1970 Cutlass Master Cylinder/Power Booster mismatch

[Guest]

Hello all,<P>I purchased the aforementioned 1970 Cutlass two months ago. I was not happy with the braking, and found out that my master cylinder had leaked and the rear reservoir was dry. I refilled today and bled the brakes and loved it! I knew I had to get a new MC, though.<P>I went to AutoZone and bought a new one. The problem is that the old MC has a depression over an inch deep for the pushrod, while the new one (and every other one there for any type of 1970 Cutlass) has only a dimple. See <A HREF="http://1970cutlass.homestead.com/Photo_Gallery.html" TARGET=_blank>master cylinder pictures</A><P>There is no way I can use this MC with my current booster and pushrod - it won't even bolt in place. The car has front discs and power brakes. I don't know if it originally came this way in 1970, though. Can anyone tell me which pieces I need to swap on the car to make it work?<P>Thanks,<BR>Patrick

[rocketraider]

You've gotten into a common bugaboo on early 70s Oldsmobiles, though I see it more on the big cars- the difference between a Moraine and a Bendix power booster/master cylinder set. AutoZone is giving you the right M/C for the car. Matter of fact, the Olds factory parts book only lists a Moraine booster and cylinder for 1970 F85 cars, which has the shallow recess you describe. Don't know how the Bendix unit with the deep recess got on there unless the booster/MC assembly was replaced at some point with a wrong year part.<P>Go to a NAPA or CarQuest that has someone who knows how to use a parts book and not a computer. They'll come closer to getting what you need. You may end up having to change out the whole shebang- booster, M/C and all.

[Guest]

Thanks!<P>In dong some research yesterday, I think what I've got is the original booster (or at least original configuration) with incorrect pushrod and MC.<P>My plan had been to restore the booster and replace the MC this winter. I've just accelerated the process. I've got a restored booster coming now from Steve Gregori with the correct pushrod, and I'll keep this new MC.<P>Any idea what the correct Delco casting number would be for my car? I'd like to find an original if possible and have that redone for the car.