Vintage Mustang Forums banner

1 - 16 of 16 Posts
G

·
Guest
Joined
·
0 Posts
Discussion Starter #1
I recently installed a power brake booster on my 66 convertible. The car has drum brakes all around. I have no desire to switch to disk brakes or a dual master cylinder. The trouble I am having is that the brakes are really hard to push. The throw is much shorter than when I had manual, but much harder to push. They are easier to hold down when at a stop though. The guy who installed them (I am sort of a rookie) teed off an existing vacuum line rather than going straight into the manifold. He said it should not matter. He also said that they won't be as easy to push as my other cars (88 Acura, 99 Dodge). I understand that, but they should be better than they are.

Does anyone have any ideas as to why I am having this problem, and what I can do?

Thanks from the new guy.
 

·
Registered
Joined
·
5,527 Posts
The power brakes won't feel like the modern ones.

Did you have the power brake pedal installed at the same time? They are different.

Pull the vacuum line and check to see that it has vacuum. You might even measure it with a guage. See if it makes any difference in pedal feel when you pull the line.


Coppertone's current condition:
http://www.knology.net/~dorner/images/coppertone2.jpg
 

·
Registered
Joined
·
21,010 Posts
Who's kit did you use? you might want to check with the manufacterer to see if this is right. Usually power drums can be very sensative, I thick I would check out that vacuum line, Is it the size it should be? I don't know any other vacuum line off hand, on the 66 that would be as large as the booster line that could be used. Maybe the line is too small and is collapsing.

Tom
You can do anything you want to......ONCE!
aka "my 66 coupe"
http://albums.photopoint.com/j/View?u=1575517&a=11977890&p=44194856.jpg

Hale Boppe comet shot off my roof. See you can use 100 iso at night with no flash!
 

·
Registered
Joined
·
652 Posts
If your guy didn't replace the brake pedal itself, then the job isn't done yet.
The geometry of the pedal-to-master cylinder is different for power vs. manual
brakes. I'm in the process of doing this conversion myself, and I don't know the
specifics of the pedal differences (but I'm DYING to know what they are if anyone
else here knows).

Please post any solutions you come up with on this problem.

Rich
'67 C-code 'vert (Dees67)
'69 GT FB (project car)
Check out my band: Brickyard Blues
 
G

·
Guest
Joined
·
0 Posts
Discussion Starter #5
I used the same pedal. I did not think there was a different one for a 66. How is it different? I did check for vacuum, and there is some, but I don't know if it enough. What should the gauge read? I will try pulling the line and see what happens.

Thanks
 
G

·
Guest
Joined
·
0 Posts
Discussion Starter #6
I didn't use a kit. I got the booster and master cylinder off ebay for a very good price. I rebuilt the ms and my mechanic installed. He did have to rig the pedal a bit to get it to fit. I did notice that the vacuum line that he teed into was smaller and very filmsey. It may be collapsing. I will check that.

Thanks
 
G

·
Guest
Joined
·
0 Posts
Discussion Starter #7
I have yet to find a brake pedal just for 66 power drum. It appears that all 66 drum auto trans are the same. If you find a place to get the right pedal, let me know.

Thanks
 

·
Registered
Joined
·
5,527 Posts
The power brake pedal has this elbow thingy that makes the pedal height different, and maybe changes the way the plunger moves. I would suspect this is the main problem. If the pedal is binding in any way, it would sure create problems.

I'm not sure what the vacuum should read. Maybe the manual covers it.


Coppertone's current condition:
http://www.knology.net/~dorner/images/coppertone2.jpg
 

·
Registered
Joined
·
5,527 Posts
The Paddock catalog talks about changing from manual to power. It says, "change the brake lines, valves, brackets and, in some cases, the brake pedal." "Bolting a power brake booster on your car will not change your car to power brakes." They are also selling the elusive bracket for $159. The part number is 1512BCA. You might check the classifieds for the parts.


Coppertone's current condition:
http://www.knology.net/~dorner/images/coppertone2.jpg
 

·
Banned
Joined
·
4,577 Posts
I will be doing the same conversion this summer, and just like you with original ford parts. I've been told that the non-power brake pedal can be used, but it will fade closer to the floor than what a power brake pedal would. Did you change out your master cylinder as well? I know you need the M/C for power brakes. I'm not sure what the difference is, but I heard the bore is different. Also, did you replace the check valve on the booster as well. Some rebuilders don't include new ones on rebuilt boosters.

Here's a few photos of the Power brake pedal for a 66, I hope this might help some.

http://members.spree.com/entertainment/whizco/miscphotos/mvc-826s.jpg
http://members.spree.com/entertainment/whizco/miscphotos/mvc-827s.jpg
http://members.spree.com/entertainment/whizco/miscphotos/mvc-828s.jpg
http://members.spree.com/entertainment/whizco/miscphotos/mvc-829s.jpg

Doug

[color:red]VMF Exchange Board</font color=red>
http://members.spree.com/entertainment/whizco/owner/dwhisenant/66tl2.jpg
[color:blue]My Mustang is Camera Shy</font color=blue>/forums/images/icons/blush.gif
 

·
Registered
Joined
·
3,179 Posts
Doug, have you compared them side by side? Call me a Doofus but that power brake pedal looks very close to what a non-power brake pedal looks like. 'Course I can't find any of my extra pedals to make a better comparison than the modified unit on the Garage Shelf.

Great visual aide!

Dean T

Shikatta Ga Nai - "It cannot be helped"
 

·
Banned
Joined
·
4,577 Posts
Yea I sure have, and as you stated they look almost identical. Of course the non-powered brake pedal is still on my 66, so I could lay them next to each other, but after I placed the powered pedal next to the non powered pedal, I saw that the angle on the power pedal was higher. As for now, that is the only comparison I am able to do.

Doug

[color:red]VMF Exchange Board</font color=red>
http://members.spree.com/entertainment/whizco/owner/dwhisenant/66tl2.jpg
[color:blue]My Mustang is Camera Shy</font color=blue>/forums/images/icons/blush.gif
 

·
Registered
Joined
·
271 Posts
1. 1967 was the first year which used a different power/manual brake pedal. 1965 & 1966 cars had only four pedal types to choose from, depending on whether the car had Auto or Manual transmission, and Disc or Drum brakes.
2. The '65-'66 power brakes have a very short travel, but the excessively high pedal effort is probably due (at least in part) to insufficient vacuum.
3. Doug's pedal is actually from a '65 (or very early '66 carryover) -- that external rubber stop and associated mounting arm were replaced by a far more cost-effective pushrod retaining clip within the manual master cylinder and was entirely superfluous on the power brake-equipped cars anyway.
 
G

·
Guest
Joined
·
0 Posts
Discussion Starter #14
Whizco,

The Booster I purchased came with the master cylinder attached. I rebuit the ms with a rebuild kit from NAPA for $15. I rehoned the inside as well. The check valve appears to be fine, but I am going to replace the rubber gasket that holds it to the booster, it is a little worn. Thanks for the great photos. I will have to climb under the dash to see mine. I know my mechanic had to be a little inventive to make the connection, but he did it.
 

·
Registered
Joined
·
1 Posts
power brakes on a 66 mustang

your need to get a BRAKE VACUUM CANISTER / RESERVOIR POWER BRAKES
your not getting the vacuum that the buster needs i know because i just install a power brake booster on my 1966 mustang 289 do you have a bigger cam in the eng if so your need to get the BRAKE VACUUM CANISTER / RESERVOIR POWER BRAKES this will fix it
 

·
Registered
Joined
·
1,588 Posts
1 - 16 of 16 Posts
Top