Brakes self apply while driving, mod of Hydraulic Boost lines to blame?

[ChrisSmith]

A follow up on the power steering hose subject most of us are aware of.. I had the hissing noise back in July on my 2010 model (~40k miles) and pulled the plastic insert out of the high pressure line to the hydra-boost. Noise fixed. But just recently I ran into an event where my brakes began to self-apply while traveling on the highway, and eventually locked the truck up completely leaving me stranded on the side of the road. I had to pull the ABS valve fuse just to free the brake lines up and make it home. This symptom in the service manuals points to either contaminated brake fluid or also a restriction in the booster return line. I didn't bother to remove the plastic insert in the hose booster return hose, but this event has me thinking perhaps the added restriction on that side may have caused this event.

Just curious to know if others have been removing the plastic inserts as opposed to replacing the hose and whether any unusual events have occurred since. I haven't read any real reason on why they are there in the first place, however, I figure there must be a worth while reason as no company spends money for the hell of it.

 

[Jim W]

A follow up on the power steering hose subject most of us are aware of.. I had the hissing noise back in July on my 2010 model (~40k miles) and pulled the plastic insert out of the high pressure line to the hydra-boost. Noise fixed. But just recently I ran into an event where my brakes began to self-apply while traveling on the highway, and eventually locked the truck up completely leaving me stranded on the side of the road. I had to pull the ABS valve fuse just to free the brake lines up and make it home. This symptom in the service manuals points to either contaminated brake fluid or also a restriction in the booster return line. I didn't bother to remove the plastic insert in the hose booster return hose, but this event has me thinking perhaps the added restriction on that side may have caused this event.

Just curious to know if others have been removing the plastic inserts as opposed to replacing the hose and whether any unusual events have occurred since. I haven't read any real reason on why they are there in the first place, however, I figure there must be a worth while reason as no company spends money for the hell of it.

From my background as a hydraulic engineer at Cat; that plastic liner (Teflon type material) has a purpose. The purpose is to prevent the break down of the outer covering of the hose material due to fluid passage and or the fluid incompatibility to the covering material. I can tell you that the lining would not be added to the hose unless needed. This adds cost to the hose and most manufactures are trying to drive down cost so as to maximize profits.

I would suggest that you have the brake system flushed to remove any debris from the hose material in the fluid and replace the failed hose with a new one from Ram with the liner installed.
Just my very humble opinion.

Jim W.