Vistabrat72

Good evening to the forum. In the interest of safety on the crowded roads going too and from classic car shows, we decided to have our 1966 Olds Ninety Eight converted from a single to a dual master cylinder setup. Thanks to Joe Padavano for saying it was not simply swapping in a 1967 and up master cylinder, due to push rod lengths. And what cylinder should be used, but not proven yet in the field. I am happy to say the suggested 1966 Cadillac master cylinder (Cadillac switched to a dual master cylinder in 1962) fit like a glove, and we now have a dual braking system on our car. Then original lines on the car are in new shape and were able to be bent to fit the new cylinder, the shop only needed a 6-inch extension to complete the circuit to the rear brakes. I know it does not look factory squeaky clean, but safety is a priority. The part number for the cylinder is M36373, from a company called Pronto. Dorman seems to have the same number too. I hope this helps to save many headaches from happening to those wishing to switch with minimal fuss.


The new dual master cylinder part number M36373

D. Yaros

Good info! Am curious, did this dual MC require a different push rod?

joe_padavano

It should not. The early Caddy dual M/C had a deep pushrod hole in the rear piston that accepts the long booster pushrod.

Vistabrat72

Thank you D. Yaros, I hope this helps others. Proof positive what Joe said, it was a perfect fit. I did notice when we did a quick trial fit before we took the car to the garage (We were able to move the original cylinder forward, attached to the line, out of the way) my push rod is the adjustable type. Nothing had to be altered or readjusted.

D. Yaros

Joe P. - So, the question for me becomes: Will the 62 Caddy dual MC bolt up and work without other mods on my 1962 Olds Dynamic 88?

joe_padavano

Yes, the Caddy M/C has the deep hole needed for the long pushrod on the 62 booster. Note that the Caddy M/C has outlet ports on the passenger side, but you'll need to replumb anyway, so that shouldn't be a big deal. And the P/N is the same for 1962-66. It's a 1" bore M/C.

D. Yaros

I thank you. Pleased to have this info. Have searched the web and found that the 1962 Cad MC is readily available at reasonable cost.

6262

Does the '62 to '66 Cadillac dual circuit master cylinder also fit the '60 Oldsmobile Dynamic 88?

Thanks!

joe_padavano

Unfortunately not. The piston for the master cylinder is integral with the booster on your car. You cannot retrofit a different M/C to that booster. You'll need to change both booster and M/C.

6262

Okay, thanks for the quick answer. Is there any master/booster combination that "plugs right in" (lines exempted)?

Charlie Jones

It will if it's a Moraine cylinder . (2 bolts)
It won't if it's a Bendix . (4 bolts)

6262

Thank you, Charlie!

Is this also true for the '60 Dynamic 88?

Charlie Jones

No , 1953 thru 1960 Oldsmobiles with power brakes , had a Treadle-Vac booster and master cylinder unit .
They mounted under the floor and were quite different from conventional "pendilum pedal " setups on later cars .
These cars have been successfully converted to "modern" dual-master setups . As evidenced by this thread here ;
https://classicoldsmobile.com/forums...1955-olds.html
It all depends on your fabrication skills or the depth of your pockets .

6262

Thanks for sharing your knowledge. Very helpful!