No Pressure

[Simple_Sam]

Ok, I've been bashing my head for 2 days on this, and killing my helping hands trying to get some feel into my brakes. So here's some history to see if I'm missing something.

I bought a 88' Ranger about 3 or 4 months ago, and I found it in non running order, and the brake lines were disconnected. Why? Idk. I got the trucking running good, put dropped Ibeams by djm and bought all new parts mostly.

I've replaced the front hoses, calipers and pads. The rotors seem pretty decent still. No stress cracks or heat. I've also replaced the center rear brake hose.

MC - Now when I picked this thing up, it had no brake booster. The MC was the newer still with the plastic reservoir. But all in all it was hooked up as if it were manual brakes. I've replaced it with the 85' all cast older MC. Switched the line ends to match up to the correct ports.

IE: Main port (closest to the firewall) Front
Secondary port (furthest from firewall) Rear

After bleeding the brakes I have plenty of pressure to the rears. But little to no pressure to the front. I've bleed these brakes till my face has turned blue with anger. Theres no air in the lines either. I've gone as far as disconnect all the front hard lines and distributor box and blow them with brake cleaner then blow all the brake cleaner out with air. Clean as it can be then re bled. Still nothing on the front.

I have no pressure in the pedal and its maxing out. The only time pressure is relieved from the pedal while bleeding is when the rear are bled.


Any and all ideas are welcomed. also I've checked for a proportion valve (seems to be a unicorn) and or rabs and there's no evidence of one ever being there. front and rear are separated from one another too. Theres only a brass T block on the front and a t block on there rear thats connected with the center hose.

I've googled for hours too, you guys are my last hope.

 

[kimcrwbr1]

Have you bled the MC it may have a bubble in it. If there is a bubble trapped in the piston it will still move fluid but the air compresses giving little pressure in a closed system. Have you tried cracking the lines at the master cylinder as you pressdown on the pedal. Put a large rag under the master cyl have someone pump the pedal three times and hold crack both lines at the same time and quickly shut them before the pedal hits the floor. Sounds like air in the master to me.

 

[kimcrwbr1]

http://www.youtube.com/watch?v=vOuDEiwiozQ This may help

 

[kimcrwbr1]

http://www.youtube.com/watch?v=l-Bd1P5Nbqk I was looking at this video and just had an idea for flushing and bleeding the brakes at the same time using vacuum pressure from the engine. take a long piece of clear tubing and a jar with two nipples in the lid similar to his hand pump. Hook one line to manifold vacuum and the other on a bleeder valve and use the vacuum pressure to suck the old oil out as you pour new into the reservor humm scratching chin the jar will catch the old oil without sucking it into the engine. The tubing would have to be stiff enough not to collapse under 20 inches hg and chemical resistant to brake fluid. My theory is you would not have to touch the brake pedal. Is it too late to patent the idea?

 

[Earl43P]

http://autorepair.about.com/od/fixityourself/ss/MC_bench-bleed_5.htm

http://www.superchevy.com/technical/chassis/brakes/0509sc_bench/index.html

http://www.denlorstools.com/home/dt1/page_7445/automotive_brake_bleeding_exclusive_tech_article.html

 

[Mark_88]

Aside from a problem with the master...which you may need to bench bleed (I bled mine on the truck and it worked OK but needs someone inside to hold the pedal while you connect the line)...also could be a possible leak or a problem in the T connector for the fronts...if bleeding the master again doesn't resolve it take that apart and check for proper connection and possible leak...maybe even replace the lines if they are old...

Only other possible leak location is the joint to the flex lines...check those if you haven't already done so...

 

[Simple_Sam]

You maybe correct with the air in the MC, now that I think about it, I've never really correctly bled the MC, just sort of put fluid in, pushed the rod a couple of times and called it done.... oops... I'll have to check it out this weekend. Plus since the truck is lowered and i'm too fat to just slide under the truck I was bleeding the truck with the rear on ramps and the front on ground. So I'm guessing that will just keep any air trapped in the MC instead of pushing it through the lines? Appreciate the help and tips. /dumbass.

 

[triumphrider-1]

The bleeding screws are on the top side of the caliper correct?

 

[Simple_Sam]

I did check that, while researching I came across a post in this forum about the calipers being upside down. So I walked out side and double checked that. The bleeders are above the lines. I have to relocate the bench bleeder adapters and do the bleed this weekend when I get alittle bit of time. I'll update accordingly, which I may still try to locate a proportion valve.

http://www.summitracing.com/parts/CLP-PV-2/

Found that little sweety, If the port threads dont match up to the current t-block junction, I am atleast half witted enough to locate the right flare nuts and flare the lines.

 

[Simple_Sam]

Good news everybody, I've figured out the problem! It was a defective master cylinder from the begging, there was a small pit in the cylinders bore that was catching the seals and tearing them on the primary side.

After taking it back and getting it replaced, it works great. So for now on I'm either going to just rebuild them or check all MC's before installing.

 

[Insanejughead]

As soon as I read the first post, I thought it was something to do with the MC. I was going to ask if you had disassembled it to see if it had the right rod in the bore.


Glad you found out it was a such a simple problem; it's just sad that it usually happens that way with all of us.

Got any pictures of your ranger anywhere?