1973 Oldsmobile Delta 88 convertible

I would almost bet with the paint crazing that’s a long time ago repair that is letting go in that the paint next to the missing part is checked and also showing movement and additional signs of letting go of the bond with the metal underneath. It would be interesting to here what you paint guy says.

 

I showed Hubby your pictures, he says yes your master cylinder is likely original and correct for this size of car. The rear cylinder is for the back brakes and if it is low it should be topped up. But he suggested that you might want to drain the lines and add fresh fluid. The front cylinder is for the front brakes and is bigger then the rear cylinder. Hope that helps.
Great looking car you have there. It looks good between Red Toro and White Toro.

 

She's certainly the Belle of the Ball.

 

Thanks for all the info. I suspected it is original. Regarding replacing the brake fluid, I plan to actually re-do the brakes from stem to stern with new master cylinder, vacuum booster, rear shoes and wheel cylinders, hoses where needed, and new pads and perhaps calipers up front. All of this will certainly drain the lines nad require all new fluid.

The rear reservoir on the MC was low, and I added fluid just to drive the car around as needed. The brakes do stop the car fine right now and the pedal is firm. I hope it's still that way when I'm done!

 

It will be, but of course, a stem-to-stern inspection of the hard lines front and rear would be a good idea. I've almost always found that GM and Ford hard lines resist corrosion pretty well when not exposed to road salt.

 

I went to a car show recently and saw about 100+ gm cars from the 70's. I thought of you when I was looking for the master cylinder. Non of them had this style of master cylinder.

I did see it on many 60's Gm cars though. Sorry, not original.

 

The front-drive aspect of the Toronado probably means a different master cylinder design, with a larger front reservoir, due to have a more forward weight bias. It's probably identical to the master cylinder found on the front-drive Eldorados.

 

Actually, it does not. When I went to buy a new MC for the '73, it turned out to be the same part number as I purchased for my '77 and '78 Toros. These MCs commonly have a larger front reservoir than rear reservoir because it's the front brakes that do most of the work in stopping a car whether front drive or rear drive.

 

Here's the new master cylinder on the car. I had to reuse the original brake booster, which does work, because I have been unable to find a correct replacement. I hope this one never gives out!





For comparison, here's the MC (and a new booster, which IS available for this car) on the '78 Toronado. The MCs are the same.

 

as long as the booster holds vacuum with the car not running I expect it will go quite some time. Those factory boosters seem to last.

 

Yeah, they really only fail when the master fails and lets fluid in and the rubber diaphragm fails.

You can get your original rebuilt, but that's about it for the smaller style booster.