Brakes

[Matthew K]

I'm having the hardest time with my front brakes. I just changed the rotors (WearEver) and pads (Bendix). They've been on for easily 1000 miles. The stopping power is worse than before, and when I come to a hard stop, they make a low rumbling noise. All the parts (except for the friction areas) were greased with high-temp grease, as mentioned in the manual. Any suggestions? Thanks!
Matt

[AZ Jeff]

We need a bit more information--what year XJ, and how many miles total on the vehicle. Also, how many miles since the last brake major overhaul?

[martin]

Yes, could you tell us when the last time you had the fluid changed and brakes bleed. When/ if you changed the rubber hoses.

[Matthew K]

Gentlemen,
I bled the brakes in April 2001. The rubber hoses as far as I know are original. I have 133000 on my 95 XJ Sport. Thanks!

Matt

[AZ Jeff]

I think it may be time to rebuild or replace some calipers, wheel cylinders, and most of all, replace ALL of the brake fluid with new clean stuff.

Diassembly and cleaning of the master cylinder would not hurt, once you are doing this level of surgery.

[Matthew K]

AZ Jeff,
Do you have any clue as to what might be causing this noise?Thanks.
Matt

[sidriptide]

did you go to a semi- or full metallic pad? i i had some noise after switching to semi-met once before...
mike

[Matthew K]

They are semi-metallic pads....

[AZ Jeff]

Let's get some more details--

1. is the "rumbling" from the front, or rear? Does it get worse/better with more brake pedal pressure? I guess I am trying to determine if the rumbling is related to brake issues, or something else.

2. you say the braking is poor. (Early XJ's are not known for real good brakes anyhow.) If I understand you correctly, the new pads and rotors actually made the braking effectiveness WORSE. That means that SOMETHING you did during the front end brake refresh made the system less effective. I would be looking for stuck caliper pistons, rubber hoses that are deteriorating internally, etc.

[Matthew K]

1. Yes, the rumbling is coming from the front, and only when the brakes are applied. It seems to get worse as I apply more pressure to the peddle-almost like a grinding noise.

2. The brakes don't seem to grab as well as the previous set. I did everthing from sanding down the plate where the wheel studs come out to lubing the slides on the caliper and the bolts. I have even lightly sanded the glaze off of the pads.

The passenger side caliper was hard to push back in when I originally changed these pads. I had to use a c-clamp to push a piece of scrap wood against the piston. I also ensured that while the master cylinder was off that no air got in the system. But there was no sign of leakage from around either caliper, and the hoses seem to be in pretty good shape.

[AZ Jeff]

This sounds like a tough one. It sounds like you did the right stuff as far as installing the pads.

At this point, I would be inclined to put on rebuilt calipers, and FLUSH the system of all old brake fluid. I suggest this because of the number of miles and age of the vehicle.

It will also bring one more component of the front brake system back to "as new" condition, and it's about the only thing you have not changed up front so far.

[Matthew K]

Jeff, sounds good to me. Thanks for the insight. Like I said, the fluid was changed 2 years ago. Some say to change it everytime the brakes are replaced, some say you don't have to change it unless you get water/air in the system. I'll look for rebuilt calipers this weekend, again if it doens't rain this weekend!
Matt

[XJTripp]

The rumbling seems like a warning flag. Could you have misaligned a pad on the pins or let it slip while reassembling? This would bend the new pad and lock one corner against the rotor. You still get some braking action but not good action. This happened to me once. I would take the pads off. Examine them closely and reinstall or install new if damaged. This is not just a fluid change, cylinder wear type of issue. This is a mechanical or installation problem.

[Matthew K]

Tripp,
I have the outer pads sitting with their "nubs" in the holes in the caliper. The clips on the inner pads are sitting all the way in the hole in the piston. The pins as far as I can tell are all the way through the caliper and bolted down. I've taken both sets of pads off multiple times and can't see any unusual wear on the pads or the rotors. The front brakes seem like a very simple mechanical system, but for the life of me I can't figure out why they're making this noise/okay braking.

[AZ Jeff]

I am not an expert on this, but I have heard that there are DIFFERENT rotors that apply to the various years of XJ's,and that they are NOT interchangeable.

Did you replace the rotors recently, and if so, are you CERTAIN you have the correct rotors?

[Matthew K]

AZ Jeff,
Yes, the rotors are new (changed with the pads). They are Bendix #141602 from Advance Auto Parts. The pads are #MKD477, semi-metallic.
Thanks.
Matt

[AZ Jeff]

Maybe someone who knows of the differences between the various rotors for the various years of XJ's can validate if this is a good rotor for use on a 1995. I am sorry in that I cannot.

[4wheelnjeep]

Sometimes when the rotors are turned or manufactured, if not done correctly, it also can make a rumbling noise. Kinda like the grooves on a record.