So tonight I finally had to time to finish the down pipe and turbo rebuild I did. The sound better already. I was getting ready to back it out of the garage when I notice the brakes fade to the floor.

What it doing;
When the truck is running it seem like it has a bad master cylinder. Padel driff to the floor from under your foot. So I changed it out to a new one I had it the garage for a pryer trouble shooting problem. No better. If I pull the vaccum off the booster it will get hard and push the pedal up. It hard to push. Going to try to get a vaccum tester tomorrow to see what it pulling. What should it be? Is it the booster going bad? Brakes are bleed, rear adjusted right. Truck been sitting 3 weeks now.
It just seem to never end.



Sorry need to vent!

 

Doesn't sound like a bad VC to me. You already pulled the vac line off the MC and the brakes where hard. Vac should be 20 lbs at idle.

Did you bleed the MC before hooking it up? If you don't, it will just add a bunch of air into the system.

 

Bleed the new mc. Bad booster?

 

Changed the booster tonight and it made no difference. Bleed each line to find no air. So I had the auto store order me a new master cylinder. Well see if it helps?

 

When all else fails, I gravity bleed the brakes.

 

i got money on a bad abs valve.
that was the first mod i did on my trucks back in the day. drive it out of the dealership straight home and bypass the abs. all of a sudden they had properly working brakes.

 

Well new master cylinders in and still the same thing, hard pedal at first, seeps out from under you to the floor. So tomorrow will be a trip to the auto store to get the stuff I need to delete the abs block. Tom do u have any other info on how or what u did? Will it make or throw any codes with out it?

 

i just bypassed it. since all my trucks are computer-less, i don't have to worry about codes.
once the 02 gives me problems i will bypass that one too, and worry about the computer when the time comes.

i measured for the line, and unscrewed the fittings off the block, then put a section of line in where the block was. if i remember correctly, i used a 6 inch piece of line. then bleed the rear brakes.

 

Tom will it make brakes better?

 

By passed the abs vavle and now the lights on and still have a soft pedal. I really need my truck up and running. So over the last few days I have. Replaced the brake booster, master cylinder. Bleed the lines. Today I by passed the abs vavle and re bleed the back brakes. I can't figure it out. Maybe the vacuum pulling to much?

 

Is your vaccuum pump still working?

 

How are you bleeding them?
You may just have alot of air.

Open all 4 bleeders till you get a good flow from all 4. Then do LR,RR,LF,RF bleeding each one 3 times before moving to the next wheel then check pedal. Check fluid in between each time you move

 

That how I bleed them.

 

I had a ranger that I ended up having to take it fir a drive and get the fluid warm and bleed them again and it was fine after that

 

Did you bench bleed the new MC if not that is your problem the abs unit also has a bleeder and needs to be bled as well but seeing as you deleted it don't worry about it .

I would also have a good look at the brake line that goes to the back brakes follow it to the back you will see where the steel brake line meets the rubber by the back fuel tank they seem to rot there all the time .