I need to know if the 68-70 A-body spindles w/disc will work with drum brakes? The only replacement spindles I have located are for disc brakes.
I understand the brake anchor boss is 0.610" shorter on the spindle/disc, other than that, they are suppose to be identical in all other aspects. Can I install a spacer to compensate for the shortness on the spindle boss so I can attach the drum backing plate?

The owner of this 68 Cutlass wants to keep drums. However, his spindles have excess wear on the undersides where the inside bearing rides. The wear is between 0.005 - 0.007 depth.

Any assistance will be greatly appreciated.

 

No, they will not work. Everyone who has converted to disc brakes likely has drum brake spindles collecting dust in the corner of the garage. Get a used original not an incorrect imported replacement.

 

Joe,

Can you explain as to why they will not work if the only difference is the brake anchor boss height? If they are otherwise the same, then I should be able to turn a sleeve spacer to compensate the difference and everything else should be the same, correct?

 

Yes, you can machine a spacer. This means that the bolt that holds the wheel cylinder to the spindle is now in bending instead of shear. Not the best design structurally.
My bigger point is why? The world is littered with A-body drum brake spindles that people throw away when they convert to discs, and they aren't imported crap. Have you even tried to find one?

 

Joe,

Yes, I have located used ones. However, the owner is against used ones. His point is, we don't know how many miles are on these used spindles. As far as the wheel cylinder, that should not be affected as it bolts to the drum backing plate. The sleeve spacer applies between the spindle brake bolt boss and the backing plate brake anchor insert, which anchors the top of the shoes and springs. This car is original matching numbers and that is why the owner is persistent to stay with drums. I have tried to get him to upgrade as there are a few other non-stock changes, but he won't budge.

 

The load from the wheel cylinder transfers from the backing plate through the bolt to the spindle. The stock spindle keeps the bolt in pure shear. This is both stronger and stiffer. Any spacer will have clearance that allows the bolt to deflect. This is a bad design structurally. Point out that the OTHER spindle on the car is used, as is the frame, suspension arms, etc, etc. If your customer is that ****, have the replacement spindle magnafluxed. Did I mention that the spacer is a bad idea?

 

And THAT'S even more reason not to use a half-fast repair with Chinesium parts.

 

Joe,

No, you didn't mention a spacer was a bad idea! However, I'm glad you did! I appreciate your time and expertise with this issue I'm having. This sounds a bit crazy but another mechanic told me to center punch the area that is worn so it swells the metal slightly. Supposedly the bearing will fit snug and the inner collar of the bearing may not turn which won't hurt anything, so says the guy in the corner. Ever hear of this trick?

 

I can't comment without more info on the problem and photos of the old spindle. Are we talking about a bad wheel bearing that gouged up the spindle? If the owner is that worried about originality, have the old spindle welded and re-machined. I'd worry about center punching, since that's a great way to initiate a crack.

 

Another option is to turn down the worn area and machine a press-on bushing to restore the diameter.

 

The spindle is in good shape other than the wear on the underside of spindle. It's such a small depth of wear that I believe the sleeve is the best route. Thanks much Joe.