1988 B250 conversion van.

I'm hearing and feeling a noise that is coming from the front tires area.
I think it's the bearings, or the brake pads rubbing on the rotor.

I replaced the wheel bearings along with new rotors, and calipers, and pads, a while back.

The new rotors came with the bearing races already in.
Are the bearings a slip fit or press fit into the race?

When I installed the calipers I tightened the spring clip down as tight as possible. Was I supposed to do this?...or not supposed to do this?

Thanks much.

 

raise the front end and rotate the wheel by hand. Any binding noise should be apparent as to what is causing it. The bearings are not press fit anywhere when replacing the rotor. The axel nut should be tightened, as the wheel is spun until the wheel binds, then the nut should be backed off 1/6 of a turn before having the cotter pin installed to lock it down. The wheel should turn freely by hand with no side to side play. It is a good idea to replace the brake hose on those front wheels. After awhile the internal rubber hose will collapse and the caliper will not release, prematurely wearing the pads and rotors as brake fluid pressure will get through the hose but will not release when you take your foot off the brake.

 

I put new timken bearings on the races which came installed in the Duralast rotors. They were not a good match, and I had to replace the bearings and races within 10k miles.

Later I replaced the duralast rotors with brembo's. The bores for the races were machined improperly, and the outer race was spinning in the bore on one rotor. Also the races were machined too deeply and there was not enough adjustment to take up all the slack.

The Brembo's came with SKF races installed

Don't trust duralast rotors, nor the cheapo races which come installed in them.

Removing the races requires a punch a hammer and some dexterity. Installing them ca be done with a properly socket and hammer, but special tools exist to minimize the likelyhood of damaging it

 

could it have been an improper part that you got from AutoZone? I have used Duralast (Autozone?) rotors on a number of vehicles including a '94 B250 and my newer B2500 in the past 15 or so years ( probably 5 or 6 pairs altogether) and all have been OK. I have never had to replace the roller bearings, just clean and regrease the originals. When I replaced the rotors, I was careful to freely spin the wheels when everything is tightened up to see how they spin. I have never had a wheel that I thought was too loose or too tight as to give me pause to the repair, or have to be serviced again in a short period of time.

I have wondered about the cheap metal used in the rotor and the pulsations that they give on the brake pedal as they begin to wear. A GM engineer friend of mine always blames brake pulsations on newer rotors on cheap foreign rotors that have hard spots in the metal that make break pads pull unevenly when braking after the rotors wear some.

Is there more feedback on Duralast rotors from others on the forum?

 

This is where the race rested in the Duralast rotor. Granted the others were not as bad. This was not the race which was spinning in the bore.



The piece of grit was intentional to allow proper focusing

 

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Ok so, It's the calipers hanging up, not releasing.

I removed them, greased the slides. Backed the nut off of the spring clips hoping this would allow the caliper to slide easier. I also drained some fluid from the master cylinder (thinking I had overfilled it).

None of this worked. I still have the noise/rubbing/pulsing. The pulsing though, isn't when I break, it's when I'm not breaking. It's very smooth when I brake.

Also, the bearings are in great shape. After removing the calipers I did back the nut off to free the bearings a bit, as was suggested by rsdata. (brake hoses are new too) The wheel spins great without the brakes on it.

I got all the new stuff from O'Reilly's. Should I try to return the calipers or rebuild them myself?
Or, is there something else that could cause the calipers to not release?...like the master cylinder or something.

 

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I am not a pro mechanic as many of the guys on this forum are, but I have been replacing brakes and brake pads, calipers and all the rest for 30 years or more. I have found that sometimes the "ears" on the brake pads are too big to allow them to slide freely within the caliper. I have at times had to use my bench grinder to grind a bit of metal from the pad backing material to shape them better to slide freely in the calipers.

When you have the front wheel off the ground, and spin the tire freely, have someone apply brake pedal and stop the wheel. Once foot off the brake, can you then spin the wheel freely again? Apparently not... but if the brake pad is not sliding freely back away from the rotor in the caliper, then it is not releasing from the rotor. Check how the pads might be binding within the caliper.

At this point how are you describing a pulsation? Is it a noise that you hear, or is the wheel brake rotor dragging against the pads?

As an aside, with all of that lube in the caliper, are you cleaning the brake rotor and pads thoroughly with brake cleaner spray, getting rid of greasy residue on those braking surfaces?

 

About the calipers; I thought when I released the brakes the caliper piston should withdraw a bit and any friction from the pads against the rotor would be minimal. Is that not correct? This is not happening in my case. After putting everything back together and pumping the brakes a few times, it's hard to spin the wheel again.

Also, it hasn't been more than 6 months (maybe less) since I replaced all the parts I mentioned.