arcee1951

Well, it's time to change the old 66 from a single master to dual cylinder brakes. Has anyone done this? I think the master cylinder is getting a little weak, and I've been putting this off for 45 years.

I guess everything was fine, when it had a 6 popper in it but engine changes, tranny upgrades and rear end changes make this a little quicker than before, and I'd hate to wreck it, after all these years.

I'll need
a dual master cylinder
brake lines (better to order or make my own?
proportioning valve- is this needed?

What else?

Thanks, all.

joe_padavano

No. No one has ever done this. You would be the first...

Seriously, Oldsmobile did it in 1967. All you need are the parts from a 67 and it all bolts up.

Only if you have disc brakes. Once again, drum brakes do NOT use a proportioning valve. The distribution block that has the differential pressure switch for the BRAKE light on the dash is NOT a proportioning valve and is not needed if you don't have a BRAKE light or care about being told you have a brake leak shortly after your foot goes all the way to the floor.

Run to Rund

I got a Centric master cylinder from John Andreotti at Ott's Friction Supply. Plumbed the rear line directly to the master cylinder, same for the front line, to a T, and then to the front brakes. Get a pushrod retainer cup from Inline Tube so the pushrod can't fall out. The repro cup or derby hat is INL 12439.

joe_padavano

If you have power brakes, you don't need the pushrod retainer, but you do need either a 1967-72 booster or to retrofit the shorter pushrod between the booster and M/C. The long pushrod in the stock 66 booster won't work with a dual circuit M/C.

arcee1951

Thanks, guys. These will be manual brakes, for now. Right now, I have one line coming from the master cylinder to a block below. This block has 3 holes, so it feeds the front and rear brakes from one cylinder.

Run to Rund, if I just make a union with the current rear brake line, and run that directly to the master cylinder, I'll have an extra hole in the block. Do you say that it is safe just to put a plug in that extra hole that was leading to the rear brakes?

Also, would it be safe to make up some kind of union to get the rear brake line to the master cylinder, without replacing the whole brake line?

Thanks, all.

Run to Rund

You can remove the rear line at the junction block, get a union and run that 1/4" line to the rear master cylinder port. You could plug that position of the junction block with a special plug that you can buy at the NAPA etc. Run the line coming from the single master cylinder into the front port of the new master cylinder. That line goes to the junction block and then to the two front brakes.

Octania

Interesting....
I never considered doing this w/o the junction block/ brake light switch block...
If you have no brake light, the switch does little.

Joe, as usual nails it - "if you don't care about being told you have a brake leak shortly after your foot goes all the way to the floor"

priceless

arcee1951

Ahso, much humor Octaniasohn and Joesohn. I'm going to try to bleed them today. The car has been sitting in a heated garage for over a year, now. I'm hoping to bleed them, and have that work until winter, then make the changeover. I don't see any leaks at any of the cylinders or master, so maybe I'll get lucky. I do want to take it to Kool Deadwood Nights, in the Black Hills again. I must admit that mountainous driving is a little spooky with these brakes.

Thanks, again, all.

MDchanic

A man after my own heart.

- Eric

arcee1951

Well, I was hoping to wait to change the master cylinder, until I park the car for the winter, but while cruising down the main drag, the brakes went to the floor. I was lucky enough to downshift to low, and slam on the emergency brake to keep from kissing the rear end of a Ford 150. Those back brakes sure squealed and scared the guy in the truck, at the stop light.

So, I was going to go down and pick up the master cylinder from the 67, that I ordered, and thought I'd removed my single pot, as they would take that as a core for the dual pot.

I got the lines and nuts off the master cylinder, but do I need to remove the rod from the brake pedal? Also, this rod will not work on my new master cylinder?

Note that I'm just keeping the manual brakes, so no power booster is involved.

Thanks.

arcee1951

Hmm, I'll try again. I tried to go to Inline Tube for the push rod retainer, but they didn't have it. I can't find any 67 Oldsmobiles around this area. What ideas can you guys give me on finishing the job It doesn't look like the push rod from the single stage will work on the upgrade dual pot master cylinder. The old MC has a retainer C clip to hold the rod in place. Do I need to manufacture parts? Thanks.

joe_padavano

Fortunately, first gen Camaros use the same retainer, and you can get EVERYTHING for a first gen Camaro...

http://www.camarocentral.com/1967_19.../brc-1007e.htm

arcee1951

Thanks, Joe. Just to be sure, do I need to change the rod from the peddle to the dual pot master cylinder? If so, will the Camaro rod work? I had a few physical problems, but need to get the old girl going again.

joe_padavano

The pushrod for the dual M/C is shorter than for the single M/C. I do not know if the Camaro pushrod is the same as for an A-body, however. The pedals are different.

lemoldsnut

If you choose to I can provide everything from a 67 in one package

contact me direct at lemoldsnut@aol.com

or calls west coast time 8 am to 8 pm 541-815-4363

Thanks
Larry