Master cylinder rebuilt kit not 100% the same

[Johny5]

I'm in the process of redoing all of the brakes on my M35A2.

I picked up a rebuild kit and I noticed a few differences and wanted to get some input.

The seal at the very back is slightly smaller and doesn't fit in snug like the old seal. I went ahead and rebuilt it with the new seal seeing the force isn't on the outer edge of the gasket but the disk of the gasket. I do not think it will be a problem but I always look for other peoples input as they may have done this once or twice and seen some things.

I have not installed the master cylinder back into the truck, as I am going to rebuild the air pak tomorrow and still need to do all 6 wheel cylinders.

Also the seal is different on the plunger, just found that interesting.

 

[texas30cal]

Has anyone else seen this? I've just experienced the same thing, MC had a small leak so we rebuilt using this same kit. We pressure bled the system starting with the MC then the air pack . When we bleed it the pedal gets nice and hard and the travel is the same as before with air pressure built up, but after depressing it a few times it goes to the floor.

 

[Johny5]

I still haven't gotten everything back together yet, so I'm not 100% sure if the kit fixed it. My airpack was a wreck and I'm still working on that, plus all my wheel cylinders. I just haven't had any time to finish this project yet.