I've been scouring Lionel's site to no avail, trying to find a good part number for a brake hatch on my 6-8357 Pennsy GP-9, I found some on the interweb that are gray and black, but I need that Pennsy green.
Does Lionel carry MPC parts or not? I thought they did/do, but no joy on this one - no brake hatch, user's manual, parts list, etc.
Generally speaking, the dynamic brake housing on the early MPC Geeps was painted as a unit with the body. Therefore the correctly-colored hatch was never available as a separate part, nor was it given a part number. Your only options are to find one removed from an identical Geep, or as mentioned above, paint one yourself.
Lionel does carry MPC parts, while supplies still last. Remember that the newest MPC items are now 32 years old, and that your 6-8357 turns 45 next year.
The correct instruction sheet for your 6-8357 is a 70-8352-250.
A 1992 revision of the original parts list can be found here:
https://www.lionelsupport.com/...ts/18030Complete.pdf
I hope this helps.
TRW