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Discussion Starter #1 (Edited)
Has anyone else had problems bleeding Strange Drag Brakes?

I initially installed a set on my 91 Mustang (dual piston calipers front and rear) a little over 2 years ago and it took me forever to bleed them initially. At that time I also installed a new 1.25” manual master and yes, I bench bleed the master before I installed it and yes, I am using DOT 4.

Since then I have replaced pads several times and it seems that every time I did them it was hell to get a good pedal. Eventually I even bought a power bleeder to make it easier, especially since I got tired of my girlfriend whining “how much longer” while I pulled my hair out trying to get a good firm pedal.

Fast forward to this last week…. I installed a second set of calipers on the rear to hold the car while building boost. I hooked up the pressure bleeder and pumped 2 quarts of brake fluid through the system trying to get the pedal firm. Even though it would pump up okay, the initial pedal went almost to the floor and it took 2-3 pumps for it to be decent. After pumping them up, they seemed to hold the car pretty well while building boost, but I was not happy with the brakes at all.

After a little research, I changed the lines on the master so the larger reservoir in the rear is feeding the dual calipers based on the recommendation from Strange for the dual caliper application, I hooked the pressure bleeder back up again and pumped another 2 quarts of brake fluid through the system trying to get the pedal firm. Finally, long after all bubbles were gone, on the first push the pedal still feels a little soft and goes down further than I would like but better than before. The second push it is firm and a little higher - pretty much like I would expect to be. Any additional pumping of the pedal doesn’t seem to change the pedal feel too much. This is probably “acceptable” though I don’t think it’s perfect.

Does anyone have any suggestions on improving the pedal firmness or is the initial soft pedal just a characteristic of have the 6 calipers (2 front and 4 rear)?

IMPORTANT NOTE: The Strange calipers have bleeders on the top and bottom. Typically you need to open only the top to get the air out. One of the things I discovered during this ordeal is that you should always open the bottom bleeders at some point during the bleeding operation. I didn’t get any air out but what came out was some of the worst looking brake fluid you can imagine. After only 2-3 years, the brake fluid system had collected plenty of crap and evidently every time I bled the brakes during prior servicing it had pushed some of it out the top bleeders, but a lot of it “settled” into the lower part of the calipers where it accumulated. From now on, I will always bleed the bottoms when I replace the pads!!!!

 

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Residual valves in the system? I always had to give a couple of pulls on the brake handle before it really firmed up nice. Residual valves usually cure that. Plus your flex lines from the frame to the calipers, if they are rubber or rubber based, that will give you a spongy pedal. If you don't have them get steel braded lines.
 

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Discussion Starter #3
No residual valves in the system and it has teflon lined SS brakes all the flexible connections.

When you say "pull the handle" does that mean you have a hand operated braking system?
 

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One thing to try is to jack up one end at a time and bleed that end in the air....it works!
Your master may have a too large a bore.It will not impede bleeding but may hurt brake performance.
 

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Put a residual in it. Take cap off master full it up leave it off. Open every bleeder start bottom inside wrk ur way to top outside. Do all them like that and c what happen. U don't need her do it all urself that way. Lol
 

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Discussion Starter #6
Put a residual in it. Take cap off master full it up leave it off. Open every bleeder start bottom inside wrk ur way to top outside. Do all them like that and c what happen. U don't need her do it all urself that way. Lol
LOL - I appreciate the suggestion. If you reread my original post, I mentioned that I bought a pressure bleeder so I really don't need my girlfriends "help" anymore.

One thing I noticed today. I drove the car around some and used the brakes several times hard enough to break in the new rear pads. Afterwards I notice that the pedal was up and felt much firmer. I'm guessing that the pads wore in a enough to align the pad faces with the rotor well enough to reduce the amount of movement the calipers needed to push the pads against the rotor. Bottom line is they seem good now.
 

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Bad master?
 

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Discussion Starter #8 (Edited)
Bad master?
Naw suh, Master treats me reel goodun deez days, no whuppins or nuttin no more.

(Sorry, I couldn't resist;))
 

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Discussion Starter #10
As I stated in the original post, I am using a pressure bleeder. It fits over one of the caps of the master cylinder and the other cap is left on to allow pressurization.
 

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I always gravity bleed since I'm working alone and don't have any of the fancy bleed systems. We had a vacuum system at one shop, didn't like it much.

The 4 piston calipers seem to have some cavities inside that like to collect air bubbles.

Once I get fluid moving in the system, I'll tap the calipers lightly with a rubber/plastic tip hammer to help dislodge any trapped air. I'll go around the car at least 4 times before I'm confident all the air pockets are gone.

In between rounds of gravity bleeding I'll give the pedal 3 or 4 slow, steady pumps. Nothing fast.

So far this has worked on every car I've bled brakes on.
 

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Had a friend of mine have a similiar problem installing an aftermarket master cyl on a mustang, cant remember the brand, but he had a big problem getting all the air out and getting "good pedal". Worked on it for several weekends. Turned out all he had to do was give it just a little more push rod travel (wasn't really traveling all the way) to help push the fluid/air out.
 

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As I stated in the original post, I am using a pressure bleeder. It fits over one of the caps of the master cylinder and the other cap is left on to allow pressurization.
My buddy used the same thing, twice, ended up being the push rod adjustment, something to check. Cant hurt.
 

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With the pedal adjustment, make sure there is a little free play in the pedal. I've seen one instance where the pedal was keeping the piston from fully retracting in the MC.
 

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Discussion Starter #16
Started at the furthest point - Yep.
Pedal adjusted with a little play - Yep.
Tapped on calipers with plastic soft blow mallet to "loosen" bubbles - yep.

I went through everything that is common each time. As stated in an my earlier post, driving it and seating the pads seemed to help take a lot of the softness and travel out of the brake pedal "feel". The brakes are acceptable now.

I appreciate all of the suggestions.
 

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Started at the furthest point - Yep.
Pedal adjusted with a little play - Yep.
Tapped on calipers with plastic soft blow mallet to "loosen" bubbles - yep.

I went through everything that is common each time. As stated in an my earlier post, driving it and seating the pads seemed to help take a lot of the softness and travel out of the brake pedal "feel". The brakes are acceptable now.

I appreciate all of the suggestions.

Cool deal. Weve come a long way from opening up the valve and letting the fluid squirt into a rag, lol. At least thats how we did it 20 years ago when i first learned to do braks. Those little vacuum pumps at the valve work great.
 
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