Strange Engineering Master Cylinder

[kdanner]

That does sound like it may be an oversize master. Look on a site like rockauto.com where they have pictures of the part and give the bore size. As I recall a 93 Lebaron is a 7/8" of the sterotypical Mopar style dual cap master and a 95 Dakota is 15/16".

[Richard Grant]

Have somone pump the petal while you bleed the lines. It sounds like you may have an obstruction in a line. You should get a high pressure squirt at each wheel if everything is correct. A stock master should work fine with drum brakes. Have you replaced all the stock lines? For drum brakes 7/8's master should be the ticket. If you changed from power to manuel brakes then your problem is the petal ratio. Power brakes have a much lower petal ratio and you must redrill the petal and increase the ration for manuel brakes. It may also require relocating the master for a straight shot from the petal thru the rod to the master.

[Tom Goldman]

Richard's probably got the right answer.
Most power brake pedals have a hole that gives about a 4 to1 ratio.
If thats the case, just calculate the distance to get about 6 to1 and drill a new hole in the pedal.
Definatly 7/8" -15/16" for drum / drum system

[brent flynn]

Richard, my car is factory manual brakes... all system is new...i didnt bother to check the piston size, when i installed the Master Cyl, about 1 1/2 yrs ago... ive since changed line locks, thinking that was the problem, but i believe its just the wrong master cyl. Or, its just a piece of junk. We used the Chrysler part, on my brother's 10.00 car, and it worked perfect. I just couldnt remember what car it came off of... All you have to do , is , notch the holes out , a bit, make a new pushrod, and you are in business....Ive bled brakes several times... doesnt help... BTW, the car drives like a Caddy, with the Global west stuff, adjustable Baer tie rods, and moroso springs... lifts straight, now. It used to twist on launch. 1.485 60fts , with bracket engine and 4.11 gears, bias slicks, 2400 footbrake...

[Richard Grant]

I would install a brake pressure guage on the front brakes. If you do you will love it when doing a burnout. You can pump the brakes to a set level each time. I usually set mine at 900 for my burnout.
You are running factory steel lines? AN lines do not work well for brakes. You can the brakes pressure guage to determine if the backs are ok also. You should get about 5 to 6 hundred pounds on the first stab if everything is correct.
No one that I know of has had a problem with the factory master when staying with drum brakes. Make sure that your master is not bigger than 7/8's. If it is that could be your problem. You may have chosen a master that was designed for disk brakes if you don't know the size or application.

[brent flynn]

Originally Posted by Richard Grant

I would install a brake pressure guage on the front brakes. If you do you will love it when doing a burnout. You can pump the brakes to a set level each time. I usually set mine at 900 for my burnout.
You are running factory steel lines? AN lines do not work well for brakes. You can the brakes pressure guage to determine if the backs are ok also. You should get about 5 to 6 hundred pounds on the first stab if everything is correct.
No one that I know of has had a problem with the factory master when staying with drum brakes. Make sure that your master is not bigger than 7/8's. If it is that could be your problem. You may have chosen a master that was designed for disk brakes if you don't know the size or application.

Yeah, I have all steel lines, and new rubber lines... I will pull master cyl, and measure it... Maybe, i should go to Napa, for a brand new one? (If this one checks out too big, or otherwise.) Im gonna put a brake pressure guage on the car...a good friend of mine, is giving me one. My Dad, had a '68 Bird(back halved) with 14.5/32's and never had a prob doin burnouts, and it had factory master cyl, was also manual brake car...

[brent flynn]

Where is the best place to source one? Napa is not showing a 7/8'', on line... i will call them tomorrow... Carquest, also...