Brakes Pulsing

[milradioman]

This started a couple of weeks ago and I cannot find any reference like it on this site; when I apply the brakes, I hear a pulsing sound only on the last few feet as I come to a stop, it sounds like the ABS system activating from a slipping wheel but I don't feel it on the brake pedal. I hear it only when the brakes are pressed, it feels almost like running over the rumble strips on a highway, the pulse frequency is related to the wheel speed. The ABS bulb passes the light test on start up so it is working, but the light does not come on to indicate a brake issue. Anyone have any ideas what this is?

 

[joecool911]

Warped rotor? I had a rear rotor that pulsed especially going downhill and braking hard at hiway speed.

[flagmanruss]

Ditto.  I had a warped rear rotor.  The shop I used couldn't find it but charged me plenty each time.  I took it somewhere else & they replaced one rear rotor, problem solved.   

[joecool911]

I got cheap rotors. Only $35 each and that's even with the parking brake shoe surface. Can't believe how cheap. Local auto parts store.

[Ilikeoldfords]

This started a couple of weeks ago and I cannot find any reference like it on this site; when I apply the brakes, I hear a pulsing sound only on the last few feet as I come to a stop, it sounds like the ABS system activating from a slipping wheel but I don't feel it on the brake pedal. I hear it only when the brakes are pressed, it feels almost like running over the rumble strips on a highway, the pulse frequency is related to the wheel speed. The ABS bulb passes the light test on start up so it is working, but the light does not come on to indicate a brake issue. Anyone have any ideas what this is?

Do you just hear the pulsing?? Or do you actually feel a pulsing as well? If you are just hearing it then I would pretty much rule out the warped rotor idea. You might try checking the codes with a good scanner. Not all of the codes will turn on the dash light for the ABS or the regular check engine light. There might be a code hiding in there that would tell you something.

[milradioman]

It does not feel like a warped rotor, I hear it but dont feel it in the brake pedal, it sounds like it is in the front axle area(?). I tested by braking hard in the snow coming to a stop and felt the brake pedal push back when the ABS started working. it is a sharp pulse very much like like the ABS pulsing but consistant and pulse frequency changes as the wheels slow down. I have a friend with a code reader, I will check for any codes.

Brian

[Ilikeoldfords]

I have heard of some weird things happening with the ABS pump. I think rancherman had some issues a while back about it just running continuously on its own. The module can go bad causing these issues I think.

You might unplug the ABS module and see if the noise goes away. If it does, then you know something is making the ABS pump run for some reason. We can then go from there and track down the issue.

[MnTom]

That sounds more like a bearing problem rather than an ABS problem.

[CTcummins24V]

X2 on the unit bearing/hub. Jack the front up, grab the tire at 12 and 6 and try to rock it back and fourth

[TFaoro]

X2 on the unit bearing/hub. Jack the front up, grab the tire at 12 and 6 and try to rock it back and fourth

If you aren't sure if you are strong enough, stick a metal bar under the tire at an angle and lift up and down. 

[CTcummins24V]

If you aren't sure if you are strong enough, stick a metal bar under the tire at an angle and lift up and down.

The up and down motion is to check for bad ball joints. The in and out motion (to and from the truck) is for bearings

[TFaoro]

The up and down motion is to check for bad ball joints. The in and out motion (to and from the truck) is for bearings

That is why I suggested at an angle. If you have the bar only touching the outside edge of the tread when lifting it will pull the bottom of the tire out. That is how I was taught and I have found 2 bad bearings that way 

 

That being said, if you get the bar underneath the tire and have most of the tire touching the bar & it moves up and down then the ball joints are worn. 

[milradioman]

Had not thought of a wheel bearing, I probably should have not driven where I did yesterday.

The "pulsing" could be each of the bearings clunking as they turn.

I will perform the tire thing; attempt to move the tire in a rocking motion not a up/down motion as I understand it.

Either way if it moves I have some work to do; bearing or ball jount, I just replaced the track bar joint, so would surprise me if the others are going.

 

Assuming the problem is bearings (sounds like the problem); what are sources of good quality bearings? I dont want the cheap China stuff, I like doing it right the first time.

I have heard the bearings are a sealed "pack" how easy are they to replace? And is there anything else I should replace while I have it apart?

 

I appreciate all the input.

Brian

[joecool911]

Buy US made hubs. Timken produces some. I would not get NAPA brand for instance. Unless you are pretty advanced mechanically, you'll need to buy whole new hubs. If we're talking front 4 wheel drive. About $600 for 2 new hubs I believe. 2 wheel drive is much simpler and cheaper.

[MnTom]

2 wheel drive is much simpler and cheaper.

Way simpler and way cheaper, but I have 280K miles on my original bearings. That is because you can pull them and repack them.

[joecool911]

Is it realistic for the average Joe to modify a new set of hubs to include grease zerks?

[moostang]

When my bearings went bad I had very little warning, just a squeek every now and then.  They were so bad I could hardly turn the tire with it jacked up.  I got everything from Rockauto, Timkin bearings new ball joints, u joints.  It was a fairly big job. The bearings were easier than the ball joints.  There are some good threads here to help.

[dripley]

Is it realistic for the average Joe to modify a new set of hubs to include grease zerks?

 I think it was Diesel4life that did that very thing. If not him, someone here did it.

[milradioman]

I heard the bearing is a set or pack that is sealed and cannot be rebuilt, I suppose anything could cut into and be rebuilt, I am interested if it can be done reasonably.

[CTcummins24V]

If its a 4x4, you need to buy the whole hub unit assembly