My brakes have been pretty terrible ever since i bought the car about 4 years ago. I guess i can't expect much from manual 4 wheel drums haha. What is interesting though is i cannot get the "brake" light on the dash to go out. Upon further reading in the Service manual i have for the car, it says that when the proportioning valve is not centered, the light will come on. So i have tried numerous times to centralize the valve with no success. I think the valve may be stuck. The main problem i am having with the brakes is that it likes to dive to different sides when the brakes are applied. Sometimes it will stay straight and stop, other times it will dive to the left, then the next time i hit the brake it will go to the right. And it also seems that if i apply more pressure, the car will try to straighten itself out. i have replaced the slave cylinders at all 4 corners along with new pads and hardware. Maybe this isn't a problem with the valve but i figured this is the only thing that is old and hasn't been replaced. So i figured i would just buy a new valve, well everywhere i look, everyone is selling valves for disc-disc applications. No 4 wheel drum application. Would it matter whether its drum or disc? Has anyone else had any luck with another valve or some other setup? Sorry for the long post, i am pretty stumped and new to all of this. Thanks in advance. Oh also the pads are all on correctly.. also checked on that a few times as well.

 

Try NPD or Mustangs Plus ??

 

The erratic braking is pretty much normal for front drums. I'd recommend cleaning, servicing, and adjusting them, which will likely help, but it's almost impossible to keep the car braking in a perfect straight line all the time unless you adjust the brakes every time you drive the car.

The 'valve' you're talking about isn't really a valve, it's just a pressure differential switch in the distribution block mounted on the d-side fender near the master cylinder. When one side of the brake system (front/rear) has less pressure than the other, the switch moves and trips the electric switch that turns the dash light on, indicating a leak in the brake system. This switch needs to be reset to the center position to turn the light off. I don't have my shop manual handy atm, but the reset procedure should be in the manual.

 

blue - i totally forgot about NPD ill have to give them i try. I usually get stuff from mustangs unlimited but they didnt have anything this time.

star - So really its just a switch rather than a valve? Is this really how they were back when they were new? I have been living with it for a while but its getting to the point where it is VERY annoying to drive. I have followed the instructions on how to centralize it from the shop manual and havent had any luck, so i was thinking maybe the piston, or switch inside the body of the unit is stuck. So i dont know at this point.. it may be easier and better just to swap the fronts to disc.

 

Yes, most cars since 1967 use a similar setup. It's quite possible the little piston inside the distribution block is stuck. Loosen one of the bleeders in the back a bit and feed it into a small bottle of brake fluid with a small tube, then stomp on the brake pedal really hard. If the light doesn't go out (or flick off and then on), go to the front and repeat. This may unstick the piston.

I drove with 4 wheel drums for 7 years. It's kind of a pain, but it's manageable. You just have to be aware of the fact that you don't know which way the car is going to go if you stomp on the brakes, and that the brakes tend to want to lock up easily.

If you can afford the disc upgrade, I'd definitely recommend it. I recently put the CSRP KH-style discs on my 67 and I love them.

 

Oh ok, yea it's really just gotten to the point where i dont want to deal with the drums anymore. They aren't worth the constant adjusting and having to compensate everytime i hit the brakes. Right after my last post i looked around for disc kits and found one for 899 on mustangs unlimited. The non-power kit from SSBC if im not mistaken. Where did you get your kit? Thanks for the quick replies back i appreciate it.

 

I have had 4 67/68 Mustangs over the years, and they all had drum brakes. They all STUNK when it came to stopping! Everytime I had to make a quick stop, without locking up the brakes, it was a different story----swerve left, swerve right, and, if wet, don't stop at all!!! That's the deal with drum brakes! I installed front discs on my 67 F/B last year, and it's like a new car! Stops straight every time, wet or dry. That's the fix for what ails you!!
As for the switch, they are non- operational, due to age, on 99% of 67/68's. Furthermore, I don't believe you can buy a replacement part, and they're a b%#*h to try to repair, but take heart, if you install front disc brakes, one of the perks is you get to remove the switch and throw it away. You will, however be installing an adjustable proportioning valve for the disc/drum setup, so you'll have enough plumbing to do to keep you happy! LOL.
Seriously, replacing the front drums with a disc brake setup is one of , if not the most, important upgrade you can do on your 67. The difference is truly staggering. You won't believe what a pleasure it is to hit the brakes and know what lane you'll be ending up in when you finally stop!!!
Hope that helps,
Jay67fast

 

I agree with Jay. It does make a huge difference.

I got my CSRP (http://www.discbrakeswap.com/) kit through Daze of DazeCars (http://home.bresnan.net/%7Edazed/test) who pokes his head in here from time to time. Unlike many other kits, the KH-style CSRP kit is a bolt-on for 65-67's, not requiring a spindle change. It also fits under 14" wheels designed for disc brakes, which kept me from having to buy another set of wheels.

 

Ok great, thank you very much everyone i really appreciate it. I guess i will be looking into discs then haha. Seems like a MUCH safer route as well. Well i guess i know what i need to do now... save lots of money haha. Thanks again all.

 

a couple of cents more:
I started as a mechanic in the era that used drum brakes and if adjusted and operating properly, the pulling from side to side won't happen. However, from a effectiveness point of view, all of these "pony cars" came with marginal brakes. In those days people also drove different because they needed more stopping distances.
The brake switch manifold being discussed was a first attempt by DOT to make owners aware of diminished braking and was designed to inform people that there was a problem in the brake system pressure. (e.g.. 1/2 of the system was bad).

I'm with the others here, going to at least a front disk system will improve the overall saftey of operating your car and should give a small increase in value.