The problem here is simple. Went to the parts store to pick up a rear wheel cylinder for my '94 Bonneville SE and when I got home, it didn't look at all like the one on the car. The main difference is that the 'new' one has the bolt holes for attachment to the backing plate above the bleeder. The one on the car as the bolt holes below the brake line.

The rear brake setup looks a lot like the one on a friend'* '89 Buick. Is it possible that Pontiac put a 'new old stock' brake set on my car? What do I ask for at the part store?

If you put up a picture of the one they gave you, we should be able to tell you if it'* the wrong one quickly. It sounds like the wrong part.

See, the bolt holes are like Mickey Mouse ears, but should be more like ore cart wheels!

Actually..that looks right on .. but then..I haven't seen one lately.

I'm with Bill....that looks right. Can you post a pic of the old one? I don't see where the new one could be wrong.

Keep in mind..they can be a pain in the buns to get in on certian cars..Although..I think ours are easy..

Trying to think back to the '93, but if memory serves me right (which it may not) I thought the bolt holes were closer to the bleeder screws and contained within the circle. Also, that the whole circle area was raised. I do remember trying to get those torx bolts out was a PITA because of a lack of room.

This isn't my picture, but it does show the wheel cylinder I have.

My factory service manual does show the configuration of the cylinder'* brake line inlet, bleeder and attachment bolt holes from this brake backing plate view.


So, maybe I should try AutoZone instead of Advance!

In that case.. sorry to have misled you. It has been a while since I've seen one first hand... or maybe there was a slight change at some point over the years.

I prefer to research the part online at two or three major parts suppliers like Parts America/Autozone/Napa. They typically have a good reference picture of the actual part. Then you can go in armed with the exact part number you need and take the possible problem out of the equation.

gmpartsdirect shows the P/N to be:

18060172