Issues after WJ Master/booster upgrade

[superjay5ive]

Happy 4th! My day was going good, new waterpump and steering gear installed with no issues. Turned to the WJ Master/booster upgrade and ran into some issues.

 

I bought new 2004 WJ Master and Booster from Napa, both premium parts from them. Bench bleed the master and made the mods to the booster. Teenage son helped me bleed the system. I am aware of the additional step for the load valve. Got good fluid out of all corners. 

 

THE ISSUE. Pedal goes to the floor, which is concerning. I assume I still have air in the lines. BUT even more concerning is with the vehicle running as soon as I press on the brakes my idle jumps up, which I assume is a leak in the booster. No pedal pressure with truck on or off.

 

Taking the rest of the day off, I'll dig into it more tomorrow but was hoping you guys could point me in the direction i need to look into. Did I get a bad new booster? or maybe a bad new master?

 

Before this upgrade I changed out all the front brake parts and I did have working brakes. Was hoping the WJ Mod would give me a little better braking.

 

Thanks in advanced!

 

 

[pizzaman09]

Easy test would be to remove the vacuum line from the master and plug it off, then repeat your testing.  If the engine idle doesn't jump then you know the problem is with the booster.

[superjay5ive]

That is a easy good test. Gearing up to head into the garage, I'll test that first. Debating on going out and grabbing a mityvac to help with bleeding as I won't have a helper today.

 

I'll be annoyed if I got a bad new part, I know it happens a lot, but somehow I have been able to dodge that bullet.

[superjay5ive]

I plugged the vaccum line to the booster. Idle stayed consistent, so at this point i assume the booster is bad. I went ahead and pulled the master and put it on the vise to bench bleed again. It was full of air! So now I'm thinking maybe i got a bad master also? I bench bleed it good before I installed it the first time, zero air. So why is there air in it now. I would not think bleeding the brakes would get air back into the master? While bleeding the brakes the master never got low on fluid and I have zero leaks as far as I can see in the system......

[schardein]

My first thought was you did not bench bleed the master.  But I see your last comment, that you did.  

 

Finding air in it when you bench bled it again makes me wonder if the line connection at the master was letting air in.  Yes, you would think that you would see a fluid leak if that was the case.  I haven't done this swap myself, but I seem to recall that the master cylinder uses bubble flares rather than traditional double flares.  Do you know if that is the case?

[Salvagedcircuit]

I mentioned this to the last few folks who did a WJ swap. Make sure you check the booster rod length.

I did a WJ booster swap this past October. My brand new WJ cadrone booster was not adjusted to the master cylinder. I purchased (2) WJ cardone boosters from amazon and 1 from napa. I believe all of them were set fully recessed from factory.

I know, I know, that's a lot of boosters. The napa one went back because it wasn't painted, and I damaged one cardone booster because some brake fluid accidentally entered the opening during my first assembly attempt.

 

The rod was fully recessed and never even pumped the master cylinder because it was so far recessed. There's an adjustment procedure in a pdf I will try and link when I get back. Grab yourself a master cylinder measuring tool or a caliper and some reference gauge blocks.

[Big_Mark]

 

The rod length maters