Anybody switched to a dual reservoir master cylinder?

I purchased the rare-as-hens-teeth Bendix style booster from RockAuto. They showed they had two. NAPA, AutoZone, O'Rielly, and Advance can't get them, so it should be fun if I ever need to warranty it. It probably would have been easier to go matched Delco/Delco, but I was drawn to the Bendix and that's what I decided on.

 

Sounds like your all set then! Finding the booster really was the most difficult part. I lucked out and just happened to find a Delco unit from Cardone.

 

Found this thread while google searching on this exact topic. Lead me to join the forum so may as well bring this back.
I have a 62 lesabre with manual drums. It has the wrong single master on it. I'm looking to replace it although finding a 62 master is difficult so Id like to put a dual on it for safety reasons too. Anyways, my difficulty is finding out if the manual master is the same unit as the power assist master cylinder. I can't seem to find that answer.

 

If there is any difference, it would be in the pedal push rod, which is the part that contacts the master cylinder piston. The replacement dual reservoir master cylinders come in a shallow bore (for a short push rod, Delco booster style), and a deep bore (for a long push rod, Bendix booster style) configuration. If you pull off your existing master cylinder, it should be relatively obvious which master cylinder you would need. Best of luck! :beers2:

 

The push rod length is my issue. The problem I'm having is that my brake lights come on and stay on after driving. If I pull the brake pedal back by hand the lights can turn off. Making me believe the master I have on there is incorrect, not to mention the threaded end for the brake light switch is the wrong size.

I would like to replace it with a dual, but without playing a matching game, was hoping it's been done by someone on here or somewhere already.

My other option is to just pull the trigger and buy a dual for a 67 buick with drums and see where it takes me.

My

 

The brake lights are activated by a pressure switch. Unless someone replaced your brake pedal assembly with a later unit, where the switch is activated by pedal position, I'd suspect a faulty or sticky switch. Even if you can pull the pedal back some, just resting there shouldn't cause enough pressure to activate the lights.

I cannot say enough how important it is to upgrade to a dual reservoir master. I always had the mentality that a single reservoir was fine, until I lost my brakes while trying to slow from 60mph at a stop light. Not fun!

 

I did replace the brake switch hoping that May have been the problem. Here's a picture of the current one I have, notice the adaptors because the threaded end is incorrect. I believe that is actually for a 62-66 Chevy full size.

 

Guys, I did this on my '61 Electra 4 door: I bought a dual res. master, and booster from a 1985 Monte Carlo! I of course had to do the re-route of tubing that has been described earlier in this thread, but with the use of tubing adapters, as others have, it works really well. The studs that go through the firewall were just slightly off, so I used a rat tail file to modify them a tiny bit, and it bolted up perfect. Also, as a bonus, the rod hooked up to the pedal without modification. I am super happy with this, and use the stock 4 wheel drums, aluminum up front. This stops like a champ, too! I replaced the wheel cylinders while I was at it, as well as the brake shoes, and had the drums turned. Simply awesome brakes. ---------Metalguy

 

If it's any help, here is the one from my '61 LeSabre:



This is a replacement, but as I recall, the original was the same except for the cap.

 

Interesting yours has four bolts to mount it to the firewall. I've always seen 2 bolts for GM master cylinders since forever, errr since after 61 lol

 

So little update on mine, I got the "correct" buick master cylinder on a month or so ago and while it worked the pedal was low and weak. I also noticed my rear drums were hot after driving. So last week I tore the rear apart and replaced the trashed rear brakes, wheel cylinders and wheel seals, shoes and hardware. Now I have NO pedal, straight to the floor basically, no pedal until the last inch. I'm replacing the rear rubber hose this week but have a feeling this expensive "correct" master cylinder is not right.
If that is the case I'm going to try my luck with a dual set up and will try the master cyl Cameo purchased from the Zone. I'll keep you updated on this!

 

My vote is to switch to a dual reservoir. I was always the guy that thought they weren't needed, until the pedal hit the floor while doing 60mph and heading towards a stop light. Talk about a pucker factor!

 

I don't know what the deal with these brakes have been, the vehicle has been Not drivable more than drivable the last year I've owned it because the brakes were in such bad shape.
The dual is so cheap and since I'm not changing anything I can risk the dual master not working.

 

Morning all. So I ordered the dual master for a 67+ buick with drums, however i remember why I didn't pursue this more back last fall.... The master cylinder on my car currently has the pedal pushrod C-Clipped to the master, these dual ones do not do that. I'm guessing the rod just rests in the back of the piston?
Anyways, I haven't given up, I'm looking for an adjustable one. With the eyelet on it so that it hooks to the pedal assembly like factory setup. If anyone knows of one that's not super pricey let me know.

 

Yes, the push rod rests against the back of the master cylinder piston in a recess. Also be aware, there are short and long bore master cylinders, where the push rod goes. One is meant for a Delco booster, the other is meant for a Bendix booster. I'm not sure which was used in the manual brake applications.

 

That's the problem CameoInvicta, since no one lists a master as being for manual brakes, I'm going by what my single has, which is a shallow bore. However the pushrod is attached to my single master. And not on this dual.

 

CameoInvicta where did you find this adapter for the brake light switch? I cant seem to find one, and its holding me back from finishing this haha ray:

 

I either got it from Napa or Ace Hardware. Should be a female 3/16" inverted flare to female 1/8" NPT. I'll double check when I get home this evening.

 

http://www.amazon.com/Allstar-Performance-ALL50127-NPT-Adapter/dp/B003C01DB0

I think I might have found one, but if you could check that would be great!

I thought I found what I needed. but when i went to order it realized it was 1/8" MALE to 3/16" FEMALE, backwards what I needed, whoops. Parts searching after having a few fail. :beer

 

That looks correct! Jegs has it minutely cheaper, just FYI. I'll still check when I get home.