B pedal slowly going to floor w/eng running

xt01815

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Vacuum lines are not your issue, they assist the brake booster but do not cause the pedal to go to the floor.

Do not put Teflon tape on your brake line flare joints. If they leak replace that line. The flare joint should seal against the male connection on the other side. The nut pushes the two together to seal them together.
As for Teflon tape. I hear you I really do and I completely agree with you. However the way I do it and was taught, anything that may need tape should only have what it needs to seal and to never ever cover the last thread. So that there would never be a chance of cross contamination. I typically use less than normal on a fluid connection such as brakes so as to help reduce air being sucked through the thread and back into the system or u-turn through the bleeder giving a false inspection while opening said bleeder for the job at hand. I hope I worded that right lol. By the way I want to thank you guys a head of time for the quick response. And the helpful input.
 

xt01815

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That sounds like your master cylinder is defective. Your brakes would maybe go 1/3 Tom 2/3rds down to the floor and feel spongy but not go to the floor if you had a little air in your lines.(Guessing you did not have any.).

I would do this test. Bleed again, then just hold the pedal down, see if it sinks. When you pump it may be sucking air into a line. But if you just push and hold and it goes to the floor it’s your master cylinder. Maybe release slowly once or twice, then see if it goes to the floor. Either way at that point I would warranty the master cylinder.

One last thought. There is a rod that goes from the booster to the master cylinder. Maybe confirm the old and new are the same length and have the same travel.
I will do that tomorrow. And exchange if no change in symptoms.
 

quickster

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I deleted the rabs valve on my 87. It was always damp looking where the wires would go into it. Once i deleted it I finally had good braking. Not that these things brake good to begin with, but it stops better.
 

xt01815

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So yesterday. I got a ride to the parts store and exchanged the b master. Got a kit to bench bleed it. (I bleed the 1st new one the old fashioned way). Today I bleed the 2nd new one and gravity bleed all 5 fittings. Got a helper to pump for the fronts to double check them and tapped on the calipers to help. Started the truck and much much better. It's just like big Bart said as of now. 1/3 the way to the floor and holds well. I test drove it to set the brakes and now it's less effort to slow down. Thanks to all you know who you are. I now can finally finish my trip to the dump that I started 4 months ago lol.

This all started on my trip to the parts store and then the dump. My goal was to get front wheel bearings. And other normal maintenance parts. They only had half the bearings and said the others are at another store near by if I wanted to go get them. So I was like sure cause it's on the way to the dump. I got the other bearings went to leave the store. Pulled out and when I got to 4th gear the clutch was slipping like crazy. Limped it home. And after a while I got the trans out and found that the springs and spring retainers in the dmf was flopping around all over the place. Couldn't find another one so I got the luk smf conversion, rear main seal, clutch master, and slave. Also got the fuel return line kit. I got all that installed and BAM!!! Brake problems. I'm sure I still have some air intrusion somewhere. But at least now I can get an inspection.

So again thanks for the help. Getting frustrated means for me to step back and let someone else give a more relaxed input. I'm just anxious to start driving it again. Cause I feel like a sardine trying to get back in the can when borrowing my dad's ranger lol
 

Big Bart

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Keep in mind many of us entered the IDI pain funnel like you. These trucks are ~30 years old, most have +150,000 miles, and many were not well maintained by the prior owners. So it’s one thing after another the first few months. But they are Ford tough and with some love and tlc they are good runners. They are generally easy to work on.

BTW my 2007 F150 gasser I bought when my other truck was stolen was another pain funnel! (Tranny, brakes, PS pump, alternator, coil packs, fan resistor, etc.) But now the last 9 months it’s been trouble free.

That is why I take my time and shop for a deal on used cars, otherwise right now I would be $3,000-4,000 upside down in my truck vs $500.(Maybe not even that with these stupid COVID used car prices.)

It is sad and I mention this all the time. You just can’t assume a new part or rebuilt part is going to work out of the box. You actually need to assume it is not going to work. Then if after you complete the job the problem is not fixed, you know likely the part you replaced is bad.

Bottom line glad we all could help you get over the hump and running again.
 
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XOLATEM

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Hey guys, Just expressing a little appreciation and recognition...

I realize that this thread is almost a year old...but I just read it...still being relatively new to this site.

It only took a few emails and three days for xt to get up and running again...that is fantastic and you guys are good souls in the way you guided him through the diagnostic process and repairs...long distance and without the benefit of any pictures...

It helps that xt was pretty good at describing his parameters and what had been done...where he was thinking of going next...and the overall diagnostic exercise...

It all added up to a success story...which was heartening to read and follow.

So...I feel compelled to say...

The collective brain trust of this group is...in my opinion...exemplary.

If ever anyone is questioning the good-heartedness of just regular Americans and Ford truck lovers in particular...they need only peruse these pages and see example on top of example of sharing a wealth of knowledge, support, understanding and patience for their fellow enthusiasts and other all and sundry...

I am impressed and it also encourages me to be a better fellow human being.

I thought that I was pretty sharp but I now realize that the largest room in the world is room for improvement.

Thank you Gentlemen...
 
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