Master cylinder or booster?
#1
Master cylinder or booster?
OK, I am still uncertain as to which one to replace. Does anyone know how to perform a test to isolate the two? Here is my problem;
No pedal, even after bleeding. The bleeding process seems good, until I start the truck and I loose all pressure instantly. The rears are adjusted good and I have plenty of pad in the front. I need to determin which one to replace. I can keep pumping the pedal until I get "some" pressure, but when I keep pressure on the pedal, it goes back down to the floor. I am working with a 1995 Bronco. Also, no visible leaks and the problem came on suddenly.
Any and all help is appreciated,
TK
No pedal, even after bleeding. The bleeding process seems good, until I start the truck and I loose all pressure instantly. The rears are adjusted good and I have plenty of pad in the front. I need to determin which one to replace. I can keep pumping the pedal until I get "some" pressure, but when I keep pressure on the pedal, it goes back down to the floor. I am working with a 1995 Bronco. Also, no visible leaks and the problem came on suddenly.
Any and all help is appreciated,
TK
#2
#3
OK, I changed out the master cylinder and still no pedal. Actually, it is a little better, so I guess it did not hurt to change the master cylinder. Now, I have great pedal pressure when I pump the brakes with the motor off and the pedal stays pressurized. But, as soon as I start the motor, the pedal goes down to the floor. One thing I did not do, and I am kicking myslef now, is measure the push rod distance. I guess I figured that I did not disturb that part, so it should not have needed adjusted. I can take the MC back off tomorrow and check the diatance without effecting the lines. This will prevent me from bleeding AGAIN!!!!
So, any other suggestions? I am open to all.
Thanks,
TK
So, any other suggestions? I am open to all.
Thanks,
TK
#4
#5
#6
Update:
Not being totally satisfied with the "self adjusters", I removed the drums to find them both bad and almost no linings on the shoes. Duh, I thought!!! Well, after replacing the drums, shoes, adjusting and re-bleeding...I still have no pedal!! Obviously, I have better brake action now. I am about out of ideas. I hope you guys have more coming. Also, I put the entire truck up in the air and locked in the front hubs. When I activated the brakes, all four wheels stopped really good.
TK
Not being totally satisfied with the "self adjusters", I removed the drums to find them both bad and almost no linings on the shoes. Duh, I thought!!! Well, after replacing the drums, shoes, adjusting and re-bleeding...I still have no pedal!! Obviously, I have better brake action now. I am about out of ideas. I hope you guys have more coming. Also, I put the entire truck up in the air and locked in the front hubs. When I activated the brakes, all four wheels stopped really good.
TK
#7
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#8
The only way I have to check vaccuum is to remove the hose with the engine running. I did that and it seemed to have pretty strong vaccuum. As I pump the brakes, the pedal gets high and hard. While keeping pressure on the pedal, I start the truck. As soon as the truck starts, the pedal creeps down towards the floor.
TK
TK
#9
That should happen, that indicates that the booster is functioning. As for the pedal being soft/not there, do you hit the floor before you start breaking or it just isnt as high as you want? After a break job the brakes wil lbe soft until the pads/shoes wear into the rotors/drums. The only thing that makes a soft/spongy pedal is air in the system. What year is the truck? ABS or no?
#12
Most people will say that you have to have it professionally powerbled to get the air out. I have found if you have everything adjusted and bled as good as you can get then take it out on a back road and brake HARD so the ABS kicks in. Do this a few times and then double check your lines with a quick bleed and you should be good to go. Has worked everytime for me, if you don't want the hassel take it somewhere and ask for a pressurized brake fluid flush, will do the same thing and completely replace old fluid.