NEW power brake booster?

[L05edSS]

It also depends on what you need. Monte Carlo for some reason could have either a single diaphragm or dual diaphragm booster. I've done no research as to what triggered which RPO. Check the SPID for JM5 (dual) or JM7 (single).

Well, if you DO happen run across an NOS one and you have JM5 dual diaphragm, the p/n's you'd be looking for would be:

18010065- original equipment number until mid-1983
18010120- original equipment for the rest of the G-body run
18060040
19208172

Last ones were made about 25 years ago, so there's that. For Oldsmobiles I know, up through 1984, they were gold cad plated, then, best I can tell, starting in 1985, they were painted black and all used the above numbers. Generally speaking. I've not seen every 1984 Cutlass ever made, so I don't know for sure exactly when they swapped over to painting vs plating. They did a lot of running changes back then.

For the single diaphragm (JM7), look for these numbers, from oldest to newest:

18005853- original equipment number for all production
18010113
18015333
18060109- Discontinued nearly 30 years ago.

TBH, I don't know why you couldn't use either/or with the boosters as long as everything hooked up properly. They used the same master cylinder. Did it have something to do with physical clearances? I dunno.

never thought could be so complex so napa looks best way to go. cant imagine what the gn/ gnx guys have to go thru with these parts

 

[565bbchevy]

As far as clearance issues on my 83' Monte my stock 9" dual clears my BBC without issues where the single would be a problem.

 

[Sweet_Johnny]

I paid Rock Auto $70 for a new 9" double diaphragm unit for an '85 Monte from SKP: SK5471243.

It's going into a '78 Cutlass but hasn't been installed yet.