aowRS

I recently noticed that the pads on my 231mm Tundra calipers were quite worn, so I picked up another set of 04465-35290 Toyota pads and installed them a few days ago.

The truck stops smooth & straight, just like it has since I installed the calipers in 2012 (I rebuilt the calipers before installing them). But when I come to a stop, I hear a groan/moan from the front brakes during the last couple of feet before the truck stops. If I come to a stop on a hill, and then take some pressure off the brake pedal to drift forward, it groans.

I always slip the tranny into 'N' at lights. Is there a chance the rotors merely have deposits from the last set of pads?

It's definitely an odd noise, and it's definitely pad/rotor related - not suspension bushings, joints, etc. All pistons retracted correctly when I installed the new pads.



Andreas

tocarunner

did you have the rotors resurfaced when you put the new pads on?

did you use brake cleaner after and before install?

did you grease the back of the pads before install?

could be dirt somewhere in the system that you are hearing. hard to tell over the internet, best thing to do is get back in there clean things up, ad grease where it should be, and see if it goes away.

ShouldaWornGloves

Tocarunner has a good list of "Should Do's"! One thing I'll add is: When replacing pads I don't always see the need for resurfacing the rotors. If I have no wobble (rotor runout) I'll hit the rotors with a sanding disc, in my air drill or die grinder, to score it and break up the glaze or sheen caused by the last set of pads.

Cactushead

What does shifting into N at lights do?

ThorInc

I would think he is taking pressure off the brakes?

J2F42C

I went and read your post on the rebuilding of the calipers. Nice job, but I have always been told to use only brake fluid on both seals when assembling and nothing else. No grease. You may want to remove the calipers and take a close inspection of the seals to see if the inner one is blinding perhaps as well as inspect the hardware, especially the pins.

aowRS

I will pull the calipers tomorrow and give the new pads a light sanding, as well as scuff the rotors. The noise is less though...

That's what I intend to do.

It makes $2 bills fly out of my ears.

When I installed the new pads, all pistons retracted smoothly.



Andreas

aowRS

Update: a few days ago I removed the front calipers & rotors. I cleaned the rotors (2-year old Toyota units) and used a grinder with a flex pad to evenly dress all surfaces. Then I thoroughly cleaned the calipers and made sure all pistons retracted correctly.
Lastly, I cleaned all of the shim pieces, chamfered the edges of the pads, and block sanded the almost-new pads.
Then I reinstalled everything and bled the brakes.

Verdict: the brakes seem to bite much better, but the 'groan' during the last few feet of stopping is totally unchanged.

If I've come to a stop and then gently nudge the truck forward in "D" while keeping medium pressure on the brakes, I'll hear the groan.

To recap, I purchased & rebuilt a nice set of 13WL (231mm) calipers two years ago. These were paired with new Toyota 43512-0C011 rotors, a Toyota 04945-35120 shim kit, and Toyota 04465-35290 pads. The brakes were utterly silent & smooth for two years. The only reason I installed new pads a few weeks ago is because the others were quite worn.

So, are there two pad compounds available for the 231mm brakes, semi-metallic & ceramic? When searching around, I seem to find inconsistent results.

When I block sanded these pads, and then cleaned them with brake cleaner, I could see bits of copper thoroughout the pad material. Also, sanding the pads produced a very dark, almost black, dust.

I wonder if the first set of 231mm Toyota pads were ceramic, and these are semi-metallic?

Thoughts?


Andreas

aowRS

Another update: since the groan noise when coming to a stop was still present, I decided to tear into things one more time today...

- took the rotors to a shop and had them turned
- gently sanded the pads again on a flat surface
- completely loosened hand brake and then adjusted drums (left was way out of adjustment).
- removed slack (and no more) from hand brake and buttoned everything back up.

After a few normal but firm 60-0 stops later today I can say that the truck brakes very, very well. I'll see if the groan remains during the next few days. At this point I've exhausted all possibilities. I can live with the quirk with how well the dumb thing stops.






Andreas

J2F42C

Is it more pronounced on one side or the other or evenly distributed?

I wonder if it isn't something else where the sound is being detected only when braking?

Did you put the rotors on the same side after having them resurfaced?

Just thinking out loud here...............

aowRS

The sound only appears during the last few feet of braking, is definitely in the front and is only noticeable if I keep my foot on the brake until a complete stop. If I feather the pedal during the last few feet I do not hear the groan.

Yes, I marked the rotors so they went back on the same side.

I'm not going to worry about it any more. It is significantly less since turning the rotors, sanding the pads, and correctly adjusting the drums & handbrake. It stops very nicely and arrow straight.

If anything changes, I'll update this thread.



Andreas

Kiroshu

I've seen a lot of vehicles with intermidately binding calipers produce this symptom you describe.

Debris on pads which seems to have been covered.. debris and or poor rotor surface.. also seems to have been covered.. I suspect based on the information provided it to be poor quality brake pad material.

Hmm.. interesting.

So this problem is directly related to happening right after replacing the front pads..?

Do we have any other noises or symptoms from the vehicle..?

Front wheel bearings..? Loose..? Noise..?

Do you have access to a vehicle lift..? Possible to try and duplicate the problem while driving on a lift and observing..?