Being new to owning a 3rd gen T/A I have a question. My 92 with WS6 and crosslace 16X8 wheels has this spacer between the rear wheels and the brake drum. Getting the car state inspected the mechanic removed them and left them off because he said they bound the drum on the hub and he felt they didn't leave enough stud length installed, for the lug nuts.

So..do they go back on? stay off? Is there a different drum that doesn't have a bevel around the hub opening that gets crushed with the spacer?

What's the spacer there for anyway?

Help

 

only drum cars with iroc wheels got the spacers. if the car had rear disk it didn't have the spacers. apparently the disk brakes sit an 1/8th inch out further than the drums and that's what they're there for. that's my theory anyway.

 

Allright,thanks!

Is it a problem to run without them? Is it just for alignment purposes or is there a clearance problem associated by running without them.

 

its up to you too leave them off or on, it isnt going to cause any problems or clearance issues, 1/8" cant hurt anything especially spacing

 

my 86 iroc with rear disc brakes had the spacers with the factory 16 inch wheels and they are gm and i know its possible they were put on later but who knows

 

I'd really like to know why GM put them there? I can't seem to find anyone locally that can tell me what the technical need for a spacer on the rear wheels was/is for?

 

My 85 IROC, J65, was equipped with the spacers too (so who knows what is in GM's collective nogging). Iron drums and alum wheels might be something to consider.

JamesC

 

Gm orginnally installed them for the new 16" wheels and the switch from aluminum drums to the iron drums. There was adifference between the two of about .187, so a spacer was used. Over the model years the use of this spacer became hit and miss at the Assembly Plants. Even some Disc brake cars had them. It will not be any problem to run without them. Also a lot used Camaros do not have them because they were disgarded over the years.

 

Okay, so we hunted down a GM service writer from back in the day (80-ish thru now) and he indeed had a whole earfull to give me about it.

Some of this made sense,some if didn't. So for free advice it's worth just that.

He said GM had run out problems with 16" wheels and caused some vibration problems. He said that if the car is relatively low mileage that I would find a paint dab on the inboard side of the spacer and a corrosponding paint dab on the drum or rotor. The spacer or shim as he called it is not evenly thick around it's diameter and it could be .125+ thick in spots and less at the opposite spot on the spacer.

He said as these cars got older and came in without the paint dab he was required to put a dial indicator on the outer edge of the mounted wheel and rotate the shim to cure the run-out and then re-apply a marker dab of paint on both sides.

I explained that it felt as though the spacer was bearing down on the beveled flange of the drum over the axle hub and distorting the drum and he agreed that probably was happening.

He couldn't remember if factory drums had such a prounonced outward beveled flange or not but maybe aftermarket drums do and that causes binding.

In the end he said whatever I could live with is okay to do.

Now, I found another service tech that has been at a GM dealership since 88 and even ordered and drove an 89 GTA and he says his never had them and that if anything it was to correct an alignment tracking difference between disc rear and drum rear cars ( his was disc) and he said that if it was his and they were binding the drum's inner flange then leave them off. Either that or have machine shop hog out 1/4" from the inner of the spacer to get it away from the drum flange.

So, for now they are back on, but I will probably take them off tomorrow.

 

My opinion is the above statements are fiction with a little BS added for effect. Just what a dimwit service writer wouild say. I will stand by statement what the spacers were used for. (Note: it was a short explaination)