Well crap... After I have been singing such good praises about my truck, it has let me down a bit. I jumped in it today after work to warm it up so that we could go pick up 2 pallets of rock/wool insulation from Home Depot.

As soon as it fired up, the brake pedal started pulsing very quickly when I was applying the brakes. I let it warm up for 10 minutes or so, then checked the pulse in the pedal and it was the same. Thinking it was worth a shot, I shut it off and turned it back on again, but still the pulsing and noise was there.

I checked the power steering fluid and it is full. I checked the brake fluid and it is full. I took a quick look at everything paying special attention to the pulley on the power steering pump, and everything looks and sounds normal. No fluid leaks under the truck and nothing out of the ordinary.

The brakes did clear up a bit it seems, or maybe it is my wishful thinking, but still pulse rapidly and make the sound in the video when pressing hard on them. You can hear the pulse sound when turning at low speeds as well, but I cannot feel it in the wheel.

My initial suspects are the power steering pump or the hydro-boost system. The problem is I don't know much about either one of these systems, so which may be failing escapes me. Maybe the problem is another system or part I have not even thought about?

I was hoping that some air was trapped in the system from the recent steering gear replacement and the cold temperatures we have been having caused the hydro-boost to throw a fit and it would work itself out. 30 minute round trip and some idling at the Home Depot did not change the symptoms. I did bleed the system very well though ensuring all the air was out I could get to when I changed the steering gear.

I am open to ideas or suggestions before I tear into it.

I do have to have this resolved before our upcoming camping trip, or SC gets to keep my $350 for nothing...

Updates to the thread title and video description once the issue has been taken care of.

Any input or insight you may have is appreciated, thanks.

 

I don't v think its power steering unit or you'd never make it to Depot. My money on ABS, but would start with hydroboost...easy to get to/replace...make sure you get a few of them white plastic collars/crush washer fir the power steering line...

 

My truck doesn't have ABS, so that is out...

The sound is present when turning the steering wheel at slow forward speed without applying the brakes, so this is why I was leaning toward the power steering pump. Maybe your right though and the power steering pump either works or it doesn't and since we made a 30 minute round trip journey, the pump is fine.

In regard to the hydro-boost, I am having a hard time finding the right part. At Rock Auto if you search for hydro, the brake cylinder comes up like in the second picture.

Does this look right for the possibly faulty hydro-boost?

More Information for MOTORCRAFT BRB33





Or, is this the part that may be causing the issue?

http://www.rockauto.com/en/moreinfo....sn=488&jsn=488

 

In addition, I am seeing the failure of the hydro-boost being a very hard brake pedal which is not anything like I am experiencing.

 

Sous, I'm leaning toward the PS Pump because you state you hear it when turning. Have you tried taking a piece of hose to the pump and the other end to your ear, then have the wife push the brake pedal. Also have her turn the steering wheel. You could do the same thing on the hydroboost. You'll be able to hear the sound to the hose.

 

First picture is the hydroboost.

Quick question, how old is the brake fluid and the atf in the power steering pump? These are both hydraulic systems, and bad or worn out fluid can cause all sorts of issues and noises.

 

I do hear the "pulsing noise" when turning the wheel at slow speeds. But, I also hear it when sitting still and pushing on the brakes, like in the video. The pump does not whine or make any other noise. This pulsing noise and sensation caused by steering and/or applying the brakes is new. Maybe the cold weather had something to do with it, or maybe it was just a coincidence.

Not sure what you mean by hearing the sound with my wife at the wheel, I imagine I won't be able to hear much of anything next to the engine.


Brake fluid is 3ish years old and clear looking in the reservoir. The brake pedal is firm, not mushy or going to the floor at all. The ATF in the power steering system is pretty new synthetic. I replaced the steering gear and 90% of the fluid in February of 2016, then some again in October of 2016 due to the new steering gear failing.

I am thinking that I will try and bleed the system again with the instructions from Trey as a last ditch effort to fix the problem easily and quickly.

 

I have no idea if it can apply to your situation here but...I had an issue last summer where my pedal would intermittently pulse when brakes were applied, cruise control would flick off when I ht a bump and I'd have to reset it. Then my ABS light came on. I got under the truck thinking that I was going to replace the speed sensor in my rear but I found that the connector was not on tight. Pushed it on and problems solved.

 

Mark, cruise control works fine. Activates, holds speed and cancels with the tap of the brake.

The brake pedal has no pulsing unless I push 1/3 the way down or further and the noise is barely audible when turning at low speed.

I am pretty sure my truck does not have ABS because the wires are cut off at the hubs for the sensors. In addition, the noise happens when the brakes are not applied and turning only.

 

Take a piece of hose 3' long, put one end on the ps pump and the other end to your ear, have your wife turn the steering wheel. If the pump is making noise you can't hear over the engine you'll hear travel up the hose. Hopefully that's clear...

 

So basically I am trying to find the source of the noise using the reverberation of the part up through the hose?

 

 

Be back in a few minutes, going to try this on the power steering pump and the hydro-booster.

 

Long shot. Have you look into the power steering reservoir to see if the fluid looks aerated?

 

Poor man's stethoscope works good. A long screwdriver with a plastic handle can work to. Wood handle dampens the noise.