Cheap Big Brakes Part II

[Lynn]

You guys with machine shop capabilities and access will get a kick out of this I am sure.

This is a continuation of my Cheap Big Brakes (CBB) upgrade on the 68 El Camino. You can read about how I put C3 Corvette rotors with 70’s truck calipers on the front here: http://www.camaros.net/forums/16-bra...e-upgrade.html

In the first post there is a link to where I got the idea from a page on David Pozzi’s web site.

The thread showing the mods to the rear, and the hidden trailer hitch is here:
https://www.yenko.net/forum/showthread.php?t=133383

I have always considered myself a bit of a Hack Mechanic. I even hacked that term. A fellow named Rob Siigel wrote a column for years (decades actually) in the BMW car club magazine, The Roundel. Like Rob, I seem to find solutions to problems that are effective and efficient, even if a bit ugly. Fortunately, this El Camino is the perfect platform for my hackness. It is a no hit, almost rust free car, but nothing we would want to restore to factory original. 307 PG car with power steering and factory A/C. Been painted multiple times starting as Grecian Green, then a bright yellow, and now hot rod flat black. .020 over 350 with a forged crank, crane roller cam made for torque starting at 1500 rpm, stock 68 cast iron four barrel and Q;jet. 4L60E trans with stand alone controller. Currently has a 3.36 10 bolt, but I found a cheap 3.31 12 bolt.

I modified the back end to make it suitable to pull my car hauler. I don’t need huge bearings in the rear, as I don’t put too much tongue weight on it; just need it to pull …. and stop. According several who have commented, I should be able to bolt on some 11 inch rear drums. Figured the perfect time to do it was while I was going through the 12 bolt before installing. I really didn’t want to mess with converting the rear brakes to disc, but thought upgrading from 9 x 2 drums to 11 x 2 drums would be a great match for the Corvette brakes on the front.

Turns out it is not so easy. I believe there were a few Monte Carlos in the early 70’s (and maybe a few Chevelle’s) that received 11 inch rear brakes. Good luck finding those used parts. No one makes replacement backing plates for those big brake Chevelles. Virtually every source I checked indicated that backing plates off of a full size Chevy 12 bolt would bolt on to the Chevelle rear (or Camaro for that matter, as the backing plates and ends of the axle tubes are the same). No so. The full size Chevy has a larger axle tube. I purchased a set of 11 inch backing plates (apparently for 11 by either 2.5 or 3, as they were off set more than my Chevelle backing plates. All of the 11 x 3 drums I found were drilled for the bigger 5 inch bolt pattern, like what came on the big Buick or a Cadillac, instead of 4.75.

My research indicated that a late 60’s full size Chevy could have 11 x 2 drums in the rear. Bolt pattern is 4.75. One of the kind members on this site (L78Steve) was parting out a 12 bolt rear from a 69 Caprice. He checked, and it had 11 inch brakes in the rear. Steve was kind enough to send me the drums, the backing plates and all the associated hardware for free. All I had to pay was shipping. What a deal.

Sure enough the center hole in the backing plates is considerably larger than the ones for A body or F body cars. Hmmm. I have free brake drums and free backing plates. A little crusty, but still solid. Decided it was time to hack out a solution.

More to come.

Below are pictures showing the difference in the backing plates. This nicely primered backing plate isn't one that Steve gave me, but is one of the ones made for 11 x 3 brakes. Hole and bolt pattern is exactly the same though.