Weak brake response

OK here's my problem, this past summer I changed up my Manual brake system when i put in a hydraulic clutch in for my t5, when i did this i put in all new lines from the proportion valve on out(i still have the original proportion valve from the drum brakes set up that came with 69 cars). Previously a year before last i put explorer disc brakes on the rear, but this did not change the stopping power. But since i put new brake lines in i have only a quarter of the stopping power that i use to have. Saying this i made sure that all of the air was out of the lines when i bled the system.

Any ideas what i should check/change????

 

it sounds like you are not getting full pressure to some if not all of the brakes. a bad brake hose can have a flap inside that will block flow to the brakes. this may show up when bleeding. that brake wont get a good flow to it.
you may have some seized calipers.
you may have oil contaminated brake pads.

did the brakes feel fine after the rear disc conversion but then go away after the new lines? or did they feel bad after the rear disc conversion?

 

They worked great after the disc brakes swap, just recently after all of the lines were changed the trouble started, I'm pretty sure i got all of the air out of the lines so that's whats puzzling me

 

Do you have disc brakes on the front??
Did you install the rear calipers on the correct sides??? (The bleeder valves have to be at the top of the calipers) If not...You wont get the air out of the system.

 

yes, to both questions, I have disc brakes all the way around, and i haven't done anything to the disc brakes/calipers since installation so there shouldn't be any problem there since it worked great until i changed the lines up front. Is it possible that there's air stuck in the proportion valve itself?

 

could you have crimped one the metal lines or have some debris caught in one of the lines.

 

Is the pedal harder than it used to be?? Less or more travel??

 

Possible you have air in the system. Did you change out the lines at the prop valve one at a time? If not you may have mixed up where they belong.Debris in the prop valve will give you fits as well. As Bryant stated...Kinked/pinched line debris in a line etc...I tend to think your master cyl is on its way out....

 

I wonder if the usual happened and the master took the seals out when bleeding. I think thats what Petes getting at.

 

I put a new master cylinder on it when i did the disc swap so the seals are new on it, i guess it could still happen.

 

You installed this master cyl before doing the rear disc swap and had no issues with it correct???

 

yes, correct

 

I have to agree with the line problem. Sounds like a line is swelling under pressure or you have a defective line. If the inner sheathing of the rubber line tears or has a small rupture, it can cause all sorts of headaches and can be hard to diagnose.

 

ok, ill have to check on the rubber lines then to see if there any ruptures.

 

Are you using a power brake booster? If so, the booster may have failed. Check your vacuum supply first before condemning the booster.