New wide five brakes groaning after a stop

Next time you pull the pads (for any reason), chamfer the forward (leading) edge at about a 45º with a file.  It doesn't have to be super-straight, just chamfered.

The disk pads are supposed to be just touching the rotors when the pedal is "off" so there will always be contact, but you may be seeing excessive pad pressure with no pedal, or the pad's piston is receding slowly, or the caliper is dragging.

Something to look at (with Carey's guidance, of course!)

If it were the rear I would say a faulty inline residual valve, "groan" possible wheel bearing? ( Just trying to cover it all) 

Did the chamfering already.  Slides were lubed well.  I don't think it's wheel bearings because I've heard that sound before.  Noise is only after rolling forward after braking (kind of embarrassing in parking lots).  I think it's the caliper.  Carey and I have been in contact & I also posted on the Samba for clues.  My gut tells me it's the caliper not retracting after heating up.

first guess is the caliper is not retracting. second thought is that they are empi disc brakes and it could be anything. Are these with the floating pins or do they slide on the step? if the caliper is ok then you may  have too much line pressure after releasing the brake pedal. your comment regarding the pads being glazed is for sure a sign of the pads dragging. excuse me for the empi comment but I am not a fan of their products.

Had serious groaning from my Empi rear brakes when new. The chamfering didn't work for me, either.

What did work (mostly) was a change to ceramic pads. As it happens, my rears take the same pads that were used on Ford Taurus brakes for many years, so there are a number of after market choices available. I don't know if that's the case for yours, but a different pad material was the answer for me.

They used to be quiet until they warmed up, then groaned really loud when the brakes were applied very lightly at low speeds (2-3 mph). With the new pads, they make the noise slightly when first applied from cold, but the noise goes away completely when they warm up after the first few applications.

The pads I ended up with are ceramics made by Bendix.

@Tom Blankinship et all this is not isolated to EMPI, my Wilwood brakes started "moaning" out of the gate last summer  @Sacto Mitch I will pass along the ceramic pad idea to Carey.  

I had a moaning issue on my old IM when I was backing up only and we traced it to the bracket vibrating.  I wonder if at times the quality of the bracket used might be an issue.  Just saying. 

...I remember when hearing moaning was a good thing...

Going to throw belt and suspenders at it.  Carey is shipping me a new caliper and going to find the number for Bosch QuietCast pads (this is a major challenge, BTW).  The Bosch pads are a metallic/ceramic mix.  @Joe Fortino, I'm not comfortable using pure ceramic on the street.  Read up on them.

Tom,

Had this happen many times with the Rear Disc brakes, Its a caliper spacing issue. You need to space the caliper away from the bracket so the inside pad has more room to retract. A very thin washer installed between the caliper and caliper bracket will do the trick.

Greg

Sounds like something you could do quickly and cheaply before you go to the trouble of swapping/bleeding a new caliper and all....

Good luck, Tom!

VSpyder posted:

Tom,

Had this happen many times with the Rear Disc brakes, Its a caliper spacing issue. You need to space the caliper away from the bracket so the inside pad has more room to retract. A very thin washer installed between the caliper and caliper bracket will do the trick.

 

 

Greg

I had a similar issue a year ago when I upgraded to rear disc brakes. The brakes would make a noise (like the groaning you mention) when coming to a stop. Not every time, but frequently enough to be annoying.

I did the washer spacer trick as Greg mentioned. Noise went away. 

MusbJim posted:

VSpyder posted:

Tom,

Had this happen many times with the Rear Disc brakes, Its a caliper spacing issue. You need to space the caliper away from the bracket so the inside pad has more room to retract. A very thin washer installed between the caliper and caliper bracket will do the trick.

 

 

Greg

I had a similar issue a year ago when I upgraded to rear disc brakes. The brakes would make a noise (like the groaning you mention) when coming to a stop. Not every time, but frequently enough to be annoying.

I did the washer spacer trick as Greg mentioned. Noise went away. 

Thanks guys,  @chines1 hopefully this does the trick. 

VSpyder posted:

Tom,

Had this happen many times with the Rear Disc brakes, Its a caliper spacing issue. You need to space the caliper away from the bracket so the inside pad has more room to retract. A very thin washer installed between the caliper and caliper bracket will do the trick.

 

 

Greg

Thanks Greg!  This makes sense and sounds very promising!

Yes we have to shim almost all of the calipers, and t his is done with caliper shims, which are just a washer in a variety of thicknesses. It is possible you need a thicker/thinner one...

@Joe Fortino  your issue was (I believe) the Airkewld hat not being true.  I just cut up an axle to make a fixture and I have your hat on the lathe.  It isn't off my much, only a few thou, but enough that you can feel it in the pedal and hear it "lump".  I know for sure shortly...

So, is Joe fixed yet? Is Tom going to have groan-free braking?

Inquiring minds and all.....

Joe's seems fixed but its been raining here for days.  The hubs had 0.020" runout on them so we machined them and they are now smooth.  A long drive will tell for sure.  Tom's IDK yet...

chines1 posted:

Joe's seems fixed but its been raining here for days.  The hubs had 0.020" runout on them so we machined them and they are now smooth.  A long drive will tell for sure.  Tom's IDK yet...

Thanks @chines1, looking forward to picking up next week. You all are the best. 

Just drove home from Special Edition (2.5 hours) then spent the next 90 minutes driving the kids around and not one groan from the brakes! @chines1 you are the man. Thanks to everyone for at the shop, beers on me next week.