1969 mach1 brakes to right side
#1
I'm trying to troubleshoot a braking issue where the car brakes to right side. Its noticeable at high speeds when it pulls the wheel slight to the right on braking. It is not that noticeable at lower speeds. I also am troubleshooting why the distribution block piston pushes back towards rear, causing brake warning light to come on. This is what I have done so far (car is front disk / rear drums all original):

Prior to working on braking system:
* brake warning light constantly on
* car did not brake that well.
* rear drum brake were barely worn. Front brakes were worn about half way through.

Work done so far in order:
1) bled brakes and warning light went off until I rode it a few blocks before coming on. Repeated this twice and same result
2) changed all 4 brakes
3) noticed I had to pump twice while braking. I thought it was the way i bled them so did it another two times.
4) Replaced master cylinder, changed brake fluid and pedal sinking issue fixed.
5) I bought the proporting valve/distribution block rebuild kit from cougarparts and rebuilt them. Prior to rebuild, distribution block piston was stuck hard to one side. It was somewhat cruddy in both parts but not terrible. I cleaned them inside and out and replaced 0-rings and spring. Pistons now moved nicely.
6) I put everything back together and tested the light before bleeding. Light was off. While bleeding the rear passanger (1st step), the light came on and remained on throughout the bleeding.
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#2
OK i just fixed the brake issue of pulling to the right. I replaced both front driver and passenger brake hoses. She brakes straight as an arrow now. I'll chalk this one up for a win although I couldn't get that brake warning light to go off. At least now I have a new MC, brake hoses, rebuilt proporting valve and distribution block.
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#3
One thought comes to mind about the light. Sometimes after everything is bled, you have to mash the brake pedal firmly with both feet. This is supposed to center the valve and turn off the light, but only when you have equal pressure / no air in the system. If this does not turn off the light, you either have some more air trapped, or the valve is stuck again. Hope it helps JTS 71 Mach1

Ps, Don't forget about the rear hose from the body to the rear axle, as it can collapse just like the front hose did.
"We built these cars to drive the "HELL" out of them, not to be museum pieces!"  Carroll Shelby

2008 Mustang V6 5 speed "Diablo Sport Predator" tuner, 87 octane tune. WOW!
1994 Ford F150 Shortbed
1986 Honda 450 Rebel
1995 Honda Pacific Coast
1989 Jacobra / Jag xjs
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#4
I'll try that tomorrow. I probably could of used this tool. This keeps the piston centered while bleeding

https://www.musclecarresearch.com/brake-valve-tool
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#5
I use a vacuum bleeder instead of pumping the pedal to bleed the brakes. I haven't had any problems with the light coming on using a vacuum bleeder.

Regards,
Mike
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#6
A+ on the vacumn bleeder best way I've ever found to bleed brakes. I always heard a pressure bleeder was good too but I never got to use one. JTS 71 Mach1
"We built these cars to drive the "HELL" out of them, not to be museum pieces!"  Carroll Shelby

2008 Mustang V6 5 speed "Diablo Sport Predator" tuner, 87 octane tune. WOW!
1994 Ford F150 Shortbed
1986 Honda 450 Rebel
1995 Honda Pacific Coast
1989 Jacobra / Jag xjs
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