Today out sanding roads , a few hous into it , brake peddle goes to the floor , very little breaking . Check for fluid and it ok , visual check the wheels and see no leaks . Step on the peddle easy , right doown to the floor . Try pumping and peddle comes right up but still almost no breaks . Nurse it back to garage and found a small leak in the line near the MC . Patch that , fill the fluid and have slightly more break but not much. Same symtoms as before with the peddle . What's up , Thanks

 

Umm....The Only Thing I Can Of Is That You May Have Got Dirt In Your Break Fluid Tank/Compartment...
Hope That Helps

Mike

 

You will have to bleed them after that leak repair, the lines are full of air, When you pushed the pedal down the fluid goes out of the system through the hole in the line, and when you let off the pedal air is sucked in........

 

If after bleeding there's still a problem you may be experiencing blow-by inside the master cylinder. When brake pedal travel exceeds the norm, the piston gets forced into an area of bore that has less wear therefore more friction (may even have surface rust) scoring the piston. Requires rebuilding/replacing the master cylinder.

 

Figured there would be air in the line , this was a bandaid so I could get back on the road . What puzzles me is so little stopping and also the peddle. When I step on the peddle normal it goes right down and have a little brake when it gets near the bottom . When I pump it the peddle comes up but no power assist. When the peddle goes down the brake and ABS lights come on , if I tap on the brake the lights go out

 

No power assist? Yours has vacuum boost and not power steering boost, right? Do you know which end of the truck brakes had the leaky line, front or back? It sounds like air has gotten into one side of the ABS electronic variable brake proportioning valve to me. This would cause the ABS lite to come on, and brake fluid to be routed to just one end of the truck. If you don’t have access to a power bleeder at your shop, I think I would take it to a muffler shop and ask for a complete brake system fluid flush/bleed before I do anything else then begin troubleshooting.

 

First of all did the pedal go to the floor BEFORE or AFTER the leak? If it was before, then your master cylinder is due for replacement. If it was after, then you already did what was needed. It sounds like there is still some air in the system. Does the pedal go down easy or is it difficult to push? That would tell you weather or not the boost is working. Let us know what you figure out.
Tom

 

I suspect that the leak was there first , just ddn't see it . Squirted on the inner fender so it didn't show on the ground . It is vacuum assist so maybe when I pump it up it runs out of vacuum at idol . Have some time this afternoon and will try bleeding . The peddle goes down easy until I pump it up , then it's like the engine is not running , (two feet and all you got ) . I'll let you all know , thanks for the suggestions.

 

I think it's the front brakes , it's the rear section of the MC

 

ticki2

This is a little off what you wanted to know, but I'm going to tell you anyway because I think its the only way to do it RIGHT!!!!!!!!!!! I have done this to all my cars and trucks. When you have a brake problem and you have to bleed your brakes the most importain thing to do is buy DOT-5 or synthetic brake fluid. This fluid will work in all brake systems new or old. The old brake fluid (non synthetic) will hold moisture in your system and will cause the brake lines to rust from the inside out. Since you have to bleed your brakes anyway bleed all the old fluid out and replace it with synthetic.

I have done this to at least 3 dozen cars for all my friends. I found this to be the answer, when one of my GTO's lost it brakes completely, it was because pre 1967's have a single bowl master cylinder which means when anything leaks you loose all brakes

Give this a try and I know you will be happy.

CRIS

 

Found another leak down stream of the other so replaced the whole line from the combination valve to the split block for the front breaks . Then started bleeding the front system . First the MC , then at the combination valve then at the wheels. Bleeders at the wheels are frozen so I cracked the banjo at the calipers , not the best I know . The peddle still goes to the floor if you keep pressure on it . The booster seems to be working if you keep the RPMs up . It's looking more like the MC is gone . You can pump the break to get some peddle , but if you keep pressure on it will go down .

 

It,s possible the MC is part of the problem, but if you had good brakes before the leak you probably need to bleed them correctly. You will have to start at the farthest cylinder from the MC and work toward it. The front and rear hydraulic chambers in the MC may appear to be 2 separate systems, but when air is sucked into the lines it will be circulated around within. You won't get all the air out unless you can bleed them through the bleeders as it will leave a lot of air trapped in each piston area. After all of that, the pedal still goes to the floor you have a MC problem as stated in an earlier post. Sounds like you need to inspect all of the lines for rust and replace as needed before doing a lot of work over and over........

 

Pros and cons on using heat to get the old bleeders out . ten years of salt has taken it's toll .

 

One feller on here had good luck taking a 6 point box end on it and striking the bleader with a small hammer, kinda like an old school impact wrench. He didn't need any heat.

 

Exactly. I had the very same issues with my brakes. I went through three master cylinders to get it right. By that I mean ALL the air out. Until I got all the air out, I would hold pressure on the pedal and it would go to the floor just like there was a leak. Now I have a great pedal and great brakes (since I up graded the rear cylinders).
Tom