Wonky hydroboost

[DoubleO7]

Well, it acted up again this morning. Just once, briefly, and I was only going about 5 mph. A new OEM brake booster is now on order. Amazon price is $467 plus tax, roughly double what the O'Reilly remanufactured booster cost me. Free shipping, and it should arrive by Friday.

Did they refund the remanufactured unit?

 

[MarkB_MI]

Did they refund the remanufactured unit?

Did they refund the remanufactured unit?

I haven't taken it up with O'Reilly. Yet.

 

[flying belgian]

A couple weeks ago the brake booster on my 2017 Chevy 2500 Duramax started leaking, so I replaced it. A new AC Delco booster is over 500 bucks, so I opted for a reman unit from O'Reilly for $210. Since replacing the booster, my brakes MOSTLY work OK, except when they don't. Every so often, maybe once a day, I lose boost and have to mash down hard on the brakes to get stopped. It only happens once, then the brakes are fine on the next stop. Initially I thought there was a little air in the system that would eventually work out, but I'm beginning to think the reman hydroboost unit is defective.

Is it possible this problem will clear up, or should I bite the bullet and replace the reman hydroboost with a new OEM unit? We're taking our fifth wheel camper on a trip in a few weeks and I need to get it resolved before then. It scares the bejeezus out of me just stopping the truck with no boost and I sure don't want this to happen pulling the camper.

I know nothing about your system but on my old f-600 one time it was acting like that. Sure seemed like the hoses were collapsing but they weren't. I replace the diaphragm one time and the whole booster twice to no avail. As a last resort I replaced the hoses and no problems after that. The hoses were separating and collapsing on the inside.

 

[MarkB_MI]

I know nothing about your system but on my old f-600 one time it was acting like that. Sure seemed like the hoses were collapsing but they weren't.

This is not a vacuum system. The hoses are all under pressure.

 

[flying belgian]

This is not a vacuum system. The hoses are all under pressure.

Even under pressure maybe there separated inside and screwing things up. Something to consider.

 

[Sprint 6]

Even under pressure maybe there separated inside and screwing things up. Something to consider.

Power Steering hoses have a steel expander inside them to keep them from collapsing.

 

[MarkB_MI]

Even under pressure maybe there separated inside and screwing things up. Something to consider.

Even under pressure maybe there separated inside and screwing things up. Something to consider.

Perhaps. But everything was working fine until I replaced the original booster with a remanufactured unit. (The original was leaking.) And it's working fine again after installing a new OEM booster. (Knock on wood.)

 

[504]

Apparently I spoke too soon. After four days of no problems, the booster started acting up again when I was stuck in a traffic jam. I first noticed the smell of hot hydraulic oil, then several minutes later I started losing boost. I realized then that the problem only happens after driving in traffic for a while. The problem cleared up immediately as soon as I got out of traffic, presumably because of air flowing over the power steering cooler.

Either there's still air in the system, or the fluid is contaminated. I'm going to flush the fluid out, which is quite simple on the hydroboost. There's a return line that goes from the booster to the PS reservoir; you just take that line loose and replace it with a long hose going to a drain pan. Then exercise the system. Whether the problem is air or contamination, flushing the fluid should fix it.

Why am I seeing this problem after the booster replacement? My guess is the reman booster is generating a lot more heat than the old unit.

On the GM hydro boost systems the power steering pump requires a special oil. That was on the old square bodies. Transmission fluid would eat up the seals in the booster. Just trivia.