Bosal Muffler Gaskets (donuts) Frustration

[lakeside]

I ordered and received a Bosal muffler for my 1987, 560SL, plus the specified gaskets. There are two in the package. My mechanic says that the inlet pipes are different size and the gaskets received are the same size so one is too small. The specified gaskets are 256-077 which I ordered from USAuto Parts (Actually I placed the order with catalyticonverters.com, but the order was filled by USAuto Parts. Bosal spec pages shows the other gasket part number is 256-075 which I have ordered. Here's my question: All the sites I checked for pricing on the Bosal muffler listed only gasket 256-077, as required. Since I received two gaskets it would appear that they should do the job. I'm wondering if there is some "trick" to installing these gaskets so both same size gaskets fit the inlets pipes? I haven't questioned my mechanic because he very reliable and has always done a good job for me. Anyway, my SL, is sitting in his shop waiting and waiting for that damn gasket. By the way I would have ordered a muffler through mercedesshop.com but I was trying to save a buck. $400 for a muffler is a bit steep it seems to me.

[ctaylor738]

I haven't had the pleasure of getting up close and personal with this connection, but the EPC shows a "gasket" on the right, and a "seal ring" on the left to connect the rear muffler. The Worldpac web sites show different "seal rings" for right and left, but they also show a "52mm seal ring." So you obviously need different sizes.