Brakes 89 GT sudden no brake pressure

[FetusLasVegas]

While driving last night I went to brake and got nearly no response from the pedal till it was almost bottomed out. Pumping the brakes builds enough pressure to stop. Checked the reservoir today and it’s empty. Right now with car running if I pump and hold the brakes the pedal sinks a bit after. There doesn’t seem to be a leak anywhere. How can I tell if it’s the booster or master so I can get this fixed?

 

[Mustang5L5]

Stock drum brakes? Pull the drums off and verify no leak from the wheel cylinder inside.

If you are absolutely sure no leaks, id change the master cylinder.

 

[FetusLasVegas]

Yes, stock drums. I’ll take a look now.

 

[Blown88GT]

...Checked the reservoir today and it’s empty....There doesn’t seem to be a leak anywhere. How can I tell if it’s the booster or master so I can get this fixed?

Empty reservoir & no leak indication is probably one of the rear wheel cylinders. Always replace both sides, they are only $13/ea at AutoZone.
https://www.autozone.com/brakes-and.../brakeware-wheel-cylinder-rear/19711_710655_0

 

[FetusLasVegas]

I checked passenger rear drum, looked clean.

Followed brake lines up to passenger front. A little towards the front from where the fuel and brake lines come together I noticed a small stain on the floor. And some splashing behind the passenger front wheel well that wasn’t uniform with the drivers side. Where the subframe meets the plastic of the inner wheel well there is a drip of yellow fluid. There is quite a bit of yellowish fluid on the subframe as well.

I’m guessing there is a leak, somewhere behind the wheel well plastic. Ran out of time tonight, but I will follow up when I can get back in there and see what’s going on.

 

[Mustang5L5]

That would be where the single brake line to the rear brakes comes down from the firewall area.

I'd say you found your leak

 

[FetusLasVegas]

That would be where the single brake line to the rear brakes comes down from the firewall area.

I'd say you found your leak

So, I obviously won’t know what the exact situation is till I can tear into it on Monday, but is this something I can plan on working on myself or should I just take it to a shop?

 

[Mstng93SSP]

You should be able to change that line yourself. I would use flare nut wrenches especially if the lines are old.

 

[FetusLasVegas]

I have a couple quick questions:

1. My plan is to cut the bad portion of the line out and replace it with new. Is this ok, or should I be replacing the entire length fitting to fitting that has the leak?
2. What size diameter are the lines (89 GT stock brake setup)?
3. What kind of flare, double or bubble?
4. Will the auto parts store have new fittings? I found the lines listed online, but can't seem to find if they have the fittings.
5. As far as I've found, this is what I'll need to complete this job. Am I missing anything, or using anything unnecessary?
-new brake line spool. My local store has coated steel.
-new fittings
-dot 3 fluid (not sure how much I'll need, but I'm assuming the system is nearly dry)
-line/flare nut wrenches
- flaring tool
-line bender
-line cutter/deburrer
-vacuum pump

Thanks again for all the help. I'm hoping to have this and my FPR replacement done tomorrow, which will keep me right on schedule for solving all the preexisting problems just in time to put the car away for the winter!!!

 

[General karthief]

Have you checked Inline Tubes or Classic Tubes

 

[FetusLasVegas]

Have you checked Inline Tubes or Classic Tubes

Just did. My plan is to get a spool of line and DIY. 25ft spool is under $30 plus fittings. Seems to be the most cost effective route. Do you have any insight on my questions? I would like to get going on this first thing in the morning.

 

[Boostedpimp]

I have a couple quick questions:

1. My plan is to cut the bad portion of the line out and replace it with new

This would work fine. You can rent the flaring and cutting tools from most auto part chain stores as well.

 

[nickyb]

I do like to save a buck whenever I can,that being said some head aches are just not worth the cheese. My best advice is get new prebent lines,then it is r and r and your good to go or stop

 

[General karthief]

I'm lucky that I get to hang around real mechanics in a fairly well equipped shop, most of the members here are experienced pro's, the tech/how to stuff here has made a hero out of me many times, that said, my observations around the shop and from hanging around here I would say your on the right track for dealing with your problem, I will advise taking a good look at all the brake lines making sure there are no other places that have the potential to leak. Hitting that brake peddle produces a LOT pressure, and it's hard to pull the seat upholstery out of your but when your suprised by not having any.

 

[FetusLasVegas]

I'm lucky that I get to hang around real mechanics in a fairly well equipped shop, most of the members here are experienced pro's, the tech/how to stuff here has made a hero out of me many times, that said, my observations around the shop and from hanging around here I would say your on the right track for dealing with your problem, I will advise taking a good look at all the brake lines making sure there are no other places that have the potential to leak. Hitting that brake peddle produces a LOT pressure, and it's hard to pull the seat upholstery out of your but when your suprised by not having any.

I’ve decided to diy replace my entire intermediate line. By getting a spool of line I’ll have plenty left over to do the fronts come spring time. The rears are brand new. Still needing confirmation on the type of flare. More confusion has been thrown in the mix. First I was reading either double or bubble flare and was leaning towards bubble, but now I saw in a vid a guy was using SS lines and said to use 37* single flare. I planned on using SS lines, which he says to avoid for first timers...

Off to pick up the tools I need that I don’t have. I guess I’ll have a better idea once I can remove the existing line. Will update. If anyone sees this and has further advice before that, please let me know!!

 

[FetusLasVegas]

I bought a spool of coated steel brake line and the appropriate fittings for what I was replacing. Cost me less than $30. Using the old line, which I had removed from the car as a guide, I bent the new brake line to match the design of the original. I was able to feed it through all the preexisting c clips. Connected everything up and tightened it down. Flushed and bled the entire system and everything is good as new. For the parts and two pints of dot 3 I payed less than half of what a prefabbed line goes for at its cheapest.

 

[General karthief]

And parts/stuff left over!
WIN!