Edbert.Net home

67 GTA home

Ever since adding the 17" inch FoMoCo rims to my car the appearance of the stock 10" power Disc rotors have been terrible. They look like the rotors off of the Honduh owned by the kid down the street. This effect was only made worse by the 12.25" rotors on my rear discs. While the stopping power of the factory disc setup might have been state-of-the-art 40 years ago, it has nothing to compare with modern oversized rotors and floating calipers. I decided long ago to try and get a set of 13" rotors and PBR calipers off a a 96-04 Cobra onto my car, many folks were working on a caliper bracket to allow this but for a variety of reasons those plans always fell through. Until recently that is, "Mustang Steve" (http://www.mustangsteve.com/) is now selling the necessary parts for just such a conversion. The kit I bought was just the two brackets and most of the mounting hardware, but he sells entire kits if you need the rest. This page will illustrate the conversion as well as provide some more information on the problem I had initially. This is just for illustration purposes and only indicated what I did, I make no recommendations for your car and all possible disclaimers apply if you are a scumbag-lawyer-type.

You can barely make out the rotor in the top photo, to me more specific you can see all the open space between the puny rotor and the big wheel, but here's a better shot of the cosmetic problem.

 

WIMPY WIMPY WIMPY! They look fine behind 14" Styled Steel wheels or even 15" Magnum 500s, but not with 17" Bullits.

 

Beyond the cosmetic issue there's a hug difference in stopping power too, this photo illustrates the difference clearly.

 

One side of the bracket from Mustang Steve.

 

The other side of the adapter bracket. You can see there was quite a bit of milling when compared to the stock unit.

In order to get the new rotors onto my car I had to acquire some drum brake parts. The fellow I bought the hubs from had a hard time getting the drums off the hubs so he shipped the whole things to me. I soaked them with penetrating oil for 2 weeks, I used a torch, I used a claw hammer, I was about to give up and considered buying a new set of hubs (about $70 each) and probably should have but I'm a cheap bastid. So I took a 5-pound sledge to them with these results...

As you can see the drums "came off" rather readily.

 

There was some small parts of the drums that still wanted to stay where they'd been for almost 40 years but they came clean finally.

When I did a trial fit I found some issues...

The freshly released hub fit fine on the 67 PDB spindle, drum spindles are not required. I have a set of 71 Drum spindles which are a bit beefier but the stock bearings did not fit and I am reluctant to try and make it work for now.

 

The bracket fit on VERY tightly, so much so that the bolts were not required for the test fit.

 

When I attached the caliper I found this small gap, approximately 3/32 of an inch. I inquired from my friends on Stangnet and from Steve himself if I should use shims like Willwood and Baer use in their kits. The correct determination was that the rotor was not seated all the way down on the studs. You can see that they do not protrude very far in the pictures below (note the caliper shown in these pictures belongs on the passenger side not the driver's side as shown, if in doubt...the bleeder points up).

 

Common thought was that using a machine shop was not necessary, I should be able to seat/press the rotor onto the shoulders of the studs by tightening the lug nuts using a star pattern.

 

I tightened them a great deal and was able to seat the caliper (still just test fitting) completely and tighten it down, but there was a very slight "wobble" in the rotor when spun, a visually perceptible wobble would probably be catastrophic on the road so I decided to take them to the machine shop. The machine shop determined, after removing the one I had "pressed" on, that the studs were damaged and would not seat properly, plus at least one stud had some gnarled up threads so I went to the local parts store for some new studs. I wont name names but one store wanted $11 each and the other wanted $13 each! So I ordered a set of 10 from NPD for $1.25 each (remember I'm cheap?) and waited. When they came in I had the shop press out the old ones and press in the new ones. With the new studs the rotors literally slipped onto the hub much like they did on my 1997 Cobra...DUH!

 

Here you can see the slight difference in the design of the studs, the "shoulder" of the old one was larger towards the outside where the threads are and the shanks had a slightly concave curvature to them. The new ones were straight, there's a different manufacturing process too, the shank seemed to be a two-part unit on the old ones.

 

The cleaned up hub with new studs.

 

I had them install new races while it was there with the hydraulic press.

 

Like I said, the rotor slipped right on, you can see there's a little space around the openings.

 

Four grade-8 bolts hold the bracket to the spindle, I had to make slight adjustments to the aluminum to get it right, one bolt had the threads stripped when I applied a little too much encouragement to it.

 

Greased the crap outta the new bearings with synthetic grease and installed new seals.

 

Since I was using all new hardware I used the new retainer. They don't use a bolt with castle-nut-cap anymore, guess manufacturing costs are too high, but these fit perfectly anyhow.

 

My wheel spacer, dust cover (says made in China on it damn it!) and powder-coated caliper in place.

 

Final product...THANK'S STEVE!

It not only filled the space but also moved the rotor further out towards the wheel, got three birds with one stone.

For more information on the brake system for this car click here.