C2:67 Parking Brake Shoes

[Gerard F.]

Getting ready to address my 67 parking brake (or lack thereof) with new shoes, and a hardware kit, cables and all. I've tried all the adjustments, but I think I have a broken spring on one side.

As I understand from the Overhaul Manual and previous posts, one needs to drill out the original rivets between the rotor and the spindle to remove the rotor, and that replacement of the rivets is not necessary, as the wheel lugs then hold the rotor in place.

For those of you who have done this before, here are a few questions:

1. What holds the rotor in place when you pull a tire?

2. Is there any way to fix the position, of the rotor against the spindle, without pulling the spindle and replacing the rivets. I was thinking about putting something under the lug nuts, or some replacement for the rivets.

3. What size drill bit do you use to drill out the rivets. (Drilling out original parts will be a trauma for me).

I have been told to take this to a brake shop, but a want to DIY. I feel a story coming on, on this project.

Having fun,

Jerry Fuccillo
#42179

[Joe C.]

Re: C2:67 Parking Brake Shoes

Jerry,

The caliper, as well as the emergency brake shoes will hold the rotor in place after the rivets are removed. Rivets are not needed, nor were they ever needed.
Just for fun, why not check the runout on the rotor before you drill out the rivets and remove it. I'll bet you that it's going to be more than the recommended .003-.004(?). Just mark the rotor and spindle before you remove, and replace in the same position! Once the rotor is removed, for MORE fun, why not check the runout on the spindle with a dial indicator! Let us know what the runout is. NOW, you are in a position to set your spindle/rotor orientation for least total runout!

A couple years ago, I broke (sheared) the right rear (GM) spindle on my '65 (holeshot!). The measured runout on the original unit was in the neighborhood of .006". I purchased a replacement spindle from International Axle, and the measured runout was LESS than .001". After I installed my new rotors, the total runout was about .001".

Use a large (1/2") drill bit to drill the heads off the rivets. Drive them out with a drift once the heads are removed.

Be sure to use all new stainless steel e-brake hardware for the replacement.

Good luck, and see you soon! Why not drive over here, rather than fly, once you've got your nice, new e-brake hardware installed, along with your nice, zero-runout rotor/spindle assemblies.

Joe

[Joe L.]

Re: C2:67 Parking Brake Shoes

Jerry-----

First of all, as Joe states, it is not necessary to replace the rivets or otherwise retain the rotors once the rivets are drilled out. However, I like to do it, anyway. What I do is to somewhat countersink the rivet holes in the rotor, tap the existing rivet holes in the spindle flange for 3/8-24 thread, and install the machine screws as pictured below. The countersinking of the rivet holes is necessary so that the full head of the screws sets below the plane of the wheel mounting surface. Since the existing rivet head orifices in the rotor effectively accommodate most of the countersunk area of the screws, the actual amount of additional countersinking is quite minimal. What's important is that the finished product does not have the screw heads higher than the plane of the wheel mounting surface. The particular screws pictured are a stainless steel screw which are harder to find. However, you can obtain black-oxide-finished original screws of this configuration at Orchard Supply Hardware. That's mostly what I actually use, anyway; I just didn't have any handy to photograph.

Regardless of what you do, though. I STRONGLY encourage you to follow Joe's advice and measure the "before-and-after" runout on the discs according to the procedure specified in the service manual. Like Joe, I would be very interested in hearing what they turn out to be.

As far as your reluctance to drill out the original rivets, I share your concern. I used to do this and I wish I never had, but not for the reasons of "originality". As a matter of fact, in 1974 Chevrolet changed the procedure for rear spindle service and recommended that the spindles NOT be separated from the rotors via drilling out the rivets except in cases where a replacement spindle or rotor was needed. It IS possible to remove and re-install the rotor and spindle as a unit. This procedure is covered in 1974 and later factory service manuals. It does require the use of one additional special tool to perform the re-installation and another special tool if the outer bearing is to be removed from the spindle.

The major problem, though, with removal of the rivets occurs when one replaces a rotor or spindle. The GM spindles usually have excessive runout on the flange. That's because, originally, any runout on the spindle flange was, effectively, corrected when the riveted-together rotor and spindle had the rotor surface machined as an assembly. This was ok in PRODUCTION. However, unfortunately, GM SERVICE spindles are, apparently, made to the same "loose" flange runout specs as the PRODUCTION spindles and this often causes problems. Mating a SERVICE rotor to an original spindle also often causes problems. As long as you make sure to index the removed original rotor to the same relative position on the original spindle, there usually won't be a problem with runout UNLESS there was a problem before removal of the rotor from the spindle.

