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Hi all - 1974 F250, RwD . I just completed rear shoes and drums and bled both rear sides without issue. Upon moving to the front right ( disc ) , I am getting a ton of air during the bleed process . It should be noted that the master cylinder bubbles and occasionally spits during this process. I’ve tried multiple times to get a steady stream of fluid, but I just cannot figure it out. The red brake light is on ( and has been for a few weeks now, even prior to the brake replacement ) . I have not done a bench bleed considering the rear bled just fine. Any help would be appreciated.
Did you address the metering rod on the proportioning valve? Some get pushed in, some need to be restrained in the out position. Mine has the one that needs to be held outward prior to / during bleeding.
I have this explanation and fig 12 for mine.
I don't have figures 7 & 8, but maybe this gives you a path to explore?
I pulled it out with vice grips and tried to bleed with the same results. It is directly below the Master Cylinder on my truck and not on / near the frame under drive seat like someone previously mentioned.
I pulled it out with vice grips and tried to bleed with the same results. It is directly below the Master Cylinder on my truck and not on / near the frame under drive seat like someone previously mentioned.
Some get pushed in. Mine is always out, but if I were to try bleeding with out some how securing it, it will pop in. The difference in brake pressure will trip it. Throw a red light too.
I don't know which disc you have, nor if sliding calipers or fixed calipers? What is the GVWR on the door tag?
If your seeing bubbles in the master cylinder then you need to go back and bench bleed till they are gone. If they don't go away then the master cylinder is junk. You will never get the safety valve reset until the mater cylinder is air free.
Thank you Mark A. This is what I was looking for. I didnt know if air bubbling / spitting coming from the MC during the bleed process was normal, and clearly its not and indicates a bench bleed is needed.
New master cylinder is not very expensive. If you need to start over with a bench test I'd use a new one. Actually I do use a new one. And on your truck there is an adjustment rod right behind it. I'd try to make sure that it starts at the correct length.
Attempted bench bleed and had moderate success. When I go super slow pushed all the way in, no bubbles. If I go quick and only a 1/2-1 inch in and out, I get bubbles in the small port. I have been doing this for the past 30 minutes with no change. Thoughts ?
Attempted bench bleed and had moderate success. When I go super slow pushed all the way in, no bubbles. If I go quick and only a 1/2-1 inch in and out, I get bubbles in the small port. I have been doing this for the past 30 minutes with no change. Thoughts ?
Thanks...
First of all, slow steady pumps are best for any brake bleeding pumps. Long and slow steady strokes are always way better than short quick jabs .Short quick pumps or jabs will cause foaming. Why you don't shake brake fluid in a bottle just before use.
