Gasket between MC and booster

JHZR2

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I think I found my new least favorite routine maintenance.

The pre and main filter on my Dodge Ram Cummins is next to impossible. It’s a spin on for the 94-96 my, and buried way deep. Too many things in the way to get it from the top; and on the ground, at least laying on my back, it’s too high. Massive opportunity to get beat up by your truck, and get dirt in the main filter.

So then I read that you can unbolt the Master Cylinder. I guess the lines are long enough that you can push it to the side a bit. So I might do that just to at least clean things up a bit and work on the water in fuel connector that did not want to go together.

Is there a gasket between the MC and booster? Is it a replacement item? I assume there should be one because there is vacuum in there. Do these gaskets typically degrade if they have been kept free of brake fluid? Should I preemptively replace if separating the two items?

Ive changed probably 30 pre and main filters on MB cars. Easy. This thing was not.

And it was good to do...
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Yes there is a gasket behind the master cylinder that sets on the brake booster usually it’s paper. I haven’t ever replaced one I just use the old one over but it probably wouldn’t hurt to replace it. I think your picture is pointing to the inside which usually does not have a gasket from what I have seen.
 
Yes there is a gasket behind the master cylinder that sets on the brake booster usually it’s paper. I haven’t ever replaced one I just use the old one over but it probably wouldn’t hurt to replace it. I think your picture is pointing to the inside which usually does not have a gasket from what I have seen.

OK, so it’s generally reusable... that’s good news! It’s just applied dry? Or is it glued to one side or the other?
 
I am pretty sure the vacuum only is in the inside of the booster and has nothing to do with the area behind the booster. The area between the booster and the break master cylinder has nothing going on with vacuum, and the only thing going on in that area is the mechanical connection between the two. The only thing to be concerned about is that the connection between the two does not let dirt in, and that mechanically it is secure because the booster does apply pressure to the master cylinder and if the bolts holding the two together failed the booster would not supply any boost.
 
Looks to be a lathe cut seal, Clean it up & you'll likely be okay. However.....Those Cummins 6BT vacuum pumps don't like vacuum leaks! It can cause engine oil usage. If you have access to a smoke machine....Smoke the vacuum circuit!!
 
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