In the latter regard, and although it doesn't apply in your case, I agree with Joe that the International Axle spindles are the "way to go" if spindle replacement is necessary. Although some originality is lost since the centers of the IA spindles are notably different than originals or GM SERVICE spindles, the IA spindles have a spindle flange which has less than 0.0005" runout. That pretty much ensures problem-free runout on the rotor.

[Phil P.]

Re: C2:67 Parking Brake Shoes

remove both half shafts at the spindle end and put them on top of the torque arm---remove the calipers---remove the spindle nut and pull the rotors with the spindles---you can purchase new grease seals for the spindles and re-pack the bearings as you would do the front wheel bearings---i feel this would be quicker than drilling out the rivets and it is time you checked the rear bearings anyhow---this (from a tech point) will not be any harder than when you did your steering col.---good luck,phil

[Gerard F.]

Re: C2:67 Parking Brake Shoes

Joe,

Thanks for the advice. I'm going to do a little more planning on this and decide whether to pull the spindles or drill the rivets. Joe L's idea about replacing the rivet's with screws is great, and is what I had in mind, if I drilled the rivets. But pulling the spindle with the rotor attached might be easier, and I guess I could get the spindle/rotors turned, if need be.

Decisions, decisions, but I don't rush into things, and the way I work it might be a while. Gonna find a dial gage today.

Driving the 67 to New Jersey this July is out of the question for me. But I'm gonna enjoy driving your '85 from New Jersey to Boston.

Regards,

Jerry Fuccillo

[Randy R.]

Re: C2:67 Parking Brake Shoes

I am in the process of reassembling the rotor/callipers on the rear end of my 67. The rivets attaching the rotors were drilled out years ago. I measured the runout of the left disc and it is about .008, twice the recommended amount. I found some old information from Stainless Steel Brake Corp. that states they can supply shims to remedy the excess runout. I have not called them to confirm this but intend to next week.

Randy

[Larry L.]

Re: C2:67 Parking Brake Shoes

One more thing to worry about is the shoe lining materail - It is not generic lining material. The lining material had a high friction coeficient and contained Aluminum. This is from the guy who has the patents on the material when he worked at Delco Morain and Inland designing brake materials.
You can identify the correct material as it is a light tan in color. The difference is an E-Brake that really works and one that almost does. After you got to all touble to get it right you want the brake to really work.
I just bought some E-Brake shoes from Correct Systems 1 330 339 6054 and the material looks similar to the orig. shoes The orig shoes can be identifed by a set of numbers along the side of the lining stamped in dark ink.

The recommendation as to the run out is dead on and don't try to get away with out doing it - you will be sorry.

Correct Systems has a nice set of lines / hoses that fit perfectly at a good price.

[Joe R.]

Re: C2:67 Parking Brake Shoes

Hi Jerry:

I don't think the rivets serve any useful purpose at this point. The purpose of the rivets was to get the rotor machined with minimal runout for the assembled unit. The final turning of the rotor surface was done AFTER the rotor had been riveted to the spindle. That way, a single machining operation compensated for the total runout of both the spindle and the rotor. The rivets were important for the way that GM machined the spindle/rotor assembly, but now that that machining process is complete the rivets have done their job.

Going forward, if you retain the original clocking of the rotor on the spindle, you will retain whatever original runout you had when you started. The lug nuts provide all the retention you need while driving, and the caliper will keep the rotor from falling off when you remove the wheel.

Based on my experience rebuilding my parking brakes a few years ago, I have a few tips to offer:

1) There is only one (possibly two?) correct clocking for the rotor on the spindle because the adjustment hole for the parking brake passes through the spindle. Make sure you pay attention to this detail or you won't be able to adjust the parking brake after assembly.

2) I had bad luck with stainless steel brake shoes, and some other people have had the same problem. The shoes tended to fall off the support "nubs" on the backing plate and get cockeyed. Some people claim that the curvature of the stainless shoes is slightly off and it causes this problem. In any event, I ended up switching to the non-stainless shoes and it solved the problem. I retained all the other stainless parts in the mechanism, so I think the result is still pretty rust proof.

3) You can spend a lot of time optimizing runout. The factory runout is usually pretty good, since the spindle and rotor were machined as a single assembly. If you decide to try and improve runout, you can try alternate clockings of the rotor (which is possible at least on front wheels) or put shims under the low side studs.

[Joe L.]

