Hi! Found a mechanically inclined friend who showed me how to do my valve gaskets last Sunday. He's doing the rear drum brakes on his own car this week, and invited me to come over and do mine at the same time. When I got my car inspected a month ago, the brakes were 3/32" thick, and I was told that they would have started at 5/32" so they would still be just fine. But hey, new brakes are only $18, and I get to learn! When I was at Salvo (for yet ANOTHER window motor, only 1 original left, *sigh*), I asked after brakes, and was told I'd need either 10" or 11"... Obviously I'd like to find out and buy the brake pads BEFORE I've got the wheels off and the drums opened up, and can't drive to the store any longer ;-) Anyone know what a 1990 colony park/ grand marquis wagon would have? 10", or 11"
They should be 11" diam. Even the rear disc brake models are 11" on those big wagons. But, you should also check the shoe width. Some models got narrower shoes. Police and Service vehicles usually got wider shoes. http://frugalmechanic.com/auto-parts/1990-mercury-colony-park/brake-drum?vehicle_engine=34537 Here's one source for drums: http://www.nolimitmotorsport.com/brembo/am-apps-Mercury.html Here's some good info about our Fox-bodied brakes, but the info also deals with the Rear Disk fad following. Fad, not fade. http://vb.foureyedpride.com/showthread.php?t=89336
The rockauto.com website has a good website for checking that kind of stuff because they give the sizes. It looks like yours has different widths available as well. http://www.rockauto.com/catalog/x,carcode,1368592,parttype,1744
You could just make sure all of your options are in stock and get them when you drop the drums to be turned. Everything you need to know can be ascertained from the drums except for wheel cylinder size, if there are different sizes for your car. It will save you a trip I always change everything on the brakes. ie if I'm doing the rear I change the shoes, hardware (springs) and wheel cylinders. It's usually all real old as rear brakes tend to last a real long time. Good luck, let us know how it turns out.
I don't know what the stock wagon rear brakes were. My P72 SHOULD have come with the larger rear drums, but in fact had the smaller civilian brakes. The rearend that I pulled from a wagon to put on my car did have the larger rear brakes. Best best is to pull a tire and measure them. I still think you should just upgrade the rears to the '92+ discs, but if you really want to learn how to work on drum brakes I guess this is a good time to learn.
