordered the shims, will have to see how it works out. Thanks for all the responses.

[Ordsgt]

I just put a shim in a club members left rear axle. It appears as the axle was fine but someone (unknown who) did not tighten the axle nut to 100 ftlbs and set it up like the front wheel bearings, tighten then back off and put cotter key in. This was found when I was changing a wheel out for him and noticed a lot of play in the drum. Tightening up the nut to 100 ftlbs made rubbing contact in the brake. The nut also went past the hole not allowing a cotter key. One axle shim from Snyders and everything was fine and nut tightened up properly allowing for cotter key. The other side did not need a shim and tightened up properly. From what I could see the axle was the same on both sides no wear noted or measured. The car still had original steel drums and I believe that was where the wear was. Advised owner to look into replacing the drums with new cast ones

[gdmn852]

Hello, on post 11,the same guy must have worked on my car too . That is how it was when I bought it ! Must have thought it was similar to front wheel bearing, must have driven it for awhile as it wore the wheel hubs a bit , and would click sometimes, another future project, new axles!

[dave in australia]

Originally Posted by Ordsgt

I just put a shim in a club members left rear axle. It appears as the axle was fine but someone (unknown who) did not tighten the axle nut to 100 ftlbs and set it up like the front wheel bearings, tighten then back off and put cotter key in. This was found when I was changing a wheel out for him and noticed a lot of play in the drum. Tightening up the nut to 100 ftlbs made rubbing contact in the brake. The nut also went past the hole not allowing a cotter key. One axle shim from Snyders and everything was fine and nut tightened up properly allowing for cotter key. The other side did not need a shim and tightened up properly. From what I could see the axle was the same on both sides no wear noted or measured. The car still had original steel drums and I believe that was where the wear was. Advised owner to look into replacing the drums with new cast ones

I had the same issue with the RHS of my Tudor. I swapped from steel to cast drums, so a different hub, and found I no longer needed a shim. So it is not always the axle, sometimes it is the hub.

[Hitman]

Originally Posted by 46HARLEY

Would like to know thoughts and fixes on rear drum rubbing on emergency brake carrier. Saw that I can buy shims and some suggestions to make my own. How much is shim is to much. If you have done this where did you acquire the shims. Lastly is there any concerns or hints that I should know ?
Thanks Larry

Everyone seems to be focusing on the shim and the axle taper. It could have nothing to do with those at all. We need more details from you on where it's rubbing the e brake carrier.

Is the carrier installed correctly? Is it bent at all? Often when you grab the emergency brake at speed, the carrier gets bent. Make sure yours is not bent. Are your studs installed correctly and flush on the back/hub side? I've seen studs that are welded, and the welds will rub, or people have installed incorrect studs that don't sit flush against the hub and will rub. Are the pins and springs installed in the carrier correctly? Again, installed incorrectly they can rub against the hub.

Lots of things to check, a shim is just a bandaid and really only meant to address a taper issue, it's not meant to move the drum/hub out to reduce conflicts. I wouldn't use a shim to fix your rubbing issue. I've seen rubbing e brake carriers finally catch and lock up a rear wheel. That's a dangerous situation!!

[Ordsgt]

In the case of the car I worked on it was definitely a drum issue. The installed drum went on so far as to completely expose the hole for the cotter key well past the castellated nut. Measurement of axle showed no signs of wear. Installation of 1 shim put drum out to proper location and installation of the nut and cotter key after 100 ftlbs of torque. Car had steel drums and being loose opened the up a bit. I still recommended that he do a brake job and replace all drums. As an aside he put 5000 miles on the car last year.

[46HARLEY]

Just put a shim in and made a considerable difference. When I received them thought it would be thicker, it was only about .005. No more contact with the e-brake carrier. On to the next thing.

[nkaminar]

The amount that the shim moves the hub out is equal to the thickness of the shim divided by the tangent of half the angle of the taper. I don't know what the angle of the taper is, but for example lets say it is 7 degrees. A 0.005 thick shim would then move the hub out 0.082 inch. 0.005/Tangent(7/2)

This also applies to any wear in the hub or axle. With the same taper 0.005 wear would move the hub, and drum, IN 0.082 inch.

[46HARLEY]

Originally Posted by Hitman

Everyone seems to be focusing on the shim and the axle taper. It could have nothing to do with those at all. We need more details from you on where it's rubbing the e brake carrier.

Is the carrier installed correctly? Is it bent at all? Often when you grab the emergency brake at speed, the carrier gets bent. Make sure yours is not bent. Are your studs installed correctly and flush on the back/hub side? I've seen studs that are welded, and the welds will rub, or people have installed incorrect studs that don't sit flush against the hub and will rub. Are the pins and springs installed in the carrier correctly? Again, installed incorrectly they can rub against the hub.

Lots of things to check, a shim is just a bandaid and really only meant to address a taper issue, it's not meant to move the drum/hub out to reduce conflicts. I wouldn't use a shim to fix your rubbing issue. I've seen rubbing e brake carriers finally catch and lock up a rear wheel. That's a dangerous situation!!

When I acquired the car, the e-brake carrier was bent and broken. Replaced the carrier and that’s when I became aware of the interference. I believe it was because of wear on the axel and or hub. Shim will work for now, need to look into replacing some things. Thanks for your thoughts. Larry

[46HARLEY]

Originally Posted by nkaminar

The amount that the shim moves the hub out is equal to the thickness of the shim divided by the tangent of half the angle of the taper. I don't know what the angle of the taper is, but for example lets say it is 7 degrees. A 0.005 thick shim would then move the hub out 0.082 inch. 0.005/Tangent(7/2)

This also applies to any wear in the hub or axle. With the same taper 0.005 wear would move the hub, and drum, IN 0.082 inch.

Thanks for the math, that looks about what the axel nut moved compared to the cotter pin hole. Larry

[Fullraceflathead]

Because it's such a small angle of taper a small amount of shim moves the hub quite a bit.