Hi there,

New to the forum here. Sorry if this is posted under the wrong category.

My sister owns a 2003 Disco 2 which I have been doing some of the maintenance on.

The car started to get a brake pulsation around a year ago, only in the pedal. Within the next few months it gradually worsened.

So last fall I replaced all the rotors+pads (front and rear), since the front were worn out anyways. The pulsation did not go away at all, even directly following the brake replacement.

When replacing the discs I cleaned the rust off of the hubs the best that I could (I thought it was sufficient at the time). Where I missed was because I do not have the tool designed for cleaning hubs with wheel studs, the one that slots over the studs (mainly work on BMWs). I have done the brakes on my moms range rover sport, as well as my other sisters Wrangler, where I experienced the same problem of not being able to fully clean the hubs and had no issues there at all. Obviously there is about a 15 year age gap between the cars though - the hubs on the Sport+Wrangler were a lot cleaner to start with.

Before I replaced the brakes I was sure that it was a warped rotor, as most would think with the described symptom. Now I am not so sure.

There is a possibility that the remaining rust on the hubs caused an uneven surface, mimicking a warped rotor? The only reason I find that hard to believe is that one would think there would be a somewhat even amount of rust around each of the studs. I find it doubtful the slight variation would be enough to cause such a massive vibration right off the bat, but you never know.. The other reason I find it doubtful, at least from my experience when the hubs are not cleaned properly during a brake job it usually takes a little bit of time for the vibration to come back. Usually a couple weeks/months not instantaneously, but again maybe I am wrong.

The only other things I can think that might be causing this issue would be something else that is warped, like the hub itself. I have never personally seen or heard of this happening though. Further in possible a wheel bearing? You would think there would be many other signs of a wheel bearing failing that badly before it was showing through the brake pedal though, none of which I have personally experienced.

Then lastly possibly the ABS kicking in? The only reason I have to doubt this is that when I have experienced the vibration in her car, I did not hear the ABS kicking in. Bear in mind I don't think I have ever actually stopped hard enough to engage the ABS under normal conditions, so I don't exactly have a control to compare with but I would imagine it would be pretty loud like in most cars.. I guess an easy way to check if its the ABS is to pull the fuse for the pump?

If anyone has some ideas or opinions that could chime in that would be much appreciated. I am really trying to avoid replacing the discs again if that is not actually the cause of the issue.

 

You don't mention cleaning and greasing the caliper guide pins...

 

Sorry I did not mention it but yes I cleaned lubricated the guide pins. If you'd like the full story: one caliper (right rear) had a leaking piston seal and it was professionally rebuilt, the other three were fine. Before reassembling I checked that all the pistons moved freely, and the guide pins were moving freely. The brakes were completely bled afterwards (all four calipers out of precaution), I did not activate the bleeding procedure with the ABS but I do not think that is necessary given the air got in right at the end of the system. I would think I more than likely would have gotten away with bleeding just the one caliper that was off. It was plugged during the rebuild time and I allowed it to gravity bleed with the nipple open as well once it was reattached so that it would not be completely full of air. No other parts showed any signs of faults other then the one leaking caliper as well as the inner brake pad that had gotten wet with brake fluid. Aside from that they just looked like worn down brakes, no other causes for concern. I mentioned the three brake jobs I've done on cars with studs, but I should mention I have also done countless brake jobs are cars without wheel studs. So I am well aware with the procedure. As I mentioned as well there was no difference in the pedal feel from before and after.

 

Did you try rotating the tires? Sometimes, you may have a seprarated belt or ply or poorly balanced tire and it shows up during braking. And sometimes the vibration of a bad tire will be enhanced by old wornout shocks and coil springs. Check all of your steering components also, ball-joints, drag-link, tie-rod ends, steering stabilizer shock, etc. It's not that uncommon to have vibrations show up under braking events, since everything associated gets stressed...trying to stop the vehicles forward motion.

 

Inadvertently yes: When I changed the brakes, I also switched the car onto the winter wheels+tires. They were some brand new aftermarket wheels and new blizzak tires, so it doesn't seem like the problem could be with tires/wheels in this case. That is also a good point with the suspension, I will definitely give the suspension a good look over and try to check for any play.

 

I think you need to replace your front hubs

 

Why the front ones specifically? I was always taught that brake shudder/vibration in the pedal generally indicates its coming from the rear brakes/wheels whereas if it's in the steering wheel it indicates front brakes/wheels. Maybe this is totally wrong or does not apply with these cars? Is there anyway to check the hubs before replacing?

 

I had the exact same thing happen a few months back. It was the front drivers hub.