2008 F350 Front Brake Smell

[Blacktruckdave]

Hello Forum - 2008 F350 4x4 5.4l gasser
I replaced all 4 calipers about a year ago and put on new pads. I also replaced both front rubber hose brake lines and flushed the system with new fluid. System has been operating great until recently. I added new front Rancho 9000 series shocks and ever since I have been battling hot front brakes and the stinky smell that comes from it. The shocks are adjustable so I have tried different positions which seemed to help temporarily but then the smell came back again. I removed the drivers front wheel and inspected the pads. They look good so I cleaned the metal tabs and the slots they sit in on the caliper bracket and added some caliper grease. I also checked the caliper slide pins and everything looks and functions good. Put it all back together and 2 days later I am having the same problem.
Anyone have any experience with this problem and what other things should I look for? Thank you in advance.

 

[dustybumpers]

Your power brake booster is taking a poo

 

[Blacktruckdave]

I did the pedal press down test. Engine off and press pedal a few times till pedal was hard and kept pressure on it, then started the engine and the pedal went down.
Any other things to check. I looked over vac lines which all seemed ok.
Possible the caliper has just crapped out?

 

[dustybumpers]

I have a f250 that has done this twice.
It is a diaphragm inside the booster, and for some reason, it is leaking slightly on the master cyl side, and applying vacuum to the master cylinder.
This applys pressure to the brakes.
There is a relief valve that applies front first then rear [Keeps you from spinning around in circles]

If you unhook the vacuum supply to the booster, Block off the hose so you don't have a vacuum leak, and drive the truck, it shouldn't freeze up the front brakes.
Use caution when testing like this, you wont have very good brakes

Usually the diaphragm goes out on the pedal side, and you can hear it, as well as feel it fail

Sent from my SM-N960U using Tapatalk

 

[Blacktruckdave]

dustybumpers - What did you do to remedy this? Could it be a vacuum leak somewhere else? I haven't checked all the hoses yet. strange how it started after installing the Rancho 9000 series front shocks.

 

[dustybumpers]

I changed the booster
It's probably just a coincidence
I ment to say something when you did the brake lines before, but it slipped my mind

Sent from my SM-N960U using Tapatalk

 

[Blacktruckdave]

Update.... My driver side wheel hub bearing must have been on the outs and finally threw an abs code. Installing both sides with new Timkens.