I've had so much pressure to convert my 66 to a dual master I'm considering getting the parts together for the conversion. I may never do it, who knows.
I need info please from anyone with experience.
I will NOT be adding disc brakes to this car, and I will NOT be adding power brakes to this car, strictly a dual cylinder for safety so please don't waste your time trying to talk me into either of those.
What I do need to know is, does a 67 B body drum brake, non-power master cylinder just bolt right into a 66 B body? If so, does the manual trans brake pedal have the pin hole for the pushrod in the correct location for a 67 dual master? Has anyone done this? Also, is the pushrod the same length for a dual cylinder as for the single I have now?
I'm not concerned about the lines/plumbing, I can easily build that.
Thanks in advance.
beaumontguru said
Feb 25, 2021
If its like the chevelles, its pretty easy. you just need all the master and lines and distribution block from a 67. i think i have a block and the lines up to the master cyl for a fullsize pontiac you can have. remind me next time.
You may need to change to a 1/4 inch line going to the rear if yours is 3/16(thats how chevelles are.). and the fittings for the lines are some funky sizes but i have lots of those too, or you can buy them from inlinetube.
beaumontguru said
Feb 25, 2021
Oh, and yes! you should definetly do this conversion if you drive your car more than 5 feet or 5 MPH.
you probably never even noticed i did this on all my 64/65 chevelles and beaumonts,
beaumontguru said
Feb 25, 2021
I did a fulsize conversion on my cousins 65 impala, used all junkyard parts from a 67. I seem to remember there being a large square hole in the firewall that i had to make a small blockoff plate for, other than that i dont recall there being any issues with the pushrods as long as its all manual brakes. his might have had a booster we removed too, and went back to manual brakes, thus the big hole
4SPEED427 said
Feb 25, 2021
beaumontguru wrote:
i think i have a block and the lines up to the master cyl for a fullsize pontiac you can have. remind me next time.
You may need to change to a 1/4 inch line going to the rear if yours is 3/16(thats how chevelles are.). and the fittings for the lines are some funky sizes but i have lots of those too, or you can buy them from inlinetube.
I may have some of those oddball fittings/nuts too and if not I think the dealership has them in an assortment.
I've heard guys say you need to run a 1/4" line to the back. Why is that if the rear cylinders are still the same as they were before?
4SPEED427 said
Feb 25, 2021
beaumontguru wrote:
I did a full size conversion on my cousins 65 impala, used all junkyard parts from a 67.
That should be an identical swap to what I am thinking about doing.
cdnpont said
Feb 25, 2021
You will be using the same manual pedal clevis hole you're using now with the new dual manual master. The bolt spacing should be the same on the master body. Understand that manual masters have the smaller diameter piston. The original 3/16 line to the rear will be fine.
That all I can offer on this,
4SPEED427 said
Feb 25, 2021
Thanks Mark, I actually kind of expected both you and Dave to be a big help on this, and you both are being exactly that!
beaumontguru said
Feb 26, 2021
Ya, was atleast 10 years ago when i did the 65, i know we did change to teh 1/4 line because teh distribution block was that size going to the rear, then changed the rear hose, or actually i think we just got an adapter fitting.
4SPEED427 said
Feb 26, 2021
Those adapters are easy to get so I should be fine. I think I might even have some of them here.
cdnpont said
Feb 26, 2021
The rear line is 3/16 on my 65. Did they go to 1/4 in 66?
What I did was run a new line from the dual master rear, to a female 3/8 inverted flare union onto the old rear line. Just bent the old line upward to meet the new line.
Took that old original T junction, drilled a new bracket bolt hole on the frame, and turned it 90° (on the same axis), blocked what used to be the old right side line outlet and made a new small line to the left brake hose bracket. Used the old right side line as is.
I turned the T block 90°, owing to what was though to be flow issues in its original configuration. You could find a new T that you need not block, but it probably won't have the bracket.
Worked well. And looks fairly factory but for the union in the rear line.
Carl I still have the brake line from the 68 we got the fuel from if you need?
4SPEED427 said
Feb 26, 2021
I'll keep that in mind but I am not so sure I need it. I suspect I can use the existing line to the back. Thanks, I'll let you know. And I don't know if/when I will ever do this. First comes the diff swap, the engine swap, add the rear sway bar etc. And so far in retirement I haven't even worked on my car!
4SPEED427 said
Feb 26, 2021
cdnpont wrote:
The rear line is 3/16 on my 65. Did they go to 1/4 in 66?
What I did was run a new line from the dual master rear, to a female 3/8 inverted flare union onto the old rear line. Just bent the old line upward to meet the new line.
Took that old original T junction, drilled a new bracket bolt hole on the frame, and turned it 90° (on the same axis), blocked what used to be the old right side line outlet and made a new small line to the left brake hose bracket. Used the old right side line as is.
I turned the T block 90°, owing to what was though to be flow issues in its original configuration. You could find a new T that you need not block, but it probably won't have the bracket.
Worked well. And looks fairly factory but for the union in the rear line.
Thanks, I haven't checked yet what I have here but I think I have those pieces. If not, I can get Dorman locally very easy.
