[Sloan66]

I posted this in suspension section did not get much feedback,I have factory PB on my 66. Recently the pedal has changed. The pedal itself has moved closer to floor and when I press the brakes while driving they seem not as firm. The brakes also seem to drag as they generate a lot of heat, I adjusted them checked the hardware installed correctly, drove and soon they began to drag again. When i pump the pedal with engine off and then hold and start the car the pedal moves ever so slightly. Any thoughts?

[Old Blue 66]

Well, yo have think its somewhere in the booster or the master. I would tend to think you have a bad master. Is it a single or a duel?

[Sloan66]

It is a single.

[Old Blue 66]

Maybe someone else will chime in but its my opinion that it sounds like the master. And with a single master, you cant be too careful.

They are cheap and easy to replace. If you don't know how old it is, Id replace it regardless. My opinion

[GT182]

Better off to change over to the dual master cylinder. Pontiac smartened up and did for 67.

I had a rear brake line fail on my 66 and it was a bitch to stop. Thank God I had the 4 speed. When I go to front disc brakes the single will be changed to a dual.

[Jeff Hamlin]

Are you losing fluid?
If not then the Booster is likely your issue, check your vacuum/connections.

I have the factory power drum single reservoir on my '66 and keep it all in good order with no issues during hard braking,
Yes the dual res is a good idea but not really necessary if all is in order.

[Andre]

My guess is thar your rubber line is collapsing on the inside but not visible from the outside. Probably the one on the rear. If it was one on the front, the car would pull to one side.

[Sloan66]

Thanks for the feedback, I will check those items. All the rubber lines are new, the master is the original which I rebuilt.

[Sloan66]

It is the master cylinder, who makes one close to the original configuration?

[GT182]

They only thing is Jeff.... you never know when a hard line will fail, or when a rubber line at the wheel will fail. Any day of the week I'd rather trust a dual master than a single. Just my

[Old Blue 66]

Originally Posted by Sloan66

It is the master cylinder, who makes one close to the original configuration?

I think our host sells one.

[Jeff Hamlin]

Originally Posted by GT182

They only thing is Jeff.... you never know when a hard line will fail, or when a rubber line at the wheel will fail. Any day of the week I'd rather trust a dual master than a single. Just my

That's why my '66 is a stick On the edge!

Rock Auto has several listed;
http://www.rockauto.com/catalog/more...415&cc=1350155

[fyrffytr1]

Go to your local parts store. O'reilly's carries them or can have one the next day if it is not in stock.
http://www.oreillyauto.com/site/c/se...est&vi=1493460
If you want to go with a dual you can get one of these but, remember you will have to add lines and a distribution block.
http://www.oreillyauto.com/site/c/se...GTO&vi=5152716

[GT182]

Jeff, mine is a stick too. But that doesn't make you stop.... slow down to a crawl yes, but brakes make you come to a full stop. Only one thing scarrier than the GTO not stopping and that's a big rig with no brakes. I've had both happen and I don't care for either situation, or poop in my pants.

And I know why Old Goat 67 has hydroboost.

[Old Blue 66]

The year was 2004. The event was the 40th anniv of the GTO at the GTOAA Nationals in Detroit. I was with some friends and their cars cruising down Woorward Ave in a caravan with my blue 66. The brake pedal started to go slowly to the floor and they went out. Almost rear ended my friend who is 20 years older than me driving the GTO he bought in high school.

We called around all over the place and nobody had a single master in stock. Last resort was the local Pontiac dealer in Detroit. Luck!!! They had one for my car. Within a couple of hours they brought out a fully loaded master ready to put in my car. The mechanic installed it without even asking me. And when it was time to leave, he didnt want any money. He said "Im lucky enough to come here and see all the cars, this ones on me".

True story.

Back to topic.

[george kujanski]

Anyone with a single master should change to a dual. Don't take a chance. It could save your car, your life, or someone else's. For the cost of a master and a distribution block, it's cheap insurance.

Over the years I've had brakes fail on one circuit, it's scary enuf when it still stops with the pedal quite a bit lower to the floor.

George

[Satyr1966]

I've changed one of my '66 GTOs over to a dual master cylinder. I used a '67 master cylinder & a '67 brake booster. Has anyone used a '67 dual master cylinder on a smaller '66 Booster? Just wondering because I'm going to be doing this on my Son's '66 & I don't want to have to get the bigger '67 booster if it's not necessary.

[gtos4ever]

Originally Posted by GT182

Better off to change over to the dual master cylinder. Pontiac smartened up and did for 67.

It wasn't that Pontiac smartened up but rather a Federal mandate, along with the 4way flashers, seat belts, and energy absorbing steering column.

[GT182]

Originally Posted by gtos4ever

It wasn't that Pontiac smartened up but rather a Federal mandate, along with the 4way flashers, seat belts, and energy absorbing steering column.

True as stated. But... 66 GTOs had the option for the 4way flasher and shoulder belts before the mandate. My first 66 GTO had shoulder belts in it from the factory and the 4 way flasher unit too. I'm probably wrong but wasn't 66 the first year for these 2 options? I've never seen a 65 with either one installed. And the Restoration Guide says nothing about 4 ways until 67..... nor does the 66 Service manual as far as I could see.

[fred kobbe]

Originally Posted by Sloan66

It is the master cylinder, who makes one close to the original configuration?

hi sloan 66
read all of the responses to your problem and yes they are all very good possibilities
when we restored my 66 goat I put a chrome dual master and a chrome booster so I have a cast dual master and a gold booster with proportioning valve. this master was orginal and we rebuilt it worked well on the goat, if you should to decide to go dual I have a complete unit that we can deal on
if interested e/m meat alk3928@hotmail.com
Good luck