Series front brakes

[Roverlass]

A little history, our 88" was converted to power 109 11' front brakes approx 10 yrs ago.. Stopped so hard you needed to beware of the steering wheel with front teeth. Over time and a replaced master cylinder, brakes are as bad or worse than the original 88 10" brakes. replaced all wheel cylinders, brake shoes etc on front, still anemic. replaced power vacuum unit. through hands up in air, replaced front brakes with Torrel disc brake set up. still anemic. thought maybe brake lines to master cylinder in backwards (88 vs 109). switched lines on master cylinder, made no difference. ideas?

[ANDYD]

One way to trouble shoot is to clamp the flexible brake hoses using clamps or vice grips, this will isolate part of the system. (Left front, right front or rear axel) If the brakes improve when one part is clamped you know that the clamped off part is the problem area.

So many things can cause sloppy brakes on a series truck you need to narrow it down.
Good luck

[TimberPig]

Have you checked or changed the flex lines?

I have heard of more than one case of deteriorated flex lines that looked good on the outside, but had become so constricted inside that little to no fluid can move inside to activate the brakes. The pedal will feel good due to the resistance, but not be activating the wheel cylinders. Newer flex lines are reportedly worse for this as well, so no guarantees that new lines are good.

Given this developed over time slowly, and has followed the mc and front disc swaps, plus no external leaks, leads me to think there is a blockage in the lines.

[Roverlass]

TimberPig,
Great idea. however, I replaced the hoses when installing the Disc brake conversion. Am in the process of changing out the master cylinder and will update tomorrow.

[TimberPig]

In that case, starting with ensuring the master cylinder is functioning is a good bet. Once it is confirmed good, then continuing downstream ensuring the lines are passing fluid and checking correct function of the rest of the system can continue.

[HeadDamage]

Are the shoes on the right way round and properly adjusted?

[Roverlass]

Replaced the master cylinder, Much better. still not the windshield in your face I was hoping for with the Torrel disc's up front. Still not wanting to tow a medium size trailer ,<2500# s> till I get it really dialed in. Hoping the pads seat soon and brakes improve. Feel better about going up to Van Duesen now.
Ian

[bsa_m21]

Have you installed residual valves in the lines? Many retro fit systems recommend them. They keep a little bit of pressure in the line after you release the brakes. Seems to make the brake pedal action a bit stronger. You can find them at https://www.wilwood.com

M