One more question, did you retain the cylinder pushrod from the single cylinder or is it the one from the dual setup. I didn't check in the parts book, maybe they are even the same?
cdnpont said
Feb 26, 2021
Mine is power brakes. The booster came with a pushrod on the master side. It was the perfect length, and I did measure it all to be sure. Just a little bit of free clearance, not preloaded.
I think you'll be able to use your existing in car pushrod, provided the new dual master is the same depth as the single line in place now.
4SPEED427 said
Feb 26, 2021
And I'm assuming that rod will have some adjustment in it also.
cdnpont said
Feb 26, 2021
If at the clevis? Then yes, you will have some adjustment for pedal freeplay.
cdnpont said
Feb 26, 2021
Off track a bit, although the description is a little confusing, it looks like Independent front and rear brakes (dual master?) were available in 66 as Chevrolet special equipment.
I've had so much pressure to convert my 66 to a dual master I'm considering getting the parts together for the conversion. I may never do it, who knows.
I need info please from anyone with experience.
I will NOT be adding disc brakes to this car, and I will NOT be adding power brakes to this car, strictly a dual cylinder for safety so please don't waste your time trying to talk me into either of those.
What I do need to know is, does a 67 B body drum brake, non-power master cylinder just bolt right into a 66 B body? If so, does the manual trans brake pedal have the pin hole for the pushrod in the correct location for a 67 dual master? Has anyone done this? Also, is the pushrod the same length for a dual cylinder as for the single I have now?
I'm not concerned about the lines/plumbing, I can easily build that.
Thanks in advance.
If its like the chevelles, its pretty easy. you just need all the master and lines and distribution block from a 67. i think i have a block and the lines up to the master cyl for a fullsize pontiac you can have. remind me next time.
You may need to change to a 1/4 inch line going to the rear if yours is 3/16(thats how chevelles are.). and the fittings for the lines are some funky sizes but i have lots of those too, or you can buy them from inlinetube.
Oh, and yes! you should definetly do this conversion if you drive your car more than 5 feet or 5 MPH.
you probably never even noticed i did this on all my 64/65 chevelles and beaumonts,
I did a fulsize conversion on my cousins 65 impala, used all junkyard parts from a 67. I seem to remember there being a large square hole in the firewall that i had to make a small blockoff plate for, other than that i dont recall there being any issues with the pushrods as long as its all manual brakes. his might have had a booster we removed too, and went back to manual brakes, thus the big hole
___________________________________________________________________________________________________________________________________________________________________________________________________
Good thing you said to remind you! I'll PM you.
I may have some of those oddball fittings/nuts too and if not I think the dealership has them in an assortment.
I've heard guys say you need to run a 1/4" line to the back. Why is that if the rear cylinders are still the same as they were before?
That should be an identical swap to what I am thinking about doing.
You will be using the same manual pedal clevis hole you're using now with the new dual manual master. The bolt spacing should be the same on the master body. Understand that manual masters have the smaller diameter piston. The original 3/16 line to the rear will be fine.
That all I can offer on this,
Thanks Mark, I actually kind of expected both you and Dave to be a big help on this, and you both are being exactly that!
Ya, was atleast 10 years ago when i did the 65, i know we did change to teh 1/4 line because teh distribution block was that size going to the rear, then changed the rear hose, or actually i think we just got an adapter fitting.
The rear line is 3/16 on my 65. Did they go to 1/4 in 66?
What I did was run a new line from the dual master rear, to a female 3/8 inverted flare union onto the old rear line. Just bent the old line upward to meet the new line.
Took that old original T junction, drilled a new bracket bolt hole on the frame, and turned it 90° (on the same axis), blocked what used to be the old right side line outlet and made a new small line to the left brake hose bracket. Used the old right side line as is.
I turned the T block 90°, owing to what was though to be flow issues in its original configuration. You could find a new T that you need not block, but it probably won't have the bracket.
Worked well. And looks fairly factory but for the union in the rear line.
https://canadianponcho.activeboard.com/t66506981/brake-line-t-fitting-question/
That all makes sense except I'm not seeing your right side line in the picture?
If I remember correctly, on the master, the front reservoir is for the rear wheels and vice versa?
No, front is front.
You probably have it well covered Carl, but here's some numbers for the fittings.
I'm using Dorman as they seem to be the most commonly stocked in parts places these days.
3/16 Inverted flare Union. 3/8 thread,
43375
3/16 Inverted Flare Steel Plug. 3/8 thread,
490-490.1
One more question, did you retain the cylinder pushrod from the single cylinder or is it the one from the dual setup. I didn't check in the parts book, maybe they are even the same?
Mine is power brakes. The booster came with a pushrod on the master side. It was the perfect length, and I did measure it all to be sure. Just a little bit of free clearance, not preloaded.
I think you'll be able to use your existing in car pushrod, provided the new dual master is the same depth as the single line in place now.
If at the clevis? Then yes, you will have some adjustment for pedal freeplay.
Off track a bit, although the description is a little confusing, it looks like Independent front and rear brakes (dual master?) were available in 66 as Chevrolet special equipment.