Hey board,

I'm new here but I did search the archives for a while before I posted this...

One of my brakes is shot, the rear right to be specific. I did a rear brake job a few months ago with new pads and resurfaced rotors. When I did it, that caliper had the piston fully extended to the point where brake fluid was leaking out.

Anyways last week I started hearing brake noises...sounded like a muffled train stopping. Figure last Sunday I had off and I was already going to change the oil and valve cover gasket, it's just about due to rotate the tires so I'll do that and take a look at the brakes while I'm at it.

Here's what I saw: The rear left braking system was fine. The rear right rotor was severely gauged and extremely rough and there was a lot of wear on the pads considering they only had a couple thousand miles on them. I know that I'm going to need a rotor and pads, that's beyond question...and I'm pretty sure I need a caliper. I'm on a very strict budget and can really only afford used parts (as long as used parts are acceptable...)and I've got a line on a junkyard to sell me the caliper and rotor together for $25 which I think is a great price. It's from an 87 740 (didn't tell me anything else). The problem is I have no idea what size my piston is nor do I have any idea what size the other calipers piston is. I have no way of getting anywhere for parts without that car so his reccomendation of bringing down the caliper and comparing it really doesn't work out too well.

Is there any way of determining the piston size without taking out the caliper and measuring it? These brakes are on their last limbs and I can't drive the car much further without fixing it (especially since my e-brake doesn't work anymore)...but unfortunatly I can't get to work without it and I really can't afford parts without borrowing money until next weeks paycheck...Junkyards close the same time I get out of work and my only day off is Sundays...so I'm really in quite a jamb here until I can find someone to spot me the money and even go down to the yard and pull it for me.