Re: C2:67 Parking Brake Shoes

Larry-----

That guy is absolutely correct regarding the parking brake lining material and the correct material is ABSOLUTELY, POSITIVELY critical to proper operation of the 65-82 parking brake. It's a "marginal" system, at best, and without the proper lining one stands very little chance of having it work properly. The correct material is a very light tan color (of course, that doesn't mean that all very light tan lining materials are the right ones).

[Joe L.]

Re: C2:67 Parking Brake Shoes

Randy-----

I'll be very interested in what you find out from SSBC regarding the shims; please let us all know. Years ago, SSBC was the sole source for these "tapered shims". However, they ceased to sell them a long time ago due to what I understand was some sort of a patent right issue.

The shims are now back on the market as manufactured and/or distributed by a company called Brake Align (www.brakealign.com). The problem is that they primarily distribute these things to brake shops in kits. It's possible, though, that SSBC can now purchase these from them in bulk and re-distribute in "consumer-friendly" quantities. I hope so because I don't know of anyone else doing this. Perhaps, others will, though.

These shims are an excellent means of correcting rotor runout.

[Joe R.]

Re: C2:67 Parking Brake Shoes

Hi Joe:

In 2004 I was able to purchase several selected shims directly from Brake Align (www.brakealign.com).

I like this shim design because it does a nice job of distributing the pressure under the lug nuts after the shim is installed. If you simply shim one lug nut with a thin piece of metal and have no shims on the adjacent lug nuts, you can create a distortion that seems undesirable. Of course, it is possible to make thinner shims for the two adjacent nuts, which is what I would do if I were making the shims myself.

Brake Align's main customers are brake shops, and they sell the shims in packs of ten, as I recall. Unfortunately, the shims are very expensive, so it doesn't make economic sense to just buy a pack of each of the sizes you might need.

Since they were willing to sell me individual shims for about $15 each, I first measured my runout and then ordered just a few selecetd shims.

I spent a lot of time experimenting with the shims to try and minimize runout. It was a tedious process because the runout did not always respond exactly as expected to the shims. However, I was able to achieve pretty good results in the end. I think I wound up with shims on only two wheels, and was able to meet my goals for the other two wheels by clocking the rotors.

[Gerard F.]

Parking Brake Shoes- Here's my plan

Thanks guys for all the tips, I figured out a plan. Since I just got all the parts ordered, I got the time to think this out.

I did order steel, not stainless, shoes from Wilcox along with a SS hardware kit. (Not too bad a deal at $26 a piece). Also from others a dial indicator.

The plan is that if the runout is in spec, I drill out the rivets. However, I particularly like Joe Lucia's idea about replacing the rivets with tapped 3/8" countersunk screws. (I have already checked them out at Orchard Supply).

I have been around structures too long and know things move under stress, and I like the security of having a solid attachment to keep things in spec. 4 solid attachments forever, is better then 4 which occasionally are not there.

But if I'm not in spec on the runout, it would be time to consider pulling the the rotor with the spindle and maybe getting both turned or shimmed.

Rest assured, I'll keep you posted, but it might be a while. See you in Boston in July.

Jerry Fuccillo
#42179

[Joe L.]

Re: C2:67 Parking Brake Shoes

Joe-----

There's no question that the tapered shims are the best and most practical means for correcting rotor runout on a 65-82 Corvette. I lamented the fact that they were not available for quite awhile even though, personally, I did not need any during that period.

The shims have always been expensive, even when they were available from SSBC. But, they are well worth what they cost (they'd even be worth more than $15, but don't tell Brake Align that).

I'm glad to hear that Brake Align will sell individual shims. I also agree that properly shimming the rotors can be a VERY tedious task. It seems very simple, but it usually doesn't turn out to be that way. Much trial-and-error if one is to achieve a very low runout (like .001-.002" TIR measured on the rotor).

[Randy R.]

Re: C2:67 Parking Brake Shoes

Joe,

I contacted Stainless Steel Brake Corp. They said they have not manufactured the shims for fifteen years. I checked with the local brake shop and they have no shims. They said not to worry about the runout unless a pulse can be felt in the pedal. I think I will persue a supply of shims.

Thank you,

Randy

[Joe L.]

Re: C2:67 Parking Brake Shoes

Randy-----

The brake shop is correct about runout EXCEPT for 65-82 Corvettes and other cars with fixed calipers (VERY, VERY few these days). For Corvettes, excessive runout becomes critical WAY before it gets to the point of pedal "pulsation".

If you determine what runout correction that you require, you may be able to obtain the necessary shims directly from Brake Align.