okay...one more ? about brakes

[redhot91]

91 has 4 brand new calipers, rotors and ceramic brake pads. Why does my Reatta still sound like the calipers are hanging up? When I drive through a parking lot without applying the brakes I hear "squeak, squeak, squeak, squeak" coming mostly from the rear tires.

The brakes do feel a bit more spongy than I would have expected from a non-teves system. The lines have been bled twice since the brake job. The 91 doesn't have all the fuss with an accumulator (we had a 1990 and learned all about the headache Teves) So what did we do wrong with the brakes? Is there some other problem not related to the brakes?

thanks again!

[Reatta45]

New calipers? were they ?loaded? calipers? Or did you assemble the ceramic pads, in them? Did you use anti squeal adhesive behind them? How did the wheel bearings feel while everything was apart? Is the park brake activating lever all the way to the rear against the stop? If all these questions don?t come across a problem, I can not figure what your trouble could be? having recently replaced pads on my 91, everything worked out great, no problems. KennyV.

[redhot91]

I didn't use the loaded calipers. I did place the anti-squeal on the back of the pads. Ahhh...but I didn't check the bearings. What should I be looking for when I inspect the bearings? Do you think that would be causing the awful "record playing" on the rotors?

I've also suspected the pads are crap or the rotors could be off just a hair. I hate to think that because that would mean tearing it all off the Reatta, taking it all back to the parts store and starting again. *sigh*

[Reatta45]

Your wheel bearings should hold the hub solid with NO run out? Jack up the rear and holding the tire at a position around 12 and 6 o?clock pull top and push bottom, also check at 9 and 3 o?clock should be solid without any give. You can see the rotor between the spokes on the wheel. If wheel bearing is worn it can let the hub cock slightly. Wheel should turn free.

I myself don?t care for ceramic pads for street use? They can take a long time to seat to the rotors, especially the rear with less pressure at calipers this may be the problem you are having. If so it will improve with use. KennyV.

[Guest EDBSO]

Some brake "bedding" tips here.

[Shelby]

With the loaded calipers you get the right hardware to make the brake sound and work properly.

I don't like ceramic pads. They are to hard and noisy.

I use the cheap one and change them more often.

[Barney Eaton]

Somethimes us shadetree mechanics forget small details. When you work on the brakes, you have allowed the rotor to move from its original seating. This is critical on vehicles that are not "virgins" and have had the little spring keepers removed from the wheel studs.

When you disassemble the brake, dirt and rust can fall between the hub face and the back side of the rotor. A small amount of rust can cause the rotor to now to have radial run-out.

If you want to do a great brake job. Remove the rotor, clean the back side and clean the hub face (this is the hub with the studs) Wire brush both. I usually then wipe them with oil to help stop any new rust from forming. Now install the rotor. Install at least two lug nuts to hold the rotor firmly against the hub. With a dial indicator, check the run-out as you turn the rotor. Ideally you should have no run-out but a street car can live with .005

If you find you have more. mark the high spot. Remove the rotor and index it half a turn. (with 5 lugs your choices are 144 or 216 degrees) Repeat the indicator check to see if it improves. You might also want to double check the back side of the rotor for a flake of rust in the area of that high spot.

If and when you get the rotors running true, you will not get the "Rub...Rub...Rub" because they are now turning true.

[Roadster90]

Another excellent bit of advice / instruction from the forum via Mr. Eaton...thanks

[manikmekanik]

"New" rotors are not always true.

Like a 33rpm album, they need to be stored on edge, many parts vendors store them on thier face, horizontally. I get my parts store to turn them down to the point they are true - for free, insuring I don't have to bring them back later.

Also, check your rear caliper mounting brackets, if worn at caliper mounting holes, or cracked at backing plate mounting holes, they can cause the same conditions, or worse. If they are bad, pulsation will also be noticed upon braking.

Barney, Thanx for revealing the simple steps in the process all experienced diagnosticians use consistantly. Most of us neglect to mention such mundane details we've always used while explaining the "hard stuff" involved in brake system maintenance which others do not understand.

Just like service manuals, we sometimes assume a certain level of basic knowledge and skill is understood BEFORE asking for advise with advanced systems' problems.

Your insight and technical input will always be welcome here. Thanks, again!!

[Guest EDBSO]

<div class="ubbcode-block"><div class="ubbcode-header">Quote:</div><div class="ubbcode-body">"New" rotors are not always true.

Like a 33rpm album, they need to be stored on edge, many parts vendors store them on thier face, horizontally. I get my parts store to turn them down to the point they are true - for free, insuring I don't have to bring them back later.</div></div>

Thanks for the tip. I would not have thought of turning the rotors first.

Some Brembo information ... a casting from a Brembo foundry that assures uniform thickness, Brembo OE Replacement Brake Rotors are machined to exacting tolerances (the rotor run-out tolerance is only 0.0025?, about half of the industry norm), feature a braking surface finish (ground or fine turned) compatible with the vehicle?s OE specifications and are electronically balanced to minimize the possibility of vibration.

[redhot91]

Thanks to everyone. Many interesting points I never considered while doing something as simple as brakes. The rust on the hubs and of course my suspicion towards the rotors not being "true." The exact same sound is emitting from our Explorer brakes (which also got a new brake job with the works all the way around.) The '00 Explorer (140,000 miles) emits a sound at the end of a stop that sounds like a seal (yes, the large aquatic sea mammal. ) We've learned to live with marine life under our wheels.....now, I am thinking we now may be on the right track to fixing both brake issues thanks to the advice we got in this post.

I'll give an update after I tackle some of the other major problems that just surfaced with the Reatta. (please see my newest post "The Wicked Wrath of the Auto Gods")

Thanks again!