I have been trying to solve a moaning front brake issue with my 94 xjs. So far:

Replaced caliper twice
Replaced rotor
Replaced pads twice
Replaced hoses
Bled brakes several times
Repaced Accumulator ball

Still moaning on the front left side where it always has. It happens just as the brake is being disengaged or engaged. Right at the point where the car starts to roll. It is not subtle. The entire car shakes and it is very loud. It only on the left front side.

It operates fine but is annoying enough to not want to drive it. I'll take the Toyota to avoid dealing with the issue.

My next step is going to be to replace the entire braking system. It is Teves III right now.

 

Possible wheel bearing going bad?

 

Another vote for wheel bearing, or even brake shield which is prone to getting flexed just enough to touch disc.

Paul

 

I agree. Replace wheel bearings.

 

yeah if you replaced the entire caliper, i would look elsewhere. If those bearings are toast they can shift around and cause a shimmy. At higher speeds the level themselves out like a motorcycle

 

It appears like brake fluid is leaking on the caliper. Possibly coming from the seal between the res and the master cylinder. I though this was the hose but after replacing the caliper and hose it is still leaking... right on the rotor. There is a drain right above it, so it appears. I have to look in there during the day.

 

What pads did you use, and did you seat them properly?

some brands (like EBC) have a seating compound attached, others require a particular method to properly transfer materials form the disk to the pads.

I regret that I I have mind lapse and can't remember the procedure off hand, except that it entails driving to a certain speed and hitting the brakes hard a few times.

 

Moaning is gone.

After replacing the hoses and calipers and bleeding the brakes there appears to still have been some brake fluid that leaked onto the rotor. There was a puddle around the front tire... I'm unsure of whether this was spilled from bleeding. It does not seem to be losing fluid anymore...

The hose was definitely shot which was leaking onto the rotor causing the original moaning...

Anyway, something does not seem right given the size of the fluid leak but it has not leaked in two days... for now problem fixed. I'm hoping it was just a spill from the guy helping me with the bleeding...

 

I spoke too soon. Its back and like a rubbing moaning sound when I am stopping. if I keep my foot down on the btake and release slightly it just moans and vibrates the car. seemed like the caliper was sticking but I replaced it twice.

 

new wheel bearings btw. though, maybeI did not tighten them enough? the wheel does not shake at all. could it be a bushing?

The brief moment, I was able to drive this car in the 4 years I owned it without a moaning brake was a good moment. I realized it something I have to fix. Coming to a stop in the city with all the lights and trying to press the brake right to prevent the moan is just too frustrating.

Any more thoughts on this? Its been a while since I replaced the front wheel bearing. About 3 years. I cant recall if I replaced the inner, outer, or both. So I am ordering new inner and outer wheel bearings as we speak. Could it be something else while I'm in there? I was thinking previously it was the actuator. Could that cause this? Its been tested and all the solenoids clicked fine with 12v applied to them.

addendum: The moaning and shaking happens downhill and flat but not uphill.

 

Less weight is on the front going uphill

If you are already ordering the wheel bearing, lets fiddle with that and then worry about any other possible issue with the brakes.

The wheel bearings could be doing this, or they are not properly adjusted, the rotor could be moving slightly or become crooked. This would caused brake judder and vibration, which is what causes noise. This could have been an issue caused by incorrect tightening procedures from a while ago, that just developed to be noticeable now, with rotor and pad wear becoming worse and worse over time. Or the bearings could have gone bad from defects, lack of grease maintenance, or many other things.

You have replaced the calipers several times, so I would rule it out.

If you don't have a dial gauge but have a torque wrench, which you should if you plan on putting the wheels back on, there is a general method that works pretty well if you don't have the gauge.

1. While rotating the hub/rotor tighten the spindle nut to 25 ft lbs. It is very important to spin it while doing this. this seats the bearings and gets everything straight
2. Back the nut off 1/2 turns
3. Spin the rotor about 1/4 of a turn.
4. tighten the nut to 2 ft/lbs or 24-28 inch pounds
5. Insert cotter pin
6. grease it up
7. Rotate the rotor a bunch, it will throw a bunch of extra grease out. Get it now instead of making a mess of your wheels or getting it on the rotor when you are driving.

 

Good to check/replace/repack/adjust the wheel bearings as needed.

But.....

Let's talk more about this moan.

Is this the type of sound you can get from the brakes on most any car if you come to a stop with the brakes just lightly applied? Or, if sitting at a stop, very slightly easing up on the brake pedal so the car just barely moves forward....accompanied by the brakes moaning or groaning?

Is that the kind of noise you are referring to?

If so, go back to the earlier post about the type of pads if if they have been bedded in. I'm wondering if the pads and rotors have glazed.

Or, even if not, the previously reported brake fluid leak may have migrated onto the pads....and ruined them. Contamined pads will often be noisy and grabby....

Cheers
DD

 

I already torqued the wheel bearing to proper spec and adjusted correctly. I am just at a complete loss so I was going to do it again. I am repeating myself at this point. The other wheels are all ok.

The first thing I did to remedy the problem was replace the rotor and pads. Instantly I got the same moaning sound.

I am also looking for parts to replace the entire braking system as it is possible that it is not releasing all the way due to the actuator design. Though if this was the problem I was thinking it should do it uphill as well? Maybe not.

 

One more idea, For some reason, these cars seem to wear the spindle where the inner race of the rear bearing fits. An apparent result is that the bearings can n loger be properly adjusted, even if they seem to be.


My similar XJ wuzza six did that. No Teves, though to complicate things. a ggawdawfu noise, way past moan!!!


Fresh pads and a scuffing of the rotors fixed it.


Now, I left off the antirattle springs. No ill effects, of course my poor ears wouldn't notice it!!!


Now, when I did the front brake job, I found the ways badly crudded upa nd the pins equally cruddy. How can the things work that way??? I cleaned each and applied just a tab of high heat lube. That just might have been the key. Moan, bye,bye.


Now, as to bedding. I see it as a fine line between a good scuff and over heat with possible warping and glazing. I have always done just a few easy stops working up a bit from one or two to harder stops. But, never a lock 'em up!!!


Just after over four score of messing with these critters of many specie...


The Jaguar being amongst the most intriguing.


Carl