Failing hydroboost

[OregonDMAX]

I have a weird pulsating sound coming from my brakes when I apply them and I can only hear it below 5mph to a stop as soon as I let off the pedal its gone. No vibration though.

What are some signs of hydroboost going out. The brakes still work decent but its hard to tell how much better they could be unless i threw parts at it.

What do ya guys think.

 

[Hot COCOAL]

I have a weird pulsating sound coming from my brakes when I apply them and I can only hear it below 5mph to a stop as soon as I let off the pedal its gone. No vibration though.

What are some signs of hydroboost going out. The brakes still work decent but its hard to tell how much better they could be unless i threw parts at it.

What do ya guys think.

I don't have an answer, but you know I have a hypothesis
I believe its just the system pressurizing? The rubber lines flex and so the sound you hear is the vacume in the system releasing and the squishy feel you get on the pedal is the "pump" getting the system to a pressurized and ready to apply force potential...I say this because it pretty much went away on my truck when I went to stainless braided lines...

 

[Awenta]

Usually kickback or it leaks from the weep hole where the master cylinder is bolted to the hydroboost.

Sent from my SM-N910V using Tapatalk

 

[OregonDMAX]

I don't have an answer, but you know I have a hypothesis
I believe its just the system pressurizing? The rubber lines flex and so the sound you hear is the vacume in the system releasing and the squishy feel you get on the pedal is the "pump" getting the system to a pressurized and ready to apply force potential...I say this because it pretty much went away on my truck when I went to stainless braided lines...

Well It just started doing it, and I did stainless lines about a year ago. The pedal feel is normal I only hear the sound.

 

[jliddle]

Hit the pedal quickly, if it kicks back then the hydro boost is going.

I know Ben put a 2011 unit in his and it was a direct bolt in. Only LMM and 2011's will work from the LML trucks due to a different sort of brake pedal electrical issue IIRC.

 

[ikeG]

Sure it's not the dirty/bad speed sensor symptom where ABS kicks in under 5mph?

 

[Robby05]

Wheel bearing?

 

[OregonDMAX]

No vibration just sound only. It shows up as soon as I hit the brakes at low speed and goes away as soon as I let off the brakes if I hit the brakes right away again its back. Unless it's something in the abs I'm thinking it has to be the hydroboost.

 

[Chevy1925]

Have your brother listen under the hood or you do it. You may be hearing the power steering pump pressure valve popping open for some reason. Either way, you should be able to hear were its coming from under the hood then

 

[oh05ext]

my 2004 does it. im guessing its the abs, pull the abs fuse and drive it. if it goes away found the problem

 

[OregonDMAX]

I figured mine out its definitely the hydroboost. You can feel when it's abs this is completely different.