The Stovebolt Site Forums The Shop Area Driveline Why bolt wheel spacer? POL kit

I have the POL disc kit on my Suburban. I ruined a rotor and bought a new one. The old one has 3 threaded holes in it to secure the wheel spacer. The new one, of course doesn't have it. I figured I could drill and tap 3 holes. But now I'm wondering if it's necessary. Why does the spacer need to be bolted down?

Looks like this.

I assume the spacer keeps the caliper away from the wheel but I have no idea why they bolted it on unless it is just insurance against it being lost during a wheel change?

It does appear that the holes for the studs are somewhat larger in diameter(unless it's the pic angle)than the studs. If so, wouldn't the spacer move some under acceleration and/or braking if not bolted tight? I suppose the wheel could hold it snug though. Just a thought.

It does appear that the holes for the studs are somewhat larger in diameter(unless it's the pic angle)than the studs. If so, wouldn't the spacer move some under acceleration and/or braking if not bolted tight? I suppose the wheel could hold it snug though. Just a thought.

How tight does the rotor and the spacer fit to the hub? I'm thinking that the spacer might be a tighter fit, and is bolted to the rotor to make it hub centric. On the original application of the rotor, the studs were pressed in the behind the rotor and into the hub, which would center it. Since it mounts from the front in this application, the center bore may not be tight enough to allow for proper centering.

may be something as simple as keeping it from sticking to a wheel and being lost during a spare tire installation.

The studs are pressed through the rotor and into the hub. The spacer bolt then goes through the spacer, the hub and threads into the rotor.

I'm thinking that without the spacer bolts nothing is going to move once the wheel is bolted down.

I'm thinking Gregg is correct. It's to keep from losing it. I know people run front drums un-riveted. Are discs really so much stronger we need to bolt the spacer?

I really don't know about the rotors, but there are a lot of things that were bolted together years ago and now they are no longer bolted. Brake drums were bolted at one time and now they just slip on because they have no place to go. If it were mine, I wouldn't worry about the rotor going any where. If I were to drill and tap it, I would wonder if I did the right thing.

It's not going to come off during wheel change anyway. The caliper will prevent that, so just put it on and don't worry about it. I just finished putting new rotors on the wifes Envoy and they were the sameway. After putting new pads in and installing the caliper the only thing that holds the rotor is the wheel and nuts.Larry

One thing I noticed right away is that the spacer eliminates any possibility of the wheel centering itself on the hub. That's not going to influence whether or not the spacer needs to be bolted, but it's going to make it essential that you torque the nuts at every wheel change. When the weight of the vehicle is carried on the studs instead of the center of the hub, the tightest nut carries virtually all the load until the stud stretches or breaks, then the next-tightest takes over, etc. Equal torque spreads the load out evenly and lessens the chance of a wheel coming unglued.
Jerry

Interesting Jerry. Educational as usual by you.

Kenneth, I don't think it is to keep the rotor from going anywhere. The friction of the studs in the hub hold it to the hub. I may be wrong but I think the bolts are just to hold the spacer. And if I drilled and tapped the rotor I'd be concerned about not getting the holes aligned perfectly.


Larry, the spacer fits over the studs. It will come off with the wheel off.

Jerry, thanks for the tip. I always give them a short pblt with the impact. I'll start torquing them.

OK, I just got the right side assembled and took an ice cream break. I'm fixin' to go back out and assemble the left side without tapping the rotor for the spacer.

Thanks for all the comments.

where did you get the replacement parts?

Well I decided to just do it. Two days of fretting over it and I had it done in an hour. I assembled the hub and rotor with the studs. The hubs already had holes just over 3/8". I chucked up a 3/8 drill in the drill press and 'center punched' each hole. Closest drill I could find for the hole was just under the recommended 5/16 for the 3/8-16 threads but my tap cut through.

I have it assembled now. Think I'll wait until tomorrow to clean and repack the bearings.

I got the replacement parts from O'Reilly. The calipers are for a '70s Chevy half ton 2WD. The rotor is same year 4WD to get 6 lug.

The POL replacement rotor is $70. I got mine for under thirty and my hour's labor saved me $40.

Good plan cletis. Every old Hot Rod and Carcraft magazine I have ever read recommended that. Just keep her under 100 MPH.
Carl