Brake Master Cylinder Issues

[BadlyBent]

I recently replaced all 4 brakes with discs. Had problems for a while with "double pumping" the pedal to get the truck to stop. Well that resolved itself to the point now that double pumping no longer helps and stopping power is diminished. Tried bleeding again to no avail. I've noted the rear fluid reservoir has turned brownish and seems to be losing fluid. I assume my master is failing. The brake cylinders and fittings show no signs of leaks.

I read several threads about replacing the original master with an FJ80 cylinder and bought one online. I wanted a master that was designed for discs anyhow.

My dilemna now is how to get the rear line off the master. The front line was tight but was able to remove it. The rear won't come. I have tried heat and penetrating oil (but haven't waited particularly long...).

Since I'm already committed to this thing (bought the FJ80 master) would appreciate comments from those who have done this before.

Mark

 

[trekker]

Got a little rust eh? Go slow. Gently turn the nut with the wrench. To the right and left. Just push a little in each direction. You want to break the bond.

Try not to round the head. If you do, try vice grips and chinch them down and twist in both directions. Littel pb blaster between tries. The line might be rusted to the fitting as well. If this is the case, cut your line close to the fitting and stick a socket on it. Gently and firmly turn a little each way.

If you mess up the line and fitting, all you need to do put on a new fitting and reflair the line.

 

[Moe R]

Loosen the master from the booster. The masters are installed loose and tightened up after the brake lines are attached so threads
don't cross or bind. Use some blaster but give it a chance to work in. Best of luck to ya!

 

[dgangle]

And make sure you are using a line wrench.

New JH Williams Metric Flare Nut Line Wrench Set 9-17mm - eBay (item 120206341071 end time Jan-13-08 19:02:00 PST)

 

[BadlyBent]

Thanks for the advice. I did recall that rounding off was a bad thing so I've gone slow. Having read the postings on the challenges of flaring, I'm a bit anxious to cut the line. This may turn into a multi-day affair. I am using the PB blaster and appreciate the referrence to the line wrenches - new to me (I'm a bit slow, self-taught, inexperienced and prone to fits of impotent rage when things don't go as advertised...).

Thanks!

Mark

 

[Doug_S]

And make sure you are using a line wrench.

New JH Williams Metric Flare Nut Line Wrench Set 9-17mm - eBay (item 120206341071 end time Jan-13-08 19:02:00 PST)

Line wrenches are sometime called tubing wrenches.

 

[Moe R]

Loosen the nuts to the Boosterand you'll have some wiggle room. X6.325 on the line/tube wrench. Copiech