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1966 Mustang Power Breaks

2K views 14 replies 12 participants last post by  BlakeTX 
#1 · (Edited)
1966 Mustang Power Brakes

I purchased a 1966 Mustang 289 with drum brakes on the rear and disks on the front. I'm not sure if the previous owner installed the disk brakes or if they were a factory option. Was it even possible to an original 289 v8 car with power front disk brakes? I'm assuming not. The set up wouldn't bother me so much if the brakes worked well and if the engine bay wasn't so messy. I have attached pictures of the master cylinder and the power brake booster as well as the control valve. I'm not sure what the control valve is therefore at least I'm assuming its a control valve. I know that a OEM master cylinder shouldn't have a plastic reservoir. The brakes don't engage or do anything for half of the pedals stroke, I tried bleeding the brakes however air bubbles for the front brakes never stopped. I tried bleeding them until I ran out of an entire bottle of brake fluid. At this point something must be wrong. Should I switch back to an OEM style non power brake system? or should I just change the master cylinder to the correct one? im not sure if the power brake booster will work with the original master cylinder.
 

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#2 · (Edited)
Not sure exactly what you have going on there. I don't recognize that tiny booster or master cyl. That is a proportioning valve by the export brace, (edit: factory brace. So, where the export brace should be, lol) which you would need, but that has got to be the sloppiest install I've ever seen. I have power disc on my car, but it's all using Mustang Steve stuff with a Foxbody booster and Maverick master.

Also, it's "brakes", not "breaks". So's you know.
 
#3 ·
I don't recognize that kit. While I could wrong, I think you are looking at the dreaded too short pedal actuator rod/mismatched brake cylinder problem. If the rod from the pedal to the master is too short, the pedal hits the floor before the cylinder travels far enough to do much good. If the rod is too long, then the brake pedal is held too high in comparison to the gas pedal.


It seems to be a common problem with aftermarket kits. I made up an adjustable rod, but now while my brakes work reasonably well, the pedal is pretty high off the floor. Do a search. My limited hunting unearthed plenty of people with the problem, but few with a truly good fix.


good luck
 
#4 ·
Man, for the sake of everyone's safety in and around that car, start over with a correct manual disc brake (single bowl) metal master cylinder at the very least, or BETTER YET a dual bowl metal master cylinder, and if you must have power brakes consult with SSBC, CSRP, the aforementioned Mustang Steve or someone at NPD to point you in the right direction.
 
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#6 ·
Thanks for the responses. I will probably switch to a manual brake system and dual bowl master cylinder. My 6 cylinder has drums all around and a single bowl master cylinder it works so much better than this car. Do I still need the proportioning valve and is this just because the front is disk and the back is drums and is there an OEM replacement? and what is the bronze coupler next to the master cylinder called? my 6 cylinder also has one. I apologize in advance for all of the questions I can figure out how to install a master cylinder but as far as deciphering the other objects around it I have no clue.


On the topic of pedals my brake pedal is much higher than my gas pedal. Maybe the brake pedal is too high but my gas pedal is too low any ideas of what could cause that? could the pedal linkage for my gas pedal be bent? I've looked at replacement pedals I believe I have everything but could I be missing a spring of some sort. My 1965 6 cylinder mustang has a higher gas pedal for sure.
 
#7 ·
If you keep the front disc brakes, you will need to keep the proportioning valve. I believe the earlier post was correct in that you may have too short an actuating rod in the master. I am fairly sure that front disc brakes were an option, but not power assisted. You might want to try just a dual bowl master and see how you like it.
 
#13 ·
Ok I have heard the distribution block being called a proportioning valve before and I have watched online tutorials before where people didn't install a proportioning valve I am assuming this is because they had all 4 drum or all 4 disk I'm not sure. Regardless I understand that the master cylinder may not have been bench blead properly I will try that first as well as cleaning up the location of the proportioning valve and the lines running to it. This however will be temporary.

I am going to try to find a dual bowl mater cylinder that will work either by itself (manual brakes) or with the power break booster that is already present. The issues that I'm sure I will encounter: the push rod that enters the master cylinder is probably not original and therefore my pedal wont be in the right place, and then there is the issue with finding brake lines that will accommodate the new mater cylinder.

I'm really just not a big fan of the plastic revivor and the amount of finagling that took place in getting this one to work. Why not buy an OEM part or a dual bowl upgrade why spend so much money on junk.
